Love how you gave the quick answer, and then gave the support… this respects the watcher and allows us to determine what we want or need to watch. Greasy job. And great job on the supporting video.
I retrofitted my 90 year old home with closed cell foam under the roof sheathing. There was effectively no air sealing or insulation there before. My natural gas usage dropped 50% in December in Ottawa. This video is making me even more confident.
I love your videos man, especially this one. Straight to the point to those with a low attention span and want a direct "yes or no" but then a full technical explanation. Keep up the awesome job!
Yup, we had a large portion of our hallway ceiling collapse because the cellulose took on so much water, then the plaster soaked up so much water. It ever so slightly dropped over the years of the leak and one day just collapsed. The weight of the plaster was incredible.
Leaks are tricky even at best if circumstances. Our house had a roof leak for years but we didn’t known because the cellulose absorbed it until it become a huge leak. Fiberglass loose fill 7:21 will let water through quickly. I’ve been using 12/12 and 10/12 pitches for years. We use closed cell foam on our new builds AND we use Huber Wood Zip roofing and Ice guard 4’ up and high quality underlayment. The chances of roof sheathing damage is very very low. Now, could damage occur one day if the future home owner don’t take time to visually inspect their shingles? Yep. But then concrete and steel eventually erode from neglect also. I’d the price of closed cell foam was 1/2 it’s current price, I would ALWAYS use it to make our attic spaces un-vented and all our walls and rim joists sprayed over with 3” of Closed cell and then the balance dense pack fiberglass we use 2x12 rafters and floor joists. Here is some facts. Energy prices are going to quadruple as the “greenie religion” forces everyone to use electricity only. Better to pay for insulation and air sealing today. Payback isn’t going to be all that many years.
@bret9741 Solar with batteries is now the cheapest way to produce electricity. Here is a great video comparing coal, gas, wind, and solar. m.ua-cam.com/video/6_BGHy4sfMs/v-deo.html
We have open cell sprayed on the underside of the roof deck, It was done in 1998. The roofer did a poor job and many nails missed. These small leaks were not big enough to drip below, but big enough we noticed soft spots in the decking. Rather than take the roof off and deal with the soft decking we instead nailed 1x4" perlins through the shingles and put on a metal roof. There is now a one inch air gap between the original roof and the metal. Not only did this solve the leaks but the house is noticeably cooler in the summer. We are in Indiana so summers are very hot.
Good testimony that shows it is NOT the end of the world for a few leaks. People make out like the roof leaking inside the house will limit the damage.
I have seen 5 layers of shingles on one roof. After 50years Renovations. You see a lot. Old timers theory was if it leaks and you covered it up to solve the problem. You are only fooling yourself. The moisture is still in there. Stupid thing like capillary draw and physics-based tell you that if the problem is eliminated then it is solved. My former 20 year apprentices ousted to have a saying from his grandfather. "No one can afford to do it right the first time. But they can always afford to do it right the second time. ( after they ripped off what they did the first time after it failed)
Hello Mike and thanks for your very informative videos which were just recommended to me. We have a 30 year old home on Lake Michigan. It has a formed on site standing seam copper roof. The underlayment is Grace Ice & Water Shield (directly under the copper and sticking to the sheathing decking (7/8th plywood). This building has cathedral cedar ceilings and a non vented roof using blown in cellulose. Lightning rods on the ridge cap recently started leaking (broken calk seal) and some of the lightning rods had penetrated the Grace Ice and Water Shield under the ridge cap. This caused black mold on. the interior ridge beam. The fire retardant in the cellulose limited the mold - but the ceiling cellulose near the ridge was wet from condensation. The temperture at the copper was measured at 140F wile interior a few inches away was at 80F. We are removing all of the ceiling cellulose and replacing it with closed cell foam. The insulation contractor wants to install 6" of closed cell foam (icynene) directly to the underside of the roof sheathing. This would create decking encapsulated by Grace on one side and closed cell foam on the other. There should be no moisture in the plywood but also no way for any trapped moisture to get out. In one of your replies you indicated that this situation should be dealt with using "sheathing membranes". I did some research on sheathing membranes and it looks like they are just an impermeable vapor barrier? deltaacademy.dorken.com/resources/the-fundamentals-of-sheathing-membranes-and-air-barrier-protection/ Can I have my contractor spay closed cell foam directly to the bottom of the sheathing? Or we need to stick a sheathing membrane on first then the foam over the top? I really don't want to cut holes in the house to vent the roof because we live right on Lake Michigan and often experience high winds and driving rain and snow (and 18 foot waves) Lots of information, some want me to create a vented roof by cutting holes in the house and venting the ridge cap because they say the sheathing must be vented to dry and cool. I'm a licensed engineer (not a building engineer) and find conflicting advice. Thanks for your help.
I really appreciate your approach to these videos. Concise, thoughtful and informative! After running a renovations business for a little more than 20 years now, I find myself building small-ish cabins for use as long term rentals as well as to sell. Looking to keep my costs low, I have looked to an idea that I used about 12 years ago on my own house build with a semi-vaulted roof system. (Scissor trusses) To obtain the required R value in the heels of the trusses, I was forced to use spray foam. After weighing the costs, I ended up using two layers of 4 inch blue Polystyrene foam insulation attached with quick -forming adhesive and recessed about an inch from the sides of the trusses cavities. Then, I filled those gaps with spray foam and added (approximately) 2 more inches of spray foam over top of everything. The Polystyrene boards were acquired from another job (re-doing a metal flat tar roof on a Home Depot building) so it saved me some serious $$. I too thought that insulating the roof deck would be advantageous over insulating the ceiling, and it has been maintenance free ever since. I was concerned that the minimal contact of the Polystyrene to the roof deck would be an issue, but it has been fine. Roof is a 4/12 with tar paper underlayment and 3 tab asphalt shingles in Edmonton Alberta. Any thoughts on this? Love your channel - liked and sub'd!😊
The principals are all the same, except you have a tough job trying to repeat what we are. Self-adhering rigid insulation, and conforming to the irregularities of the space created. Much depends on your diligence to get it well adhered and sealed. Air sealed is the major.
@@SprayJones agreed. I'm always looking to save $$ where I can, but the long term savings of a solidly insulated (open vaulted) roof system far outweigh the higher initial costs. I will do more research for current standards in my BC here, but I remember having to convince the building inspector that the spray foam on the roof deck option was a good and proper way of achieving required insulative values in the roof structure.
I have watched 20 videos and asked about 10 questions. I am finishing my 2nd floor cape in MA with a 12/12 roof with closed cell insulation ONLY. Rest of the house is open cell. I feel 100percent confident that its the right thing to do. I dont know what it will cost but it doesnt matter. I am looking forward to a great envelope protecting me from summer heat and winter cold.
Great video - thanks! Good to have solid info like this....Ive had many discussions/arguments over exactly this! I Had Closed cell sprayed in my attic roof deck and walls - in a 100 yr old wood stick frame house. It tightened everything up and Ive never had a problem since. It has paid for itself on my heat bills over 4 years.
I think you made a good case @7:30 for not using closed cell foam. Once you encase the roof deck in closed cell you would have no way of knowing if your roof is rotting away until your shingles start to fly off. Sounds like cutting the roof deck with a skilsaw might have been avoided if the leak was detected early. I like the idea of open cell for that application, closed cell everywhere else.
Just ask a roofer how many times do they have to replace roof sheathing on a conventional roof when they replace shingles? How did the guy in the story I told discover the issue?
The key is if the roofing allows trapped moisture to get out. I would assume most asphalt shingle assemblies will but not nessarily. If you do have a leak in your roof with spray foam on the underside you will not know it until the sheething, structure has rotted away. As stated, that foam glues everything together, it will be very difficult to replace that. Given that roofing guys often have to replace sheets when re-roofing houses, I would be very nervous putting spray foam on the underside of that decking. Saying that, there certainly are lot of advantages in spraying the underside.
I guess you can add that closed cell is IRC code required in the United States for any unvented attic where the spray foam is applied to the underside of the roof deck.
Unfortunately where I live in the south termites are absolutely out of control and you don't find the damage until it's far too late. I have open cell foam and all of my house, but dearly regretted given the circumstances
Just found your channel. Good info. Somethings to mention. Closed cell in this scenario needs to be air tight with no air leaks through to roof sheeting. In my experience, air leaks in cold climates can drive enough moisture to cause structural damage from rot. Also ice dams can be an issue. We've had good luck with using baffles to create 2"+ ventilation space and thus maintain a cold roof while still gaining the advantages of closed cell foam, the added rigidity, the conditioned attic space, much less ice damming and, for me, accessible ceiling systems. The baffle idea seems like common sense to me and to the installer I've used on multiple jobs but I've never seen it mentioned in any foam industry info. Wonder why?
@@SprayJones his point seemed logical I wonder why you did not agree. Could you please explain, thanks so much. Also if you have an air gap there if you had to replace any sheathing, it would not interfere with the spray foam.
@@davidhannan2023 The air gap is a fine way to hybridize ventilation while remaining sealed. Engineering tests have been done on this. Google Search: BA-1409: Field Testing Unvented Roofs with Asphalt Shingles in Cold and Hot-Humid Climates The hybrid method with the air gap between the foam and the roof is what I am going to do on my new roof since I have to replace ALL of it, and I'd rather keep my roof cold in the winter, so it doesn't get assistance melting from inside.
We have to have some type of ventilation in attic spaces by code in Michigan. Mechanical or passive ventilation your choice. With proper ventilation your shingles will last longer and not blister up. I have seen house's roof sheeting rot from spray foam and no roof ventilation. Currently ripping out finished spray foam basement. They sealed the masonry. Masonry loves to wick moisture. Condensation built up in blocks over time. Till it leaked in basement. The masonry needed an area above grade to dry moisture out. With roofs the issue is condensation. I tell people to make sure they have roof vent baffles installed before spraying foam.
Watch the video I made on shingle life and SPF. Then the 4 part series on non-vented roofs. Code is based on open cell fibrous NOT SPF. So you cannot import misaligned rules to this system.
Half way through my remodel i decided to swtich to nonvented attic with spray foam. I have a metal roof no penetrations. The plumbing vent goes out the siding near the peak then up above the roof line per code. If i did it again i would have used zip tape over the rafters to protect from nail holes. I also would have used zip roof deck. Im not a pro builder but i do think things through. Fortunately i used a metal standing seam roof instead of shingles so my decking ahould stay dry.
They are assuming a 'drying season'. And they are assuming everywhere has that when they say it can be used everywhere as long as the pitch is greater than 3/12. That is just not so. In my particular area which is a temperate coastal rain forest things that wet just don't dry out with our average of thirty days or less of actual sunshine (combined with winds over 100 mph and 170 inches of rain). I am sure there are other such climatic zones in North America. Engineers and architects have a long history of failures so I just wouldn't be comfortable with any blanket statement from them and skeptical of particular local advice. I can show you one failure after another in our small community alone that was caused by bad design from 'certified' engineers and architects. When you combine modern building materials and water you have a large problem. Imagine six months of wet on OSB!! Then add it some freeze thaw cycles.... Spray foam is a good thing in limited situations but allowing a structure to 'breathe' in all but desert conditions is very important. The other new drawback I hear of and see is over the long haul the foam both open and closed 'shrinks' away from the dimensional lumber causing condensation where those openings lead to a cold external surface. I will be much more comfortable when I have seen forty years of existence of any brand of foam used successfully in tough climates. Always and interesting topic.
@@SprayJones That is an ignorant reply. A car is not designed with the lifespan or price of a home and in any case proves my point for all the absolute failures the auto industry has foisted off on the consumer. Is that your goal? Get your pile and get out before the failures come to fruition. You use a very poor analogy in any case as it disproves your position. Most car successes were built on a solid years long history of performance while their failures came with no eye on what preceded much as the spray foam in a home phenomenon!
Douglas, I whole heartedly agree with you. I have the same concerns with this application trapping moisture between the foam and roofing. I think it's okay for walls but not roofs. This will also bake asphalt based shingles due to the absence of cooling of solar radiant heat gain, which I have personally seen with SIP panel and rigid foam structures. There is also sick house syndrome from structures being too air tight. Remember, for every action there is an equal and opposite reaction that sometimes is exponentially greater than what you are trying to solve. Not everything "new and improved" is better. I made the contractor remodeling a portion of our camp (I was not the member in charge of the project) put venting baffles in before the foam. I do roof and building envelope inspections an have been concerned about this since it started to be promoted, by you guessed it, the sprayfoam industry.
Using closed cell foam in an unvented conditioned space has a big caveat and could be bad if the roof isn't done correctly. If you have a conditioned attic space then the roof is no different than an exterior wall assembly. If you use closed cell foam on the inside it acts as a non-permeable vapor barrier on the inside. This means that the outside of the wall or roof needs to breathe all the way through your layers of your assembly to the closed cell foam below. This means no peel and stick water and ice shields on top of the roof sheathing. If you do that then you have your wood roof sheathing sandwiched between two water and vapor impermeable materials. Bad idea since no system ever keeps 100% of moisture out. Very tiny amounts of moisture will get into any system but it will do no damage if it has a very easy exit. That is why any system should only have one vapor barrier on one side. Closed cell works well for walls because you have a rain screen material like siding that keeps most of the moisture off your outer wall surface with a small gap or drainage plane behind. Then your house wrap is water resistant but vapor permeable. This vapor permeable wrap allows any small amount of moisture that does get into the wall system to get back out once it is stopped by your impermeable closed cell foam. So closed cell foam for your attic is fine as long as you use a similar exterior system for your roof. Just use a vapor permeable but water resistant underlayment for your roof system.
My builder said he only sprays open cell because of yrs of experience with both. He's had way more issues, both short and long term, with closed cell. I do know I have leaks and have no clue where the source is. My house stays a consistent temp yr round and my electric/gas bill stays relatively cheap compared to my old house and other people I talk to. My attic is unvented conditioned with 4" of open cell foam.
I'm wondering if there could be a condensation issue in colder climates, if any research has been done how this practice holds up to the test of time? A life long carpenter and builder I think having air flow between sheathing and insulation will alleviate the chances of condensation condensation.
How does the roof dry to the exterior? Most roof papers are not breathable air barriers the same as say a tyvec. If the roof deck is not breathable there is where the problem comes into play. I have been in the insurance industry for over a decade and seen numerous roof systems rotted because of spray foam on the underside of roof decking. And most shingle companies will not warrant the shingles anyway. That is probably why the engineer put that disclaimer in ther
This is not a google reply I have been in construction trade for 30 plus years and the insurance industry the last 11, my response is from seeing it not google. That’s why the engineer leaves himself and out by saying it needs to breathe
@@patholland8835 you are correct . There have been several instances of soft decking and shingles coming off on houses under 10 years old. Hopefully these spray foam installers are held responsible when this all goes south . Closed cell is ridiculous against roof decking, period imo. A lot of this stuff works on paper when the engineer is writing it
Exactly. Maybe you can get away with it for a while. And closed cell certainly can prevent moisture and/or condensation issues from the inside. And sure, the closed cell might prevent the leaks from entering the living space, but it's also going to cover up a ton of smaller problems over time. Someone explain this - why is it best practice to use a rain screen siding setup with ventilation, but (apparently) fine not to do it on the roof? The walls are vertical, often have soffit protection, and far less water pressure, plus wall peel and sticks/tyveks/etc generally are FAR more vapor open - but time and time again you find unvented setups that have rotted from water entering at failed penetrations and then not being able to dry fast enough. You are creating a sandwich of two non-permeable materials with a water sensitive material between on the most exposed part of the house which also happens to have thousands of penetrations from not only fasteners, but also vents/skylights/valleys/etc. Ice and water shield isn't vapor permeable. It's going to hold that water a LONG time no matter what the temp or the sun thinks about it. Closed cell isn't vapor permeable. The only way out is going to be the failed penetrations, open seams, or wicking through the rafters or roof sheathing itself. I've seen this pushed a bunch of times, but never have I seen anyone explain that.
I feel sorry for roofers and homeowners with spray. Most roof decking needs to replaced at some point, a lot of bad roofers out there. How hard is it going to be to rip that ply off there to replace? It’s going to be super expensive and difficult. Then you’ll have to reinsulate. Traditional insulation in areas that need access for service is a better option long term. Plus, I’ve seen a few bad spray jobs that owners were getting sick
We recently completed a 12/12 pitched roof with the axis east and west for future solar. Direct southern exposure and the plans specified closed cell foam on the underside - no ventilation. I've been doing this for almost 50 years and the thought of a cathedral roof with no 1" continuous ventilation from soffitt to ridge vent used to be heresy, but now is the preferred method. I have been in many an attic that is suffocating in the summer heat, and the old 3 tab roofs would literally curl up at the edges like bacon and then a stiff wind would bend them up and over at the next edge. My concern is what roofing can stand up to the south sun with an insulting layer under that allows no heat dissipation? You mentioned 'ice and water' as the underlayment and the specs did note the roofing material needed to be approved for this application. I'm in Seattle, so not so cold and not so hot, but plenty of water. In addition, our building inspector mentioned the dew point as the main factor in negating the need for ventilation. I have a roof interior coming up for insulating and want to be convinced that this has stood the test of time and I'm just ignorant. In the 80's we went thru a period of maximum building wrap, sealed windows, caulking everywhere and vapor barrier on the inside, but the exterior envelopes leaked, the insulated walls could not breathe and there were whole blocks of apt buildings requiring residing in less than 10 years. It was a major problem up and down the west coast from Canada to California. I subscribed and am working my way thru your videos...Thanks for all the info. I know this is part of your marketing but I also know when someone loves their job.
Richard go to the playlist on this channel dedicated the vaulted ceilings. Watch the 4 part series on non vented roofs and the shingle life video I did. That should quell any normal concerns.
I put closed cell up 20 years ago on vaulted roof around 1.5 inches never had any condensation i can say for sure because much of it is unfinished to this day I'm in Chicago area. Before i put up any foam I waited for some heavy rains to make sure no leaks. If I were to do it over again I would use ice and water dam from bottom to top. I did have a woodpecker make a hole in the wall one sheet of OSB damaged about 2 feet by 4 feet spot to fix and I scraped the OSB off the closed cell foam without damage to foam. This foam won't hurt any shingles.
@@portagepete1 thanks for the vote in favor, my wife wonders what takes me so long to decide...but I just watched a pros and cons (mostly cons), and the #1 issue was flame retardants (mandatory). Any bad smells allergic reactions,..cancer ?
I know this video is two years ago but I am just getting into the spray foam world. Had lots of people talk about needing to install some sort of roof baffles or some sort of ventilation. From watching this video it appears that that is not the case, correct. Spraying UPC 2.0 foam, living in Palmer Alaska. Thanks!
You do not. Commercial roofing does not use an air space between a deck pan, rigid and a top membrane. It's time to break out of 75 year old technology and the dogmas that go along with it.
I had multiple spray foam installers (got three quotes) tell me it was fine. My roofers wanted vents, I told them I was spraying to the roof deck - they checked with the shingle manufacturer to ensure they would be able to offer a warranty before they even started on the roof (wasn't a problem). I then checked with my Hydro rep (when I was having my house assessed for energy efficiency grants) and he stated that a vented roof would actually lead to more problems and the only reason that it's still sometimes done is because building code is lagging behind the technology. Same reason the spray foam guys actually told me there was no point in spraying more than 4" of foam on a roof or 3" in a wall but code may still require it because it's based on fibre glass batt R value (or did when I had my house sprayed and inspected). As a result they had to spray 4" on my basement walls to pass inspection even though they said there was negligible returns going from 3" to 4" on a wall. My only concern was the point brought up earlier, that if there was damage to the roof you would never know about it because the water would take a long time to go around the foam to get into the house and show itself. That's where investing in a proper roof comes in - get the membrane, get the ice and water, get a company that does it right.
Recently had open cell sprayed in my attic. Noticed a leak during a rain storm shortly after due to the expanding foam pushed off our ridge vent. I had all 3 ridge vents removed and shingled over the opening. Problem solved but it cost the spray foam company $675 for this work. Ridge vents should be removed prior to spraying.
Can you use close cell on 1/12 pitch metal PBR roofs.( in south east US) Have perused your vids but can't find anything spacific. Thanks for your ethics's just wish ALL spray foam contractors had your integrity and desire to educate others. As for as I'm concerned that is what transparency is meant for.
Great vid, very helpful. I'm embarking on a closed cell job for my roof deck. Two quesitons if I may! 1.) Is adding stregth to roofdecks for snowload a universal benefit when applying at least 4" of closed cell? 2.) We just completed some sistered rafters to the attic roofdeck. New lumber to old rafters. Should the new lumber be dried to a minimum moisture before spraying foam?
I believe one important Building Code detail... as Part 9 of the NBC is being cited... you don’t mention is the requirement for a vented air space between the top of the insulation and the underside of the roof sheathing. I’m not saying SPF cannot be installed in this location. However, since no vented air space is being provided and most jurisdictions (Cities) must follow the prescriptive Acceptable Solutions listed in their Provincial Building Code, the use of an Alternative Solution may be required. I highly suggest the local Building Inspector is consulted before SPF is installed to determine if an Alternative Solution will be required.
You are correct. For the last 12 years this has bee placed to bed. The Province reviewed this and has approved it. You have to apply with your SPF paper work at the time of permit and then it will be granted. There aren't too may places that have an issue with this.
Your videos have helped convince me that an unvented condition attic is the way to go. We are going to put new asphalt shingles on just prior to spraying closed cell foam on the rafters. What kind of underpayment should we use?
I live in the south and have an older house. I have a ridge vent and side draft exits, do those stay? Can i also leave the blown in insulation that's already there on the floor? Would you recommend closed cell?
I live in AZ and also wonder if I used closed cell do I need to remove existing blown in insulation and block off my attic vents. Also do you need to have the attic ventilated with your hvac also
It would be the same. Vulcanized roofing over the top. The other safety factor is to install roof wrap. On the roof. Usually a water repellent membrane. Before the shingles are applied.
What about open cell for the underside of an EPDM flat roof? I assume this means the roof assembly needs to dry to the inside during all seasons which requires proper HVAC maintaining low RH in the dwelling.
We treat EPDM flat roofs on a case by case basis to review all variables and liabilities. In short we have sprayed all that we have done with closed cell because it was the right fit for the inside.
Let me be clear: YOU ARE CORRECT. What is amazing is that here in florida they STILL buy into the myth. At least the folks I have had over to my home for spray foam quotes.
Keep in mind that roofs with a 3:12 pitch require two layers of asphalt paper under the shingles. I would be very careful about using closed-cell on less than a 4:12 pitch. What you fail to understand is that the closed-cell foam provides a moisture barrier under the plywood (like a vapor barrier). So any water that makes it to the plywood will be trapped between the ashpalt underlayment (which is a vapor barrier) and the closed foam insulation. This will impede the plywood from drying out. So your assumptions that all water will just drain off are incorrect. All water has to do is get under that asphalt paper and soak the plywood. This can happen if the roof is not sheathed and flashed correctly. The advantage of a vented attic is that if water does get to the plywood, the plywood can dry out from underneath air in the attic. That is a key difference. Putting in closed cell insulation in the roof can be done safely and it is a great insulation system, but if human error comes into play, it can rot large sections of the roof before it is discovered and that is why it is not widely used. Presumably, if water got under the 15 lb asphalt paper and soaked the plywood, if open cell foam insulation was used, then the plywood would have a way to dry out. What we are talking about here is what happens when their is a roof failure. The closed-foam system can greatly increase the scope of damage caused by a roof failure. Also remember if the roof is a tile roof, then the cost of repair can be significant.
Question. Is there an advantage to 1" of closed cell followed with 3" of open cell? As opposed to only 2" of closed cell? Some installers are recommending this application mainly due to cost of material. THANKS!
You mentioned a resource indicating it was safe to use CCF under roof decks on 4/12 or greater shingled roof….. What about low slopes roofs. Say a 2/12 roof using 45 mil TPO membrane ? Typically residential manufactured homes with TPO roof membranes are not glued down. CCF would be great for strength on an older structure, but what about future roof leaks? I should say this is in Florida. My home was narrowly missed by hurricane Ian.
Local SPF installers need to have their engineering done with state valid firms. You have to source that locally. But it is NOT as hard to find as you may think.
You can't use asphalt shingles. They seal eachother in with tar strips. They are referring to cedar breather and cedar shake roof shingles that allow moisture to condense and evaporate from under the shingle back into the outside air. Otherwise you need a vent beneath the shingles making the sheathing the shingles are attached to the same temperature as the air outside
No you do not. Please get off here if you are spouting uneducated nonsense. We have been doing this for 17 years, and we are nowhere near first in the industry.
This poster is correct. Asphalt roofing systems create a vapor barrier. www.owenscorning.com/NetworkShare/Roofing/10013915-Deck-Defense-Technical-White-Paper-October-2011.pdf Joseph Lstiburek is one of the authors so don't let the Owens Corning web site lead to a different conclusion.
Can you use 2" of closed cell then fill gap with open cell? I have an I.C.F home basement, and 2nd floor 3rd floor is a mix of 2"x12" walls and 2"x6 walls ,I'm going to have a condition attic that is cathedral type , the contractor I'm looking to use is recommending open cell with the thought that a void in the 2"x12" wall area and possibly the 2"x6" wall will create a bad echo ??
Does this hold true for metals roofs as well? I have an 8/12 pitch on a new build and have ice and water the entire roof prior to metal going on. No strapping between roof deck and metal. thanks. In Quebec (cottage).
I'm an engineer and I agree that this is ok but using an explanation of "because an engineer says so" is just circumstantial inference and not a technical defense. I would have liked to see the technical explanation included. I know there are minimum thickness requirements based on location to prevent dew point condensation and different things like that.
I don't go into overly technical explanations. No one wants to watch that and the time to make the video does not pay off with views or ads run. So I keep it simple.
So if closed cell was applied, I’m guessing you wouldn’t use any iceshield beneath the shingles? I can see the inspector challenging this lol. At the same time, although I completely agree with your argument, one would never really know when there’s a breach in the osb sheeting, beneath the shingles.
@@SprayJones I wonder, though, could you have a problem with water seeping through the plywood to the bottom and have no where to go and get trapped top and bottom, or should you use an ice shield but leave some less water tight area at the very bottom in the eaves?
Wow, I love your video. Only problem is that I saw it too late. We just had our roof replaced with aluminum shingles. The underside of our roof sheeting is insulated using closed cell spray foam. The Installer claimed that he could not put the Aluminum Shingles directly on our existing plywood. He took off our old shingles and weather barrier and add a false roof over our 12/12 sloped roof. And in doing so he neglected to raise the flashing around our cultured stone chimney. As a consequence, to his actions, we now have water entering our home where the closed ends at the lower edge of our roof. My question is could aluminum shingles (which vent extremely well) be placed over a roof that has been spray foamed?
Well in my local building code change this to you can't use closed cell on roof underside and encapsulating the rafters. The reason being there was one or two roof collapses because of a poorly maintained roof and the leak over decades had rotted the sheathing and rafters and there was no signs of a leak inside, so no one checked. You can however use open cell because once the foam gets saturated then it would be visible inside that you had a leak and would then go up and inspect the damage and make repairs, plus it was a good idea to replace or dry out the damaged foam. Also our snow load where I live is 62 lbs per square foot which is also a factor. You say these engineers certify that product under those applications, well sure they would, but a poorly maintain roof would not have a bearing on that certification, that's on the owner to ensure their investment is protected. So I guess one or two dummies wrecked it for the rest of us.
I have one stupid last questions. I promise this will be my last. I am following as I understand it your advice. 2" closed cell on my foundation slab, 2-2.5" in my wall assembly (I will have Zip R-6 a sheathing), 3" closed cell on roof deck in my conditioned attic. So here is my stupid question. Should I also go 2" of closed cell between my ceiling and my conditioned attic? I am sure the answer is yes, but trying to cut some cost and just don't know. If my attic roof deck is closed and my walls are closed, is it worth doing in the ceiling of my ranch home? Thanks, sorry for asking so many questions, but I trust your opinion.
If you have sprayed to the roof deck you do not need insulation on the drywall ceiling. It is hanging in mid space... For the record my suggestions are subject to code approvals for your area....
@@SprayJones Thanks. I just got a quote back from a contractor. I am pretty shocked. In short here is the details of the quote. Heated and Cooled square ft. 4,300 12 ft interior ceilings. I asked for the following. 2" closed cell foam for the slab. 2-2.5" on all interior wall within the heated and cooled space. 3" closed cell foam on the roof deck within the conditioned attic space. 4" open cell ceiling that is the garage ceiling to the conditioned attic. Total Bill 73,000.00 for the job. I am shocked to say the least.
Awesome Videos you’re doing your community a great service thank you! Question- when you talk about the case with the man with the 12/12 pitch going to the 4/12 and water getting underneath the shingles… why would they have had to apply more spray foam when doing the repair? Wouldn’t the old closed cell foam remain undamaged and flat against roof deck so that the new piece could simply been placed flush right over it?
You are an awesome tuber, THANK you for getting to the point strait off, for those who just want tje answer you did us a huge service. Ill subscribe for that
I noticed that you sprayed the complete 2x4 even on the bottom for the ceiling. Does this need to be done in order to make it all vapor proof? I am having my addition spray foamed with the following. Rafters are 2x12" 12" on center. 3" closed up to the roof deck then an additional 4.5" of open cell. So this leaves the bottom of the 2x12 not sealed. Should a plastic vapor barrier be installed. Have not talked to the contractor about this yet. Project site is in central Massachusetts
I seen metal buildings with flat roofs which spray in foam insulation if I built a metal building I would do this spray in Foam and insulation and I would cover it all up with metal It's a metal roof if you can't find a hole in a metal roof you do not belong on that roof please comment back if I am right or wrong thank you I used to do roofing for many years burn down rubber roofs Hot roofing jobs And also shingle jobs I used to find the holes in the hot roofs and the burn down rubber roughs before I found the shingle week a less it was a single missing or just a natural HOL E in The Roof or a less it was in the valleys or around distinct pipes or around the chimney every so many years you're supposed to go up there with a bucket of gunk and re do them thank you for this video
My neighbour just had open cell foam installed - I'm located west coast Scotland very wet, damp, humid conditions most of the year, wettest and windiest place in Europe... Closed cell sounds better to me... Can you tell me about off gassing with open and closed cell please, you seem to know your stuff, thank you in advance.
Jury is still out on this as it is too new. Engineers are wrong a lot as everything works on paper. Every hot roof I've encountered have moisture retention issues. This will cook shingles but not affect metal, tile, or slate. Will probably cook synthetic slate. Buildings need to breath or you get sick building syndrome.
1. This has been around for 30 years already 2. Engineering has shown this to be a proper method 3. Building codes support it 4. Shingles last just fine with SPF 5. Commercial BUR roofing does not vent, how is SPF different You comment ignorantly instead of learning.
@@SprayJones so you insult rather than listen to a different point of view, speaks a lot about your character. I've been roofing since 1980 and now troubleshoot and assess problem roofs. I see on a daily basis issues with unvented roofs. BUR is a completely different system that typically uses different insulation and is not as common today as single ply or mod-bit which usually use rigid foam and fiberboard. I have personally seen shingles turn to potato chip consistency from insulated sheathing. Go sell your product like a used car salesman.(insult intended right back at you). Shingle manufacturers require vented roof decks, read instructions and warrantee requirements.
What about a flat roof with modified bitumen torch down roofing? When they're talking about three and twelve they're specifically referring to using shingles, right...?
Hello Mr Jones: I have a couple of questions.. I'm having a new all metal building put up.. The beams, girts and trusses are galvanized, do l need to prime them with something prior to spry foam? #2 How thick should the foam be on the under side on the roof? Non vented roof.. Thank you.
I have a small leak from a solar rack and the closed cell has ultimately kept a ton of water out. I have been trying to get a contractor to simply fix the roof and it is a nightmare!
@@SprayJones yup got a pan under it. No one wants to come out and deal with thr panels. It isnt like it is a small job i want them to cover a couple of intrusions and replace done shingles. I might as well go up and do it.
@@K0gashuk0 Find a handy siding and exterior contractor. Make friends, they have all the skills of roofers. Plus all the safety gear for getting up. My dad fell from a ladder getting onto the roof that ended his life at 57.
Thank you for your videos! I enjoy learning from you! Would this also apply to a metal pole building? I want to have the walls and inside roof metal sprayed with closed cell foam, but I am concerned about ventilation. This building will eventually have heat, but no A/C. Do you have a video already on this situation that I may have missed? Thanks for your assistance!
This is an older video, so you may not get a response from the author. I am preparing to build a house and have done much research into spray foam. If you use closed cell spray foam, make sure to get enough thickness to prevent condensation. Some climates an inch will work and some climates might need 3 inches. On a metal post and beam construction make sure you have an experienced spray foam guy do the job, if it is applied in to thick of layers it can cause some deformation in the longer open spans. I found this vid because I am spray foaming the roof deck on my build.
Thanks for the video. We just closed on a house in the Seattle area (Marine 4) and our roof is going to be replaced along with some of the sheathing (mold). We need to fix the insulation to help keep condensation out and was considering going closed cell foam so we can use the attic for conditioned storage. How does CCF on the rafters do in the wet environment? I was reading in your comments that vents would be better to not be there. Our alternative is to replace, seal and blow in to R40ish to keep the moisture down, but also read that over venting in the Marine 4 environment will actually cause more condensation. I just want to do the best practice and hopefully avoid these issues. We have a lot more moisture than Regina plus we have 2 skylights that I am worried about the low R causing condensation in the winter.
What do you do for a pitch less than 4/12? I am planning a pole barn that I want to enclose and the roof pitch is closer to 2/12. The roof and exterior will be steel and unvented. Thank you.
My daughter is redoing an old farm house with a non-vented attic. There was no insulation and it is a metal roof. My question is should we add roof vents and spray to attic floor or would you recommend spraying the underside of metal? If you recommend spraying roof what happens if metal needs replacement down the road? Thank you for your videos.
You won't be able to find a leak with closed cell spray foam on the underside of the roof deck. It's just not going to happen. Yes, you may find it after half your roof sheathing rots out. By then it's too late. You're also going to have to condition the attic which means higher bills because you'll need a larger hvac to condition that extra space, or get a separate unit to condition it. If you have to put insulation under your roof deck, put insulation that can be removed and put back. Spraying the entire underside of your roof deck with spray foam is just foolishness. I'm also not prone to believing a company just because they said so. Just because they feel confident doesn't cut it. I respect your argument, but I'm still unconvinced by it.
All of what you said has been proven wrong and refuted. Really you are boring to me... You bring up the same simpleton agreements that have been said many times before and proven false. We have the data to show it and we live it. But just reading what you type I can tell you aren't interested in learning.
What are your thoughts on using a peel and stick for the entire roof deck (for a metal roof) and closed cell on the underside of the roof deck? Would that trap moisture and prevent the sheathing from drying out on either side? Great stuff!
Why use ice-shield on the whole deck in this situation? You can't have ice-dams anyway in winter. And if the metal is done right you won't have a major rain leak. Just use a quality underlayment (not asphalt).
That's exactly how I built my home on the Gulf Coast, (Hurricanes) ICF with metal roof with peel n' stick and closed cell on the underside of the roof deck.
We have cedar shakes on the roof and thus it's vented, using gable end vents. Does the use of the shakes prevent closed cell spray foam from being used on the underside of the roof decking?? Thanks
No not in that limited context of the question. There is not a roofing material that cannot be used with SPF to the underside of a roof. But things MUST be purpose built to achieve the proper end result.
So we went with closed cell on the roof of our house and we are having problems, this was a new house and the design was to always have a non vented roof with spray foam. Our roof wood seems to buckle especially on warmer days, you can see it in the shingles. I believe it was the fault of using the wing underlayment which specifically says not to use on non vented roofs, is a synthetic non breathable underlayment. We are now fighting with the builder to get it repaired, which nobody wants to take blame for.. Does that sound like the scenario of the wrong underlayment being used? Our roof pitch is all 4/12 and higher.
NO. Many other variables. I had a guy try to blame shingles peeling off in a wind storm on spray foam. In fact the idiot that did it - off duty cop - did not use the correct nails. So there are a lot of things people could have done wrong for you. Put on your Columbo hat...
I'm planning on building a metal building home, all metal structure and metal roof, in Louisiana. It is a 2 story home with the entire roof inside vaulted and will be open to the inside of the house. I plan on using 2-3 inches of closed cell, sprayed directly to the metal, on the outside walls and 3-4 inches and the roof. I live 3 miles from the coast and we get lots of rain and sometimes flooding. I'm wondering about mold issues if we end up with standing water inside the house. Will mold grow on the foam? My other questions is the metal roof, what if I get a leak, how would I be able to find it or is this even a concern on metal roof with closed cell sprayed directly to it? I love your videos, they are very informative!
We live in Alabama and are building a new house. We are considering open cell foam. We have an old gas stove, a gas dryer, a gas water heater and want a ventless fireplace. Is this contraindicated in foam houses?
Thoughts on renovation application to a 100 year old plank deck with multiple questionable or moldy areas underside? The drawings seem to apply to new construction with no reference to old homes and integration of vintage and modern practices. Plank spaces knot holes and other openings and less than new kiln dried lumber would seem to pose problems. Sealing in 100 year old low slope 2 x 4 roof and rafters as well. IN those cases would a plywood or other baffle base be warranted to provide ventilation and drying space from underside as low slope roofing does not allow drying from the exterior. I would like to see these legacy home issues addressed directly.
Well....... working on that now. Friday will be brick old buildings and foam. Lots to go over there. I am currently doing the companion video for it on old wood homes. Your answer is already spoken in video #3 of the 4 part series on roofs and SPF. Listen about why we vent inside in the first place.... Fix the questionable areas and then have closed cell SPF installed from the inside. The rest... you will have to watch....no spoilers.
I’m in SoCal, so a fairly temperate climate, and have a garage I want to insulate. It’s all open hip roof, with no venting. Problem is the roof decking is 6” plank boards, not tongue and groove and noticeable gaps. The closed cell spray foam at first looks like a good solution but I’ve seen elsewhere problems with cheap and/or unauthorized shingles for spray foam underneath. Should I stick with foam board instead?
Great info, earned a sub from me. Really like that you give an answer right away then go into details for the rest of the video. Joseph Lstiburek does some great videos that go along with what your saying. Keep up the great content
Do you suggest removing all existing blown in insulation prior to spraying the decking, or can you just pull back around the perimeter. Seems like a waste to throw it all away.
SHINGLE LIFE & SPF Watch our video :: ua-cam.com/video/hJTDvDPtF0A/v-deo.html
Love how you gave the quick answer, and then gave the support… this respects the watcher and allows us to determine what we want or need to watch. Greasy job. And great job on the supporting video.
Thank you.
True. Except, sometimes it might be a matter of whether they want to hear it or not. :D
I retrofitted my 90 year old home with closed cell foam under the roof sheathing. There was effectively no air sealing or insulation there before.
My natural gas usage dropped 50% in December in Ottawa.
This video is making me even more confident.
I love your videos man, especially this one. Straight to the point to those with a low attention span and want a direct "yes or no" but then a full technical explanation. Keep up the awesome job!
Thanks
Excellent video and format, thank you
Yup, we had a large portion of our hallway ceiling collapse because the cellulose took on so much water, then the plaster soaked up so much water. It ever so slightly dropped over the years of the leak and one day just collapsed. The weight of the plaster was incredible.
Leaks are tricky even at best if circumstances. Our house had a roof leak for years but we didn’t known because the cellulose absorbed it until it become a huge leak.
Fiberglass loose fill 7:21 will let water through quickly.
I’ve been using 12/12 and 10/12 pitches for years. We use closed cell foam on our new builds AND we use Huber Wood Zip roofing and Ice guard 4’ up and high quality underlayment. The chances of roof sheathing damage is very very low.
Now, could damage occur one day if the future home owner don’t take time to visually inspect their shingles? Yep. But then concrete and steel eventually erode from neglect also.
I’d the price of closed cell foam was 1/2 it’s current price, I would ALWAYS use it to make our attic spaces un-vented and all our walls and rim joists sprayed over with 3” of
Closed cell and then the balance dense pack fiberglass we use 2x12 rafters and floor joists.
Here is some facts. Energy prices are going to quadruple as the “greenie religion” forces everyone to use electricity only. Better to pay for insulation and air sealing today. Payback isn’t going to be all that many years.
@bret9741 Solar with batteries is now the cheapest way to produce electricity.
Here is a great video comparing coal, gas, wind, and solar.
m.ua-cam.com/video/6_BGHy4sfMs/v-deo.html
We have open cell sprayed on the underside of the roof deck, It was done in 1998. The roofer did a poor job and many nails missed. These small leaks were not big enough to drip below, but big enough we noticed soft spots in the decking. Rather than take the roof off and deal with the soft decking we instead nailed 1x4" perlins through the shingles and put on a metal roof. There is now a one inch air gap between the original roof and the metal. Not only did this solve the leaks but the house is noticeably cooler in the summer. We are in Indiana so summers are very hot.
Good testimony that shows it is NOT the end of the world for a few leaks. People make out like the roof leaking inside the house will limit the damage.
I have seen 5 layers of shingles on one roof.
After 50years Renovations. You see a lot.
Old timers theory was if it leaks and you covered it up to solve the problem. You are only fooling yourself.
The moisture is still in there. Stupid thing like capillary draw and physics-based tell you that if the problem is eliminated then it is solved.
My former 20 year apprentices ousted to have a saying from his grandfather.
"No one can afford to do it right the first time. But they can always afford to do it right the second time. ( after they ripped off what they did the first time after it failed)
Hello Mike and thanks for your very informative videos which were just recommended to me. We have a 30 year old home on Lake Michigan. It has a formed on site standing seam copper roof. The underlayment is Grace Ice & Water Shield (directly under the copper and sticking to the sheathing decking (7/8th plywood). This building has cathedral cedar ceilings and a non vented roof using blown in cellulose. Lightning rods on the ridge cap recently started leaking (broken calk seal) and some of the lightning rods had penetrated the Grace Ice and Water Shield under the ridge cap. This caused black mold on. the interior ridge beam. The fire retardant in the cellulose limited the mold - but the ceiling cellulose near the ridge was wet from condensation. The temperture at the copper was measured at 140F wile interior a few inches away was at 80F.
We are removing all of the ceiling cellulose and replacing it with closed cell foam. The insulation contractor wants to install 6" of closed cell foam (icynene) directly to the underside of the roof sheathing. This would create decking encapsulated by Grace on one side and closed cell foam on the other. There should be no moisture in the plywood but also no way for any trapped moisture to get out. In one of your replies you indicated that this situation should be dealt with using "sheathing membranes".
I did some research on sheathing membranes and it looks like they are just an impermeable vapor barrier?
deltaacademy.dorken.com/resources/the-fundamentals-of-sheathing-membranes-and-air-barrier-protection/
Can I have my contractor spay closed cell foam directly to the bottom of the sheathing? Or we need to stick a sheathing membrane on first then the foam over the top? I really don't want to cut holes in the house to vent the roof because we live right on Lake Michigan and often experience high winds and driving rain and snow (and 18 foot waves)
Lots of information, some want me to create a vented roof by cutting holes in the house and venting the ridge cap because they say the sheathing must be vented to dry and cool. I'm a licensed engineer (not a building engineer) and find conflicting advice.
Thanks for your help.
So are you spraying this from the inside of the house or from outside down? I am not clear on the procedure.
A so true statement just because it is leaking in one place that does not mean that is the origin of the leak.
I really appreciate your approach to these videos. Concise, thoughtful and informative!
After running a renovations business for a little more than 20 years now, I find myself building small-ish cabins for use as long term rentals as well as to sell. Looking to keep my costs low, I have looked to an idea that I used about 12 years ago on my own house build with a semi-vaulted roof system. (Scissor trusses) To obtain the required R value in the heels of the trusses, I was forced to use spray foam. After weighing the costs, I ended up using two layers of 4 inch blue Polystyrene foam insulation attached with quick -forming adhesive and recessed about an inch from the sides of the trusses cavities. Then, I filled those gaps with spray foam and added (approximately) 2 more inches of spray foam over top of everything.
The Polystyrene boards were acquired from another job (re-doing a metal flat tar roof on a Home Depot building) so it saved me some serious $$.
I too thought that insulating the roof deck would be advantageous over insulating the ceiling, and it has been maintenance free ever since.
I was concerned that the minimal contact of the Polystyrene to the roof deck would be an issue, but it has been fine. Roof is a 4/12 with tar paper underlayment and 3 tab asphalt shingles in Edmonton Alberta. Any thoughts on this?
Love your channel - liked and sub'd!😊
The principals are all the same, except you have a tough job trying to repeat what we are. Self-adhering rigid insulation, and conforming to the irregularities of the space created.
Much depends on your diligence to get it well adhered and sealed. Air sealed is the major.
@@SprayJones agreed. I'm always looking to save $$ where I can, but the long term savings of a solidly insulated (open vaulted) roof system far outweigh the higher initial costs. I will do more research for current standards in my BC here, but I remember having to convince the building inspector that the spray foam on the roof deck option was a good and proper way of achieving required insulative values in the roof structure.
I have watched 20 videos and asked about 10 questions. I am finishing my 2nd floor cape in MA with a 12/12 roof with closed cell insulation ONLY. Rest of the house is open cell. I feel 100percent confident that its the right thing to do. I dont know what it will cost but it doesnt matter. I am looking forward to a great envelope protecting me from summer heat and winter cold.
Sounds great!
Great video - thanks! Good to have solid info like this....Ive had many discussions/arguments over exactly this! I Had Closed cell sprayed in my attic roof deck and walls - in a 100 yr old wood stick frame house. It tightened everything up and Ive never had a problem since. It has paid for itself on my heat bills over 4 years.
Thanks for sharing!
Man what an awesome vid and explanation. All any of us want are common sense answers backed by rational data.
Amen.
I think you made a good case @7:30 for not using closed cell foam. Once you encase the roof deck in closed cell you would have no way of knowing if your roof is rotting away until your shingles start to fly off. Sounds like cutting the roof deck with a skilsaw might have been avoided if the leak was detected early.
I like the idea of open cell for that application, closed cell everywhere else.
Just ask a roofer how many times do they have to replace roof sheathing on a conventional roof when they replace shingles? How did the guy in the story I told discover the issue?
The key is if the roofing allows trapped moisture to get out. I would assume most asphalt shingle assemblies will but not nessarily.
If you do have a leak in your roof with spray foam on the underside you will not know it until the sheething, structure has rotted away. As stated, that foam glues everything together, it will be very difficult to replace that. Given that roofing guys often have to replace sheets when re-roofing houses, I would be very nervous putting spray foam on the underside of that decking.
Saying that, there certainly are lot of advantages in spraying the underside.
Google search: BSI-016: Ping Pong Water and The Chemical Engineer
Open-cell is a disaster waiting to happen. Just read the study from that search.
Glad to have that question answered. That made sense. Thanks
Glad to help
I guess you can add that closed cell is IRC code required in the United States for any unvented attic where the spray foam is applied to the underside of the roof deck.
Unfortunately where I live in the south termites are absolutely out of control and you don't find the damage until it's far too late. I have open cell foam and all of my house, but dearly regretted given the circumstances
Just found your channel. Good info. Somethings to mention. Closed cell in this scenario needs to be air tight with no air leaks through to roof sheeting. In my experience, air leaks in cold climates can drive enough moisture to cause structural damage from rot. Also ice dams can be an issue. We've had good luck with using baffles to create 2"+ ventilation space and thus maintain a cold roof while still gaining the advantages of closed cell foam, the added rigidity, the conditioned attic space, much less ice damming and, for me, accessible ceiling systems.
The baffle idea seems like common sense to me and to the installer I've used on multiple jobs but I've never seen it mentioned in any foam industry info. Wonder why?
Do not agree.
@@SprayJones his point seemed logical I wonder why you did not agree. Could you please explain, thanks so much. Also if you have an air gap there if you had to replace any sheathing, it would not interfere with the spray foam.
@@davidhannan2023 The air gap is a fine way to hybridize ventilation while remaining sealed. Engineering tests have been done on this. Google Search: BA-1409: Field Testing Unvented Roofs with Asphalt Shingles in Cold and Hot-Humid Climates
The hybrid method with the air gap between the foam and the roof is what I am going to do on my new roof since I have to replace ALL of it, and I'd rather keep my roof cold in the winter, so it doesn't get assistance melting from inside.
I would assume that now the space is not unvented anymore. This video is for unvented spaces so everthing needs to be ar tight.@davidhannan2023
Absolutely. Matt Risinger utube supports very similar procedure.
And we can watch this video without seeing skinny jeans.
I've seen Matt Risinger spew some extraordinary amount of stupid at times... Just sayin.
We have to have some type of ventilation in attic spaces by code in Michigan. Mechanical or passive ventilation your choice. With proper ventilation your shingles will last longer and not blister up. I have seen house's roof sheeting rot from spray foam and no roof ventilation. Currently ripping out finished spray foam basement. They sealed the masonry. Masonry loves to wick moisture. Condensation built up in blocks over time. Till it leaked in basement. The masonry needed an area above grade to dry moisture out. With roofs the issue is condensation. I tell people to make sure they have roof vent baffles installed before spraying foam.
Watch the video I made on shingle life and SPF.
Then the 4 part series on non-vented roofs.
Code is based on open cell fibrous NOT SPF. So you cannot import misaligned rules to this system.
Half way through my remodel i decided to swtich to nonvented attic with spray foam.
I have a metal roof no penetrations. The plumbing vent goes out the siding near the peak then up above the roof line per code.
If i did it again i would have used zip tape over the rafters to protect from nail holes. I also would have used zip roof deck. Im not a pro builder but i do think things through.
Fortunately i used a metal standing seam roof instead of shingles so my decking ahould stay dry.
They are assuming a 'drying season'. And they are assuming everywhere has that when they say it can be used everywhere as long as the pitch is greater than 3/12. That is just not so. In my particular area which is a temperate coastal rain forest things that wet just don't dry out with our average of thirty days or less of actual sunshine (combined with winds over 100 mph and 170 inches of rain). I am sure there are other such climatic zones in North America. Engineers and architects have a long history of failures so I just wouldn't be comfortable with any blanket statement from them and skeptical of particular local advice. I can show you one failure after another in our small community alone that was caused by bad design from 'certified' engineers and architects. When you combine modern building materials and water you have a large problem. Imagine six months of wet on OSB!! Then add it some freeze thaw cycles.... Spray foam is a good thing in limited situations but allowing a structure to 'breathe' in all but desert conditions is very important. The other new drawback I hear of and see is over the long haul the foam both open and closed 'shrinks' away from the dimensional lumber causing condensation where those openings lead to a cold external surface. I will be much more comfortable when I have seen forty years of existence of any brand of foam used successfully in tough climates. Always and interesting topic.
Do you drive a 40 year old car?
@@SprayJones That is an ignorant reply. A car is not designed with the lifespan or price of a home and in any case proves my point for all the absolute failures the auto industry has foisted off on the consumer. Is that your goal? Get your pile and get out before the failures come to fruition. You use a very poor analogy in any case as it disproves your position. Most car successes were built on a solid years long history of performance while their failures came with no eye on what preceded much as the spray foam in a home phenomenon!
Douglas, I whole heartedly agree with you. I have the same concerns with this application trapping moisture between the foam and roofing. I think it's okay for walls but not roofs. This will also bake asphalt based shingles due to the absence of cooling of solar radiant heat gain, which I have personally seen with SIP panel and rigid foam structures. There is also sick house syndrome from structures being too air tight. Remember, for every action there is an equal and opposite reaction that sometimes is exponentially greater than what you are trying to solve. Not everything "new and improved" is better. I made the contractor remodeling a portion of our camp (I was not the member in charge of the project) put venting baffles in before the foam. I do roof and building envelope inspections an have been concerned about this since it started to be promoted, by you guessed it, the sprayfoam industry.
I think this is a good conversation. @SprayJones comment doesn't help their case.
Using closed cell foam in an unvented conditioned space has a big caveat and could be bad if the roof isn't done correctly. If you have a conditioned attic space then the roof is no different than an exterior wall assembly. If you use closed cell foam on the inside it acts as a non-permeable vapor barrier on the inside. This means that the outside of the wall or roof needs to breathe all the way through your layers of your assembly to the closed cell foam below.
This means no peel and stick water and ice shields on top of the roof sheathing. If you do that then you have your wood roof sheathing sandwiched between two water and vapor impermeable materials. Bad idea since no system ever keeps 100% of moisture out. Very tiny amounts of moisture will get into any system but it will do no damage if it has a very easy exit. That is why any system should only have one vapor barrier on one side.
Closed cell works well for walls because you have a rain screen material like siding that keeps most of the moisture off your outer wall surface with a small gap or drainage plane behind. Then your house wrap is water resistant but vapor permeable. This vapor permeable wrap allows any small amount of moisture that does get into the wall system to get back out once it is stopped by your impermeable closed cell foam.
So closed cell foam for your attic is fine as long as you use a similar exterior system for your roof. Just use a vapor permeable but water resistant underlayment for your roof system.
What type of underlayment and ice shield would you recommend?
Peel and stick the sheathing to seal all the nail holes and control moisture intrusion. Spray a drainage coat before the foam.
My builder said he only sprays open cell because of yrs of experience with both. He's had way more issues, both short and long term, with closed cell. I do know I have leaks and have no clue where the source is. My house stays a consistent temp yr round and my electric/gas bill stays relatively cheap compared to my old house and other people I talk to. My attic is unvented conditioned with 4" of open cell foam.
Sounds to me like your builder has issues with trades... having leaks will wreck anything over enough time.
Great video.. I never understood the logic behind people saying open cell would be helpful in the event of a leak.
Me neither
I'm wondering if there could be a condensation issue in colder climates, if any research has been done how this practice holds up to the test of time? A life long carpenter and builder I think having air flow between sheathing and insulation will alleviate the chances of condensation condensation.
How does the roof dry to the exterior? Most roof papers are not breathable air barriers the same as say a tyvec. If the roof deck is not breathable there is where the problem comes into play. I have been in the insurance industry for over a decade and seen numerous roof systems rotted because of spray foam on the underside of roof decking. And most shingle companies will not warrant the shingles anyway. That is probably why the engineer put that disclaimer in ther
My Dr. hates it when I come into his office with my google PHD and tell him what is wrong and why.
This is not a google reply I have been in construction trade for 30 plus years and the insurance industry the last 11, my response is from seeing it not google. That’s why the engineer leaves himself and out by saying it needs to breathe
@@patholland8835 you are correct . There have been several instances of soft decking and shingles coming off on houses under 10 years old. Hopefully these spray foam installers are held responsible when this all goes south . Closed cell is ridiculous against roof decking, period imo. A lot of this stuff works on paper when the engineer is writing it
We’re the roofs high pitch? That was a requirement
Exactly. Maybe you can get away with it for a while. And closed cell certainly can prevent moisture and/or condensation issues from the inside. And sure, the closed cell might prevent the leaks from entering the living space, but it's also going to cover up a ton of smaller problems over time.
Someone explain this - why is it best practice to use a rain screen siding setup with ventilation, but (apparently) fine not to do it on the roof? The walls are vertical, often have soffit protection, and far less water pressure, plus wall peel and sticks/tyveks/etc generally are FAR more vapor open - but time and time again you find unvented setups that have rotted from water entering at failed penetrations and then not being able to dry fast enough.
You are creating a sandwich of two non-permeable materials with a water sensitive material between on the most exposed part of the house which also happens to have thousands of penetrations from not only fasteners, but also vents/skylights/valleys/etc. Ice and water shield isn't vapor permeable. It's going to hold that water a LONG time no matter what the temp or the sun thinks about it. Closed cell isn't vapor permeable. The only way out is going to be the failed penetrations, open seams, or wicking through the rafters or roof sheathing itself.
I've seen this pushed a bunch of times, but never have I seen anyone explain that.
I feel sorry for roofers and homeowners with spray. Most roof decking needs to replaced at some point, a lot of bad roofers out there. How hard is it going to be to rip that ply off there to replace? It’s going to be super expensive and difficult. Then you’ll have to reinsulate. Traditional insulation in areas that need access for service is a better option long term. Plus, I’ve seen a few bad spray jobs that owners were getting sick
We recently completed a 12/12 pitched roof with the axis east and west for future solar. Direct southern exposure and the plans specified closed cell foam on the underside - no ventilation.
I've been doing this for almost 50 years and the thought of a cathedral roof with no 1" continuous ventilation from soffitt to ridge vent used to be heresy, but now is the preferred method.
I have been in many an attic that is suffocating in the summer heat, and the old 3 tab roofs would literally curl up at the edges like bacon and then a stiff wind would bend them up and over at the next edge. My concern is what roofing can stand up to the south sun with an insulting layer under that allows no heat dissipation? You mentioned 'ice and water' as the underlayment and the specs did note the roofing material needed to be approved for this application. I'm in Seattle, so not so cold and not so hot, but plenty of water.
In addition, our building inspector mentioned the dew point as the main factor in negating the need for ventilation. I have a roof interior coming up for insulating and want to be convinced that this has stood the test of time and I'm just ignorant.
In the 80's we went thru a period of maximum building wrap, sealed windows, caulking everywhere and vapor barrier on the inside, but the exterior envelopes leaked, the insulated walls could not breathe and there were whole blocks of apt buildings requiring residing in less than 10 years. It was a major problem up and down the west coast from Canada to California.
I subscribed and am working my way thru your videos...Thanks for all the info. I know this is part of your marketing but I also know when someone loves their job.
Richard go to the playlist on this channel dedicated the vaulted ceilings. Watch the 4 part series on non vented roofs and the shingle life video I did. That should quell any normal concerns.
I put closed cell up 20 years ago on vaulted roof around 1.5 inches never had any condensation i can say for sure because much of it is unfinished to this day I'm in Chicago area. Before i put up any foam I waited for some heavy rains to make sure no leaks. If I were to do it over again I would use ice and water dam from bottom to top. I did have a woodpecker make a hole in the wall one sheet of OSB damaged about 2 feet by 4 feet spot to fix and I scraped the OSB off the closed cell foam without damage to foam. This foam won't hurt any shingles.
@@portagepete1 thanks for the vote in favor,
my wife wonders what takes me so long to decide...but I just watched a pros and cons (mostly cons), and the #1 issue was flame retardants (mandatory). Any bad smells allergic reactions,..cancer ?
I know this video is two years ago but I am just getting into the spray foam world. Had lots of people talk about needing to install some sort of roof baffles or some sort of ventilation. From watching this video it appears that that is not the case, correct. Spraying UPC 2.0 foam, living in Palmer Alaska. Thanks!
Watch the vaulted ceiling playlist. There are a lot of videos there to get educated on.
Closed cell on the bottom. Peel and stick or fluid applied on the top you I’m pretty sure you will NEVER have a problem. Thoughts?
Agreed.
People that have issues have chosen cheap products, installed by morons, because of the bottom dollar was good.
I keep hearing conflicting info on putting foam directly to a roof deck. Some people insist you need an airspace there to keep the roof deck cool.
You do not. Commercial roofing does not use an air space between a deck pan, rigid and a top membrane.
It's time to break out of 75 year old technology and the dogmas that go along with it.
True !
I had multiple spray foam installers (got three quotes) tell me it was fine. My roofers wanted vents, I told them I was spraying to the roof deck - they checked with the shingle manufacturer to ensure they would be able to offer a warranty before they even started on the roof (wasn't a problem). I then checked with my Hydro rep (when I was having my house assessed for energy efficiency grants) and he stated that a vented roof would actually lead to more problems and the only reason that it's still sometimes done is because building code is lagging behind the technology. Same reason the spray foam guys actually told me there was no point in spraying more than 4" of foam on a roof or 3" in a wall but code may still require it because it's based on fibre glass batt R value (or did when I had my house sprayed and inspected). As a result they had to spray 4" on my basement walls to pass inspection even though they said there was negligible returns going from 3" to 4" on a wall. My only concern was the point brought up earlier, that if there was damage to the roof you would never know about it because the water would take a long time to go around the foam to get into the house and show itself. That's where investing in a proper roof comes in - get the membrane, get the ice and water, get a company that does it right.
Recently had open cell sprayed in my attic. Noticed a leak during a rain storm shortly after due to the expanding foam pushed off our ridge vent. I had all 3 ridge vents removed and shingled over the opening. Problem solved but it cost the spray foam company $675 for this work. Ridge vents should be removed prior to spraying.
They should be covered up from the inside so the foam doesn't go into them. Same result.
@@SprayJones True, either way works i guess. Thanks for sharing!
Can you use close cell on 1/12 pitch metal PBR roofs.( in south east US)
Have perused your vids but can't find anything spacific. Thanks for your ethics's just wish ALL spray foam contractors had your integrity and desire to educate others.
As for as I'm concerned that is what transparency is meant for.
Great vid, very helpful. I'm embarking on a closed cell job for my roof deck. Two quesitons if I may!
1.) Is adding stregth to roofdecks for snowload a universal benefit when applying at least 4" of closed cell?
2.) We just completed some sistered rafters to the attic roofdeck. New lumber to old rafters. Should the new lumber be dried to a minimum moisture before spraying foam?
I don’t know why I can’t stop watching your dam videos.
They are blessed, not damned... Lol
I believe one important Building Code detail... as Part 9 of the NBC is being cited... you don’t mention is the requirement for a vented air space between the top of the insulation and the underside of the roof sheathing. I’m not saying SPF cannot be installed in this location.
However, since no vented air space is being provided and most jurisdictions (Cities) must follow the prescriptive Acceptable Solutions listed in their Provincial Building Code, the use of an Alternative Solution may be required.
I highly suggest the local Building Inspector is consulted before SPF is installed to determine if an Alternative Solution will be required.
You are correct. For the last 12 years this has bee placed to bed. The Province reviewed this and has approved it. You have to apply with your SPF paper work at the time of permit and then it will be granted. There aren't too may places that have an issue with this.
Your videos have helped convince me that an unvented condition attic is the way to go. We are going to put new asphalt shingles on just prior to spraying closed cell foam on the rafters. What kind of underpayment should we use?
That is your roofer. I do not know.
Pick the BEST SPF contract you can. Vet them out and do not be afraid to pay for it. Less issue potential.
I live in the south and have an older house. I have a ridge vent and side draft exits, do those stay? Can i also leave the blown in insulation that's already there on the floor? Would you recommend closed cell?
I live in AZ and also wonder if I used closed cell do I need to remove existing blown in insulation and block off my attic vents. Also do you need to have the attic ventilated with your hvac also
Just wondering what you guys ended up doing? I have a similar situation. Thanks
I would assume a roof with lower than a 3 pitch would have EPDM or greater roof covering and would allow for the same /similar detail.
It would be the same. Vulcanized roofing over the top.
The other safety factor is to install roof wrap. On the roof. Usually a water repellent membrane. Before the shingles are applied.
This video is better than you even realise... Closed cell simply does not absorb water.
This is a question I've had for since I decided to go spray foam. Thanks.
Glad I could help!
Building Science Insights: To Vent or Not to Vent watch this he is an authority
Thank you for making this video. Exactly what I needed.
Top shelf educational vid ... thanks again for these thorough vids and explanations
What about 4:12 or greater invented metal roof with high heat peel
And stick underpayment as a roof
In Florida.
Was looking at 2”closed cell
What about open cell for the underside of an EPDM flat roof? I assume this means the roof assembly needs to dry to the inside during all seasons which requires proper HVAC maintaining low RH in the dwelling.
We treat EPDM flat roofs on a case by case basis to review all variables and liabilities. In short we have sprayed all that we have done with closed cell because it was the right fit for the inside.
Let me be clear: YOU ARE CORRECT. What is amazing is that here in florida they STILL buy into the myth. At least the folks I have had over to my home for spray foam quotes.
Have you ever spray foamed gambrel roofs? Would like a video in that maybe talking about pros and cons
Keep in mind that roofs with a 3:12 pitch require two layers of asphalt paper under the shingles. I would be very careful about using closed-cell on less than a 4:12 pitch.
What you fail to understand is that the closed-cell foam provides a moisture barrier under the plywood (like a vapor barrier). So any water that makes it to the plywood will be trapped between the ashpalt underlayment (which is a vapor barrier) and the closed foam insulation. This will impede the plywood from drying out. So your assumptions that all water will just drain off are incorrect. All water has to do is get under that asphalt paper and soak the plywood. This can happen if the roof is not sheathed and flashed correctly. The advantage of a vented attic is that if water does get to the plywood, the plywood can dry out from underneath air in the attic. That is a key difference.
Putting in closed cell insulation in the roof can be done safely and it is a great insulation system, but if human error comes into play, it can rot large sections of the roof before it is discovered and that is why it is not widely used. Presumably, if water got under the 15 lb asphalt paper and soaked the plywood, if open cell foam insulation was used, then the plywood would have a way to dry out.
What we are talking about here is what happens when their is a roof failure. The closed-foam system can greatly increase the scope of damage caused by a roof failure. Also remember if the roof is a tile roof, then the cost of repair can be significant.
Thanks Frank. Stay subbed, I will be doing a new video on vaulted roof systems and SPF.
Question. Is there an advantage to 1" of closed cell followed with 3" of open cell? As opposed to only 2" of closed cell? Some installers are recommending this application mainly due to cost of material. THANKS!
You mentioned a resource indicating it was safe to use CCF under roof decks on 4/12 or greater shingled roof…..
What about low slopes roofs. Say a 2/12 roof using 45 mil TPO membrane ? Typically residential manufactured homes with TPO roof membranes are not glued down.
CCF would be great for strength on an older structure, but what about future roof leaks?
I should say this is in Florida. My home was narrowly missed by hurricane Ian.
Local SPF installers need to have their engineering done with state valid firms.
You have to source that locally. But it is NOT as hard to find as you may think.
You can't use asphalt shingles. They seal eachother in with tar strips. They are referring to cedar breather and cedar shake roof shingles that allow moisture to condense and evaporate from under the shingle back into the outside air. Otherwise you need a vent beneath the shingles making the sheathing the shingles are attached to the same temperature as the air outside
No you do not. Please get off here if you are spouting uneducated nonsense.
We have been doing this for 17 years, and we are nowhere near first in the industry.
This poster is correct. Asphalt roofing systems create a vapor barrier.
www.owenscorning.com/NetworkShare/Roofing/10013915-Deck-Defense-Technical-White-Paper-October-2011.pdf
Joseph Lstiburek is one of the authors so don't let the Owens Corning web site lead to a different conclusion.
Can you use 2" of closed cell then fill gap with open cell? I have an I.C.F home basement, and 2nd floor 3rd floor is a mix of 2"x12" walls and 2"x6 walls ,I'm going to have a condition attic that is cathedral type , the contractor I'm looking to use is recommending open cell with the thought that a void in the 2"x12" wall area and possibly the 2"x6" wall will create a bad echo ??
They said it needs to be able to dry to the outside. Does that mean there are situations where you can’t do a mental roof and spray foam?
Does this hold true for metals roofs as well? I have an 8/12 pitch on a new build and have ice and water the entire roof prior to metal going on. No strapping between roof deck and metal. thanks. In Quebec (cottage).
I'm an engineer and I agree that this is ok but using an explanation of "because an engineer says so" is just circumstantial inference and not a technical defense. I would have liked to see the technical explanation included. I know there are minimum thickness requirements based on location to prevent dew point condensation and different things like that.
I don't go into overly technical explanations. No one wants to watch that and the time to make the video does not pay off with views or ads run. So I keep it simple.
So if closed cell was applied, I’m guessing you wouldn’t use any iceshield beneath the shingles? I can see the inspector challenging this lol. At the same time, although I completely agree with your argument, one would never really know when there’s a breach in the osb sheeting, beneath the shingles.
What you do exterior is not much of my concern. I see no reason not to use the ice-shield, it changes nothing for the envelope on the inside.
@@SprayJones I wonder, though, could you have a problem with water seeping through the plywood to the bottom and have no where to go and get trapped top and bottom, or should you use an ice shield but leave some less water tight area at the very bottom in the eaves?
Wow, I love your video. Only problem is that I saw it too late. We just had our roof replaced with aluminum shingles. The underside of our roof sheeting is insulated using closed cell spray foam. The Installer claimed that he could not put the Aluminum Shingles directly on our existing plywood. He took off our old shingles and weather barrier and add a false roof over our 12/12 sloped roof. And in doing so he neglected to raise the flashing around our cultured stone chimney. As a consequence, to his actions, we now have water entering our home where the closed ends at the lower edge of our roof. My question is could aluminum shingles (which vent extremely well) be placed over a roof that has been spray foamed?
did 4" of closed cell and that stuff is so strong that i feel like the house almost doesnt need sheathing.
Well in my local building code change this to you can't use closed cell on roof underside and encapsulating the rafters. The reason being there was one or two roof collapses because of a poorly maintained roof and the leak over decades had rotted the sheathing and rafters and there was no signs of a leak inside, so no one checked. You can however use open cell because once the foam gets saturated then it would be visible inside that you had a leak and would then go up and inspect the damage and make repairs, plus it was a good idea to replace or dry out the damaged foam. Also our snow load where I live is 62 lbs per square foot which is also a factor. You say these engineers certify that product under those applications, well sure they would, but a poorly maintain roof would not have a bearing on that certification, that's on the owner to ensure their investment is protected. So I guess one or two dummies wrecked it for the rest of us.
That's no good. Someone need to take a lead with a supplier and building envelope firm and get that changed. I would if I was there...
I have one stupid last questions. I promise this will be my last. I am following as I understand it your advice. 2" closed cell on my foundation slab, 2-2.5" in my wall assembly (I will have Zip R-6 a sheathing), 3" closed cell on roof deck in my conditioned attic. So here is my stupid question. Should I also go 2" of closed cell between my ceiling and my conditioned attic? I am sure the answer is yes, but trying to cut some cost and just don't know. If my attic roof deck is closed and my walls are closed, is it worth doing in the ceiling of my ranch home? Thanks, sorry for asking so many questions, but I trust your opinion.
If you have sprayed to the roof deck you do not need insulation on the drywall ceiling. It is hanging in mid space...
For the record my suggestions are subject to code approvals for your area....
@@SprayJones Thanks. I just got a quote back from a contractor. I am pretty shocked. In short here is the details of the quote. Heated and Cooled square ft. 4,300 12 ft interior ceilings. I asked for the following. 2" closed cell foam for the slab. 2-2.5" on all interior wall within the heated and cooled space. 3" closed cell foam on the roof deck within the conditioned attic space. 4" open cell ceiling that is the garage ceiling to the conditioned attic. Total Bill 73,000.00 for the job. I am shocked to say the least.
Awesome
Videos you’re doing your community a great service thank you! Question- when you talk about the case with the man with the 12/12 pitch going to the 4/12 and water getting underneath the shingles… why would they have had to apply more spray foam when doing the repair? Wouldn’t the old closed cell foam remain undamaged and flat against roof deck so that the new piece could simply been placed flush right over it?
They chewed up the foam when they did the repair. Common issue really.
You are an awesome tuber, THANK you for getting to the point strait off, for those who just want tje answer you did us a huge service. Ill subscribe for that
Wow! Right on. Thanks
I noticed that you sprayed the complete 2x4 even on the bottom for the ceiling. Does this need to be done in order to make it all vapor proof? I am having my addition spray foamed with the following. Rafters are 2x12" 12" on center. 3" closed up to the roof deck then an additional 4.5" of open cell. So this leaves the bottom of the 2x12 not sealed. Should a plastic vapor barrier be installed. Have not talked to the contractor about this yet. Project site is in central Massachusetts
You have some technical questions that need answering. Talk with your contractor.
Closed cell foam is a vapor barrier.
Man I love your Channel.
Great information right to the point and I can tell with alot of experience. Thanks
I appreciate that!
Seems like it's a condensation point seems like a bad deal We're the warm and the cold touch It will condensate
I seen metal buildings with flat roofs which spray in foam insulation if I built a metal building I would do this spray in Foam and insulation and I would cover it all up with metal It's a metal roof if you can't find a hole in a metal roof you do not belong on that roof please comment back if I am right or wrong thank you I used to do roofing for many years burn down rubber roofs Hot roofing jobs And also shingle jobs I used to find the holes in the hot roofs and the burn down rubber roughs before I found the shingle week a less it was a single missing or just a natural HOL E in The Roof or a less it was in the valleys or around distinct pipes or around the chimney every so many years you're supposed to go up there with a bucket of gunk and re do them thank you for this video
My neighbour just had open cell foam installed - I'm located west coast Scotland very wet, damp, humid conditions most of the year, wettest and windiest place in Europe... Closed cell sounds better to me... Can you tell me about off gassing with open and closed cell please, you seem to know your stuff, thank you in advance.
Would a standing seam metal roof further decrease the potential leaking consideration?
Over shingles? Sure, but all things come down to installation excellence.
Great video! Just the info I needed. One question: see any issues using zip system roof deck and closed cell under?
Not at all. But get some pros in your corner when making final decisions. Ones that understand foam and not old ways.
Jury is still out on this as it is too new. Engineers are wrong a lot as everything works on paper. Every hot roof I've encountered have moisture retention issues. This will cook shingles but not affect metal, tile, or slate. Will probably cook synthetic slate. Buildings need to breath or you get sick building syndrome.
1. This has been around for 30 years already
2. Engineering has shown this to be a proper method
3. Building codes support it
4. Shingles last just fine with SPF
5. Commercial BUR roofing does not vent, how is SPF different
You comment ignorantly instead of learning.
@@SprayJones so you insult rather than listen to a different point of view, speaks a lot about your character. I've been roofing since 1980 and now troubleshoot and assess problem roofs. I see on a daily basis issues with unvented roofs. BUR is a completely different system that typically uses different insulation and is not as common today as single ply or mod-bit which usually use rigid foam and fiberboard. I have personally seen shingles turn to potato chip consistency from insulated sheathing. Go sell your product like a used car salesman.(insult intended right back at you). Shingle manufacturers require vented roof decks, read instructions and warrantee requirements.
What about a flat roof with modified bitumen torch down roofing? When they're talking about three and twelve they're specifically referring to using shingles, right...?
What an amazing explanation!
Glad you think so!
Best overview on the topic..thx😊
Glad it was helpful!
You address a shingle application, what are your thoughts about a steel roof at 3/12 with closed cell? Thanks
Hello Mr Jones: I have a couple of questions.. I'm having a new all metal building put up.. The beams, girts and trusses are galvanized, do l need to prime them with something prior to spry foam? #2 How thick should the foam be on the under side on the roof? Non vented roof.. Thank you.
I like to prime galvanized when I am applying to large panels made of the stuff.
I have a small leak from a solar rack and the closed cell has ultimately kept a ton of water out. I have been trying to get a contractor to simply fix the roof and it is a nightmare!
Thanks for the feedback. Why do people want water to come inside the building so they can see it and have more compounded damage is mind-boggling.
@@SprayJones yup got a pan under it. No one wants to come out and deal with thr panels. It isnt like it is a small job i want them to cover a couple of intrusions and replace done shingles. I might as well go up and do it.
@@K0gashuk0 Find a handy siding and exterior contractor. Make friends, they have all the skills of roofers. Plus all the safety gear for getting up. My dad fell from a ladder getting onto the roof that ended his life at 57.
Thank you for your videos! I enjoy learning from you! Would this also apply to a metal pole building? I want to have the walls and inside roof metal sprayed with closed cell foam, but I am concerned about ventilation. This building will eventually have heat, but no A/C. Do you have a video already on this situation that I may have missed? Thanks for your assistance!
This is an older video, so you may not get a response from the author.
I am preparing to build a house and have done much research into spray foam.
If you use closed cell spray foam, make sure to get enough thickness to prevent condensation. Some climates an inch will work and some climates might need 3 inches.
On a metal post and beam construction make sure you have an experienced spray foam guy do the job, if it is applied in to thick of layers it can cause some deformation in the longer open spans.
I found this vid because I am spray foaming the roof deck on my build.
@@charlesarmstrong3536 Thank you sir! Much appreciated!
Is it 3:12 and up or 4:12 and up? In the beginning you said 3:12 but at the end you said 4:12.
Can you do a couple layers of Closed Cell Spray foam as the vapor barrier and finish up with 2 or 3 layers of Open Cell Foam
Only if someone has the stats on that to prove it out.
Generally yes.
Thanks for the video. We just closed on a house in the Seattle area (Marine 4) and our roof is going to be replaced along with some of the sheathing (mold). We need to fix the insulation to help keep condensation out and was considering going closed cell foam so we can use the attic for conditioned storage. How does CCF on the rafters do in the wet environment?
I was reading in your comments that vents would be better to not be there. Our alternative is to replace, seal and blow in to R40ish to keep the moisture down, but also read that over venting in the Marine 4 environment will actually cause more condensation. I just want to do the best practice and hopefully avoid these issues.
We have a lot more moisture than Regina plus we have 2 skylights that I am worried about the low R causing condensation in the winter.
Please watch my 4 part series on nonvented roofs. All of your questions will be covered in detail in that learning session.
What do you do for a pitch less than 4/12?
I am planning a pole barn that I want to enclose and the roof pitch is closer to 2/12. The roof and exterior will be steel and unvented.
Thank you.
Steel you spray it just the same.
We do all pitched 1/12 and up.
Should I spray foam my flat roof? Its 2x6 joist with existing shingles
Exactly the evidence.. Information i was looking for. Thank you
Will look into it more
Glad it was helpful!
My daughter is redoing an old farm house with a non-vented attic. There was no insulation and it is a metal roof. My question is should we add roof vents and spray to attic floor or would you recommend spraying the underside of metal? If you recommend spraying roof what happens if metal needs replacement down the road? Thank you for your videos.
In northern New York on Canada border.
Direct to metal.
Please watch parts 2-3 of the non-vented roof series. All your questions are answered there in detail that you will want.
You won't be able to find a leak with closed cell spray foam on the underside of the roof deck. It's just not going to happen. Yes, you may find it after half your roof sheathing rots out. By then it's too late. You're also going to have to condition the attic which means higher bills because you'll need a larger hvac to condition that extra space, or get a separate unit to condition it. If you have to put insulation under your roof deck, put insulation that can be removed and put back.
Spraying the entire underside of your roof deck with spray foam is just foolishness. I'm also not prone to believing a company just because they said so. Just because they feel confident doesn't cut it. I respect your argument, but I'm still unconvinced by it.
All of what you said has been proven wrong and refuted. Really you are boring to me...
You bring up the same simpleton agreements that have been said many times before and proven false. We have the data to show it and we live it. But just reading what you type I can tell you aren't interested in learning.
What are your thoughts on using a peel and stick for the entire roof deck (for a metal roof) and closed cell on the underside of the roof deck? Would that trap moisture and prevent the sheathing from drying out on either side?
Great stuff!
Need a diffusion open membrane. It is simple to source and have installed.
Why use ice-shield on the whole deck in this situation? You can't have ice-dams anyway in winter. And if the metal is done right you won't have a major rain leak. Just use a quality underlayment (not asphalt).
@@SprayJones could you provide an example of this style membrane please?
That's exactly how I built my home on the Gulf Coast, (Hurricanes) ICF with metal roof with peel n' stick and closed cell on the underside of the roof deck.
@@CougarLand Because the ICE Shield does not blow off in a Hurricane.
We have cedar shakes on the roof and thus it's vented, using gable end vents. Does the use of the shakes prevent closed cell spray foam from being used on the underside of the roof decking?? Thanks
No not in that limited context of the question. There is not a roofing material that cannot be used with SPF to the underside of a roof.
But things MUST be purpose built to achieve the proper end result.
So we went with closed cell on the roof of our house and we are having problems, this was a new house and the design was to always have a non vented roof with spray foam. Our roof wood seems to buckle especially on warmer days, you can see it in the shingles. I believe it was the fault of using the wing underlayment which specifically says not to use on non vented roofs, is a synthetic non breathable underlayment. We are now fighting with the builder to get it repaired, which nobody wants to take blame for.. Does that sound like the scenario of the wrong underlayment being used? Our roof pitch is all 4/12 and higher.
NO.
Many other variables.
I had a guy try to blame shingles peeling off in a wind storm on spray foam. In fact the idiot that did it - off duty cop - did not use the correct nails.
So there are a lot of things people could have done wrong for you. Put on your Columbo hat...
I'm planning on building a metal building home, all metal structure and metal roof, in Louisiana. It is a 2 story home with the entire roof inside vaulted and will be open to the inside of the house. I plan on using 2-3 inches of closed cell, sprayed directly to the metal, on the outside walls and 3-4 inches and the roof. I live 3 miles from the coast and we get lots of rain and sometimes flooding. I'm wondering about mold issues if we end up with standing water inside the house. Will mold grow on the foam? My other questions is the metal roof, what if I get a leak, how would I be able to find it or is this even a concern on metal roof with closed cell sprayed directly to it? I love your videos, they are very informative!
Mold will not grow on closed cell foam. Mold needs an organic surface to grow on.
We live in Alabama and are building a new house. We are considering open cell foam. We have an old gas stove, a gas dryer, a gas water heater and want a ventless fireplace. Is this contraindicated in foam houses?
Thanks for your videos, great information without the bs.
For sure.
Thoughts on renovation application to a 100 year old plank deck with multiple questionable or moldy areas underside? The drawings seem to apply to new construction with no reference to old homes and integration of vintage and modern practices. Plank spaces knot holes and other openings and less than new kiln dried lumber would seem to pose problems. Sealing in 100 year old low slope 2 x 4 roof and rafters as well. IN those cases would a plywood or other baffle base be warranted to provide ventilation and drying space from underside as low slope roofing does not allow drying from the exterior. I would like to see these legacy home issues addressed directly.
Well....... working on that now.
Friday will be brick old buildings and foam. Lots to go over there.
I am currently doing the companion video for it on old wood homes.
Your answer is already spoken in video #3 of the 4 part series on roofs and SPF. Listen about why we vent inside in the first place....
Fix the questionable areas and then have closed cell SPF installed from the inside.
The rest... you will have to watch....no spoilers.
I’m in SoCal, so a fairly temperate climate, and have a garage I want to insulate. It’s all open hip roof, with no venting. Problem is the roof decking is 6” plank boards, not tongue and groove and noticeable gaps. The closed cell spray foam at first looks like a good solution but I’ve seen elsewhere problems with cheap and/or unauthorized shingles for spray foam underneath. Should I stick with foam board instead?
No, SPF is the way.
Watch the 4 part series on roofs to know more...
things change over time do they still maintain the same stance? 2008 is a long time ago..
Your reference stated shingles. Are there objections to roof steel directly to the roof deck with closed cell? Or are perlins required?
I am not following you on you install ideas. Purlins are a structural question not a thermal envelope one.
Great info, earned a sub from me. Really like that you give an answer right away then go into details for the rest of the video. Joseph Lstiburek does some great videos that go along with what your saying. Keep up the great content
Thanks for the sub!
Do you suggest removing all existing blown in insulation prior to spraying the decking, or can you just pull back around the perimeter. Seems like a waste to throw it all away.
Has to be removed. How are going to get around and work?
What is the best way to spay a cathedral ceiling with a metal roof? Is it better to strap it for the roof or plywood then spray it?
Plywood, underlay then metal on top.
SPF to the underside of the plywood.