I was a insulator (Residential) in the late 80's and early 90's & when I started the standard was R7 in the walls "with plastic" R19 floor & 30 in attic, when I left & went on to a different profession it was still the same orher than we were using R15 in the walls without plastic, I'm in N.C Raleigh area. It's amazing how far the industry has come. And I have to add I've been around construction & builders my whole adult life about 40 years & you my friend are a hell of a builder, I would love to have you build me or anyone in my family a home, I could rest knowing it was done with integrity.
It would be nice to see insulation reviews start to show and include just how effective cork can be. Also, cork has many benefits to the environment. Is renewable, carbon sink, water resistant, vapor permeable, is almost perfect as insulation.
That foam is no joke. Used it to insulate around some old loose vinyl windows and the foam locked the windows in place better than the screws and blocking did.
No kidding was replacing a door and frame that was sealed with a foam and fastened with bolts, so I unscrewed all the bolts I could find and cut with a power saw from all around the frame and still needed two of us to push the frame with the door loose.
No joke is right! Commercial insulator came in and did kitchen, under floor and under a crawl space. Later, didn't realize I could not set the outlets back. Thankfully the tile backsplash was thick enough that it didn't affect the boxes sticking out max. Make sure that anything needed to set (outlet depth on adjustable boxes, etc) is done BEFORE spraying. Also made mistake on not adding layer of roxul before the sheetrock went up, and ceiling. But so far, temps are good but would like to noise reduction benefit. Next home...
icredibly well informed. Rockwool is incredible for sound and batt. I have bought from IDI...Good company. You hit the spot with just enough for each application. Too many times the builder or homeowner is not interested in foam because they think they need an r-49 cavity foam filled....7" is overkill. 3" is max. You are spot on brother. And your exterior wall design is interesting. That wind blowing hard in the background was a great sales pitch on the foam too....Awesome video. I just came across it.
OK, this answers my (and others) questions about the closed cell foam install. Now this brings us to the next question. What is the upcost of this wall (the 2x3 (5.5" wall thickness) heat break, Zip sheathing, foam, Rockwool) vs a "code" wall (for that area) and how does it compare (costwise) to, a comparable (R-value) ICF wall. If the ICF wall is cheaper, then how much more R-value can you add for the same cost? Love these shows! Please keep them coming!
Minnesota built home here. Cant stress enough put enough foam 2"+ and CONTROL THE MOISTURE through the entire build if its happening through the winter. I neglected to do so and had a lot of condensation occur between the flash and the batt when we had our extreme cold snap which occurs once if not twice a winter. Matt if you read this please look to mentioning it, because its still relatively new concept many aren't aware of, and it can be extremely scary situation. In my case all of it dried out as designed once it warmed up a bit and I dropped the moisture levels as much as possible.
What was the exact assembly? Poly on the interior or something like smart membrane? A flash coat in cold climate can be a risky assembly if not done right.
Controlling moisture is hardly a new concept since polyethylene sheets have been standard in northern walls for close to 50 years. What is new is the realization that even in the north, it might be hot and humid outside while the inside is cool and dry (due to air conditioning), so interior poly isn't a good idea anymore.
In South is enough open cell for walls and roof.We used to spray closed cell the sub floor /freezers. Closed cell is good for vapor barriers and R value, open cell - R value and sound . Cold states : roof - first closed cell ,then open , Sub floor - open cell first , then closed .
I own 2 houses next door to each other, almost identical in layout, one built in 1908 & other 1910, both houses I redid the 3rd floor (complete gut). 1st house is ours & put in Rockwool with polyiso board on the inside (R-6 with drywall to go over it). This reduces thermal bridging through ceiling joists. Next house did closed cell foam between ceiling joists (both houses have roof above it). Considering the performance & price I would definitely do the Rockwool/polyiso combo. Probably half the price (with my labor) & I think it performed better. Again, exact same 3rd floors, next door to each other so a pretty good comparison. Close cell spray foam was about $6k for just the 3rd floor ceiling/walls.
Your Videos are really educational I’m an air-conditioned contractor in Louisiana I love the way you explain everything you’re a great contractor, I would love for you to build my home !
first time someone else besides Spray Jones has said how to do a proper flash and batt! good job. rule of thumb though without looking it up is over 2/3rds ratio. so R14 of closed cell means you should only do a max of R8 in batt form which of course isnt really a product anyone sells. youre better off just doing the 2-3" of closed cell and calling it a day.
@@dovahkindragonborn9827 but pay for that massive R value in closed cell then. keep on packing that R7 in there vs doing more labor and spending for only an R3.5.
we're building a custom walk in cooler for a taproom in Philadelphia. Trying to figure out the climate zone and where I need the dew point to be/or if I even need to worry about one. It's a conditioned space inside of a conditioned space. That being said, very helpful video!
hey matt I want you to talk about the final process of a build. what the contractor usually does before handing it off to the client. window cleaning! I am a window cleaner construction clean ups are a regular part of the job. id even love to clean your windows myself when the time comes.
Hi Matt, great vid as always Just a question re the vapor barrier, if the closed cell is a VB and the ZIp system is a VB, then could this result in a vapor trap for the wood in the zip system?
T-Studs are kiln dried. check the moisture content on yours b4 u install. Not a problem if u have "no open in-wall cavities". If you have "open in-wall cavities" allow for in-house air to circulate.
Indeed. For what looks like a 50-85F average yearly swing, R32 seems overkill. You are only asking your HVAC for a delta of 20F. I guess he's well prepped for the next storm.
@@joshpit2003 since you bring that up, will his HVAC units perform well? like not short cycling etc and fail sooner since they dont get proper run time?
@@joshpit2003 Yes, for Austin, R32 walls are WAY overkill and stupid expensive over what you get with just 2x6 walls with pink stuff. But overkill and expensive never stopped Matt from taking it for free and advertising it for his sponsors.
@@billlan0 Hmm, solar. There's another poor use of dollars. At the electric rates in Austin, it takes 20-30 years to break even vs. on-grid power (just in time to replace the worn out system). This is true unless you take the subsidies which are paid for by your neighbors.
@@neckofthewoods24 He'll be totally fine. They're won't be any short cycling in his ac. So much ai, learning, temperature modeling it'll turn on for awhile to get to temperature and not turn back on for quite awhile. He's going to size it appropriately. If he goes too big of a unit what you're saying could happen.
Sound will go through electrical boxes. Here in Russia Acoustic group produce sound reducing electrical boxes for drywall. Sure they are for European DIN standard.
Thank you so much for this video. My framing (100 year old masonry block house balloon framed house) is offset by 5" from the exterior block wall for structural reasons. We're spraying 2" of ccSF on the block. Then I want to add batts. My question is do the batts need to be thick enough to fill entire gap from the foam to the drywall (as much as 6.5") or can there be a gap between the ccSF and the batt? Or can I put 3.5" rockwool batts on top of the ccSF and leave the gap between the rockwool and drywall? Help!
We are purchasing a home built in the 80s in the north houston area. What are the rules when doing the attic with the closed or open cell foam? As far as AC equipment, venting, etc
Zip is made from OSB. Which is very prone to water damage, regardless of what manufacturers claim. Since the zip is backed with a closed cell (vapor barrier), the idea is that the vapor open (outside surface) is necessary in order to allow the OSB to dry outward in the event that water makes it past (which it will, from over-driven fasteners, constructions scratches, and poor tape-jobs).
@@joshpit2003 surprisingly huber zip OSB is pretty resilient to if left outside. I have a test board Ive left outside over a year explode to rain and sun and while noticeable greying/bleaching no bulging or degradation.I suspect they are elevragign their research nd manufacturing they've had so much success with re advantech sub flooring.Now admittedly my test board is drying optimally and no exposure to standing water, but hell, most PT wood wont stand up idneficntley to standing water.
@@joshpit2003 I looked up the product data. The Zip sheathing itself without the insulation is 12-16 perm, which is very Vapor open. But the insulation is less than 1 perm. I agree with your comment that the vapor openness is to counter any water intrusion from outside potential through compromise in the factory applied water/vapor barrier by fastener holes and etc. However, this is not supposed to be used if the concern is more for vapor drive coming from the inside, such as compromised vapor retarder in a northern heating dominant climate. What Matt is doing here with vapor closed spray foam in Texas would have no issue. But you probably want to avoid this assembly in northern climate, due to the vapor closeness of the whole assembly. The best would still be exterior insulation with some batt insulation that keep the sheathing in the warm side, with vapor open assembly to allow vapor drive outwards. Correct me if I am wrong.
At about 8:55, Matt discusses MW printing the R-value on the batt. During the install R15 was placed on the lower section and R13 was placed in the upper section. Was that a specific design decision or a quality control issue?
Matt we are in the middle of a remodel and can’t find a straight answer. Our house is 105yr old in a dry California climate. It was built with wood siding, a felt layer, and 1/2” wood sheathing. It doesn’t have a vapor barrier do I need to add one or use hard foam insulation before putting in Rockwool? What would be the best way.
In northern climates, isn't it common to seal as a last interior later before drywall with a layer of plastic sheet (or some equivalent) to prevent condensation? Many northern assemblies don't use spray foam, but that seems to be suggested at 4:00 - 6:00. I thought in northern climates we dried to the outside, which spray foam might actually complicate in an imperfect assembly.
Up north where I am in Canada they did require a vapor barrier sheet before the drywall, and the spray foam had to be covered with fireproof insulation. This a was in a basement. I wouldn’t leave out the interior vapor barrier even with the spray foam, it gets to -40F here, you want all the condensation protection you can get.
Even in northern climates hot and humid summers are common, so the interior plastic sheet can make the condensation problem worse. Spray foam based assemblies don't need to dry, since no surfaces that water vapor can reach will ever be below dew point.
One thing I most definitely like about UA-cam, sort of like the books or magazines of old (of which I do not buy or have any more), is that I can refer back to them (haha... if I remember where they might be, but so to was the case with books and magazines, but at least now I have an intelligent(?) search engine). Currently I do not know what is in my house's walls, but I know there is nothing in my floors for I having a house with a crawl space and having inspected that visually. (Sigh)... Really, builders need to [censored] so that 120 years down the road things do not need to be fixed only because it was done inadequately the first time.
The thickness required for closed cell foam to become a vapor barrier varies depending on brand. No close cell spray foam becomes a vapor barrier at 1". You need to look at the TDS of the foam you are using. Most require at least 1.5", some required over 2". This system will work, it just super over kill. I have been a spray foam contractor for 15 years and studied at the Kansas Building Science Institute.
@@johndeerefarmer4483 No it is not. The technical data sheet for each spray foam will list the minimum amount of spray foam to reach a perm rating of less than one. To be considered a vapor barrier the perm rating has to be below 1 perm as defined in the building code. Perm ratings are not defined by climate zones. If you know of one please let me know.
But does that correlate perfectly with being adequate to prevent condensation? I mean just because it has a perm greater than one doesn't mean that's enough to move a homes amount of moisture through it
When they spray the stuff on the roof Rafters and underlayment of a roof, if the roof leaks how can they tell where it's coming from? Doesn't it hold the moisture against the wood and then cause more damage instead of draining?
Something I've been wondering about with sprayfoam since I started seeing it, is how much of a P.I.T.A. is it if you need to do some rewiring/renovating ? To me it seems like it would be a lot as you have to dig the wires out of the foam, and dig new channels for the wire if you are re routing it.
Do you have to remove the old wire, or just disconnect it? At least with flash and batt and t-studs you'd just need to dig out the foam through the studs.
Last year was visiting a remodel where they pulled off all the sheetrock, pulled all the two conductor wire and were going back with NM 12/3) and put in Smurf tube conduit so they could change it at some date in the future if ever necessary without ripping up the walls.
On a flat roof 18’ tall in front, back is 10’ tall framing out 4” metal studs 14 ga on top putting plywood and metal roof. Is it ok to spray foam for condensation ? 1200 sq ft home.
Would this be a smart, efficient move for a Vented attic space? Long Island, NY area. Current attic insulation is lacking & a lot of poorly installed batts. Crushed, no vapor barrier…etc….
Can you please post the link to the document you eluded to? SPFA-147 Spray Polyurethane Foam for Hybrid Insulation Systems - Part 2: Climate Zones 4-7:
If I need to pull my siding off my house, and there is currently no sheathing or vapor barrier beneath, can I use closed cell spray foam against the sheetrock before installing new sheathing, vapor barrier, and siding over it?
Can anyone touch on the batt filling the cavities completely (I’m specifically wondering about the warm side). In the vid it says batts have to touch all 6 sides. To help describe what I’m confused about: if you were to use a 2x4 sized batt in a 2x6 wall (FYI I’m not saying this) would it not perform as 2x4 batts would with 2x4 studs?? Thanks
Yes, it would not perform well. The empty space allows an internal circulating convection current, which causes a lot of heat transfer. The primary purpose of insulation is to prevent these convection currents from forming. That is why it is important to completely fill the space.
What advice would you have on dealing with full dimension 2x4 walls in zone 6? I considered using .5" of rigid foam or 1" comfort board or and firring out .5" on the inside with R-15 Rockwool. I am also considering firring out either the inside or outside walls 1.5" and going the flash & batt route or R-19 Rockwool. I am from the south but this house is in the north and I don't want to get this detail wrong... Any ideas would be much appreciated!
Matt, You and Ken are another Dynamic Duo! Question: Considering Zip-R vs your InSoFast, would calculations be any different??? 😊 I am also planning to use the 2x6 T-Stud for my new home with 2" CCSF inside here in Coastal NC. Cheers, Eric
Love his shows. Would LOVE to see his final cost as an actual house buyer not as the builder just to see the per square foot price. I can't imagine the regular home owner could ever come close to affording this type of build on a 2k sqft. home.
I hate doing flash and batt but I really hate doing it with mineral wool lol. If I am doing flash and batt i prefer to use Knauf batts (fiberglass and mineral wool blend acoustic batts)
@@rbnhd1976 if it were up to me every job would be 100% cellulose blown in. But blowing over foam would be up to the customer or builder. More time and money
HD and Lowes used to carry Roxul. No more. At least not in Maine. What's the reason for that? Anyone know? I swear it's Owens Corning that pushed them out. Because, now they carry an OC version of the roxul style insulation and it's not the quality of Roxul.
I'm doing 3" of closed cell in my attached heated / cooled garage / shop. Zone 5. I will have 2.5" of space left in the wall that I could fill with rockwool. Will it be a problem to use this in a space that I might not always want to condition? If I am going out of town for the week I plan on not conditioning the shop.
I used closed cell foam on first light layer. Then put Rockwool 3 in batts next layer and it is very cool in summer and very warm in winter. Never any problems. You will be fine no need to over do it.
Belt and suspenders type of approach. Plus I'm sure that he is getting sponsored products with nearly everything he has used. Not free, but steeply discounted I would bet.
They did this to get a house up to passive house standards on This Old House once. This was in the Northeast so Rockwoll would have not provided enough R-Value to reach passive house standards.
Total embodied carbon is 10x higher than fiberglass and the r value is 4.2 per inch. Unless you are using Rockwood for sound, it’s not worth the cost. Foam and fiberglass is good, exceeds code, and good air barrier. Fire resistance won’t matter when the entire structure is wood.
The problem with flash and batt is the majority of insulation companies only install 1/2” or less of closed cell foam. After putting installing foam below manufacturer recommendations, they cram a fiberglass batt into the cavity. The fiberglass batts are designed to completely fill the cavity for maximum effectiveness. They aren’t made to be crushed down. The methods used in this video are overkill, but installed correctly with enough cavity space for all materials.
Not if you have enough closed cell. As they said in the video, the depth required to prevent that depends on your climate, but if you meet that depth at your lowest, condensation will not (should not) be a problem. As they said here, this system is letting the closed cell do all the insulative work (already at R-17 in the wall) while the Rockwool is serving primarily as a sound insulation. Whatever insulative value it offers over the closed cell's R-17 is just bonus.
Your absolutely right, having 2 insulation with a gap between them two creates moisture that leads into mold. And mold can lead to people leaving at the house to have serious health problems. In the video, the assured that there is no gap in between. However, we’ll have to see and find out over the period of a few years. I would of honestly, done 1” of close cell and then filled it in with open cell.
How? This problem never passes the sniff test. Warm air must meet cool air to condensate. That means you either can: A) Install thick batts to stop warm air from reaching the foam B) Run visqueen over the batts at the interior (like in the north) Neither requires spraying a ton of thick expensive foam..... 😠 NO moisture can come from the outside IN, because the close cell stops it.
@@InvestmentBankr correct to an extent. The primary purpose of "visquene" (ideally 6 mil poly) is to provide a barrier for "vapor". Hence the term "vapor barrier". No vapor, no condensation. (internal sources of vapor must be dealt with in other ways)
@@nelsongilbert1695 You seem to be describing exterior vapor barriers, However, interior vapor barriers of visquene installed over paper or non faced batts is incredibly prevalent north of zone 6. In effect northern homes have stud bays COMPLETELY isolated from air flow on both sides for a perfect seal.
Interesting video, thanks, the link to SPFA appears to require a membership to access, I am particularly interested in the applied thickness recommendation for for cold climates as I live in Fairbanks Alaska
Hello Matt! Can you tell us viewers if dark exterior paint colors affect the efficiency of a home and if so, by what kind of approx margin? We are building a home and wanting to paint it navy but we are afraid the dark color will make cooling it difficult. For reference, we are in NC and we NEVER run the heat, even in the winter. If its only 5-10% power consumption increase then we may go ahead and do it. But if its something significant, it would be interesting to know. Maybe this would be a cool science video for you guys :)
These videos will spoil future home builders. I talked to several builders who had no clue what Zip r sheathing was let alone T-studs. They were reluctant to try anything new. Building my house like this would have cost me a little more in material cost but made finding a builder much more costly and complicated in itself.
,,,Mat Risner,,, I just built 2 different houses, one they had 1 to 1 1/2" of closed cell sprayed in and no bats . The other one they had 5 1/2" of open cell. So your saying that the one with closed sell needed bats , correct.
I have seen horror stories on flash and batt. Would you suggest a blower door test and aerobarrier before the bat? to triple check to make sure there is no holes/ air leaks missed during the spray foam part?
something I don't get, and i'm hoping people will either confirm or correct me here.... But wouldn't it be better to do this the opposite way? I've seen so many issues with dewpoint etc with the foam and batts. Why have the foam exterior and batts interior? Would it not be better to cover inside somehow maybe vapour barrier etc (as you dont want to drywall without exterior sheathing and housewrap) and then spray foam from outside onto the backing of interior wall, and the batt on the exterior before exterior sheathing? I know this would make build a bit more complicated etc..... just meaning in terms of overall performance of the insulation. This would still air seal, act as vapour barrier etc but be better in terms of the dewpoint? Im in a cold climate btw. Also have been thinking about this as a retro fit option to an already built house with rotting exterior ply. so interior drywall already there. remove sheathing, spray foam back of drywall, then batt and re sheathe and siding.
We vapour barrier on the inside as it a cold climate, this is my reason for thinking that way. Gives vapour barrier on the right side, air seals, and dewpoint wise this should eliminate issue. Also I was meaning to remove the poly VB after spray foaming. or use 1/4 ply interior. Or maybe drywall and spray foam right away (foams good enough to waterproof while batting and exterior sheathing)
In our cold Canadian climate best practise is to spray foam the outside of the wall, not the inside cavity. IMO best method is to build with 6 mill vapour barrier behind drywall> 2x4 or 2x6 framing> fill wall cavity with rockwool insulation> apply liquid barrier to the exterior sheathing to stop any air leakage and install R8 or R10 continuous EPS insulation. It must to be EPS. DO NOT USE pink or blue rigid foam on the exterior of a house. The downside to this method is there will be no room left for brick or stone unless your foundation is 10" thick.
love the back and forth complete (yet layman-friendly) explanation of the closed cell. wasn't quite sure why the rockwool was even needed, since you already got to an R14 in TX with the closed cell -- if 14 wasn't enough why not just another inch of spray?
Cost. Closed cell is 3x more expensive than open cell. He is going with the wool for sound conditioning. But mostly, he wants more than minimum insulation because of the climate. Building codes tell you the MINIMUM acceptable amount of material. You are free to exceed that if you want. Which he clearly does want to do.
Cover it with Aluminum double bubble across the studs and tape it off. The ceilings too, Reflects heat out reflects heat in. Cut my heating and a/c bill by 80%. You couldn't pay me to put batt insulation in my walls. You Guys complaining about the cost, I get it, but if you do that with foam and then cover it across the studs every day of every year you will be paying yourself back. By My rough calculations it took 3 years to pay off the entire insulation job. Been money in the bank ever since..
I was a insulator (Residential) in the late 80's and early 90's & when I started the standard was R7 in the walls "with plastic" R19 floor & 30 in attic, when I left & went on to a different profession it was still the same orher than we were using R15 in the walls without plastic, I'm in N.C Raleigh area. It's amazing how far the industry has come. And I have to add I've been around construction & builders my whole adult life about 40 years & you my friend are a hell of a builder, I would love to have you build me or anyone in my family a home, I could rest knowing it was done with integrity.
This house is a case study in good practice
Shut yo moruh
R32 walls in Texas. Are you kidding?
@@MrTexasDan A well insulated building in any climate will reduce your energy bills. It will also reduce the size of your heating/cooling equipment.
Except the black roof which he did just for looks
@@magictrading8903 the 4 inches of spray foam alone is R 28...
It would be nice to see insulation reviews start to show and include just how effective cork can be. Also, cork has many benefits to the environment. Is renewable, carbon sink, water resistant, vapor permeable, is almost perfect as insulation.
That foam is no joke. Used it to insulate around some old loose vinyl windows and the foam locked the windows in place better than the screws and blocking did.
No kidding was replacing a door and frame that was sealed with a foam and fastened with bolts, so I unscrewed all the bolts I could find and cut with a power saw from all around the frame and still needed two of us to push the frame with the door loose.
No joke is right! Commercial insulator came in and did kitchen, under floor and under a crawl space. Later, didn't realize I could not set the outlets back. Thankfully the tile backsplash was thick enough that it didn't affect the boxes sticking out max. Make sure that anything needed to set (outlet depth on adjustable boxes, etc) is done BEFORE spraying. Also made mistake on not adding layer of roxul before the sheetrock went up, and ceiling. But so far, temps are good but would like to noise reduction benefit. Next home...
There is no racking force applied. If you took a force and pushed sideways against the foam it would crush like you stepped on it.
icredibly well informed. Rockwool is incredible for sound and batt. I have bought from IDI...Good company. You hit the spot with just enough for each application. Too many times the builder or homeowner is not interested in foam because they think they need an r-49 cavity foam filled....7" is overkill. 3" is max. You are spot on brother. And your exterior wall design is interesting. That wind blowing hard in the background was a great sales pitch on the foam too....Awesome video. I just came across it.
Matt, your knowledge and unselfish advice is gold to many of us. Thanks for sharing this incredible information. Priceless.
OK, this answers my (and others) questions about the closed cell foam install.
Now this brings us to the next question. What is the upcost of this wall (the 2x3 (5.5" wall thickness) heat break, Zip sheathing, foam, Rockwool) vs a "code" wall (for that area) and how does it compare (costwise) to, a comparable (R-value) ICF wall. If the ICF wall is cheaper, then how much more R-value can you add for the same cost?
Love these shows! Please keep them coming!
Minnesota built home here. Cant stress enough put enough foam 2"+ and CONTROL THE MOISTURE through the entire build if its happening through the winter. I neglected to do so and had a lot of condensation occur between the flash and the batt when we had our extreme cold snap which occurs once if not twice a winter. Matt if you read this please look to mentioning it, because its still relatively new concept many aren't aware of, and it can be extremely scary situation. In my case all of it dried out as designed once it warmed up a bit and I dropped the moisture levels as much as possible.
What was the exact assembly? Poly on the interior or something like smart membrane? A flash coat in cold climate can be a risky assembly if not done right.
Controlling moisture is hardly a new concept since polyethylene sheets have been standard in northern walls for close to 50 years. What is new is the realization that even in the north, it might be hot and humid outside while the inside is cool and dry (due to air conditioning), so interior poly isn't a good idea anymore.
@@hailexiao2770 if cool and *dry*, would condensation still occur?
We just foamed our home is Minnesota. 6" closed cell (R42) under the roof decking and 4" (R28) on the walls. It's incredible stuff!
What brand did you use?
R values are a joke, R42 of foam is like having R90 of batt insulation.. I bet you can heat your house with a candle.
In South is enough open cell for walls and roof.We used to spray closed cell the sub floor /freezers. Closed cell is good for vapor barriers and R value, open cell - R value and sound . Cold states : roof - first closed cell ,then open , Sub floor - open cell first , then closed .
I own 2 houses next door to each other, almost identical in layout, one built in 1908 & other 1910, both houses I redid the 3rd floor (complete gut). 1st house is ours & put in Rockwool with polyiso board on the inside (R-6 with drywall to go over it). This reduces thermal bridging through ceiling joists. Next house did closed cell foam between ceiling joists (both houses have roof above it). Considering the performance & price I would definitely do the Rockwool/polyiso combo. Probably half the price (with my labor) & I think it performed better. Again, exact same 3rd floors, next door to each other so a pretty good comparison. Close cell spray foam was about $6k for just the 3rd floor ceiling/walls.
Yeah in retrofit/renovations, when you can put whole boards, its way cheaper for same performance.
“I’m not in a high wind zone”, as the plastic door opening is blowing at a sustained 120mph! 😂
Great meeting you at JLC the other day Matt!
Just found this channel, REALLY like it over *other* spray foam (jones) videos ! He claims you can't do this!😮😂
Your Videos are really educational I’m an air-conditioned contractor in Louisiana I love the way you explain everything you’re a great contractor, I would love for you to build my home !
That is absolutely the very best application I've ever seen
Wow! LOVE the idea of using the "zip" boards to fix the thermal bridging from the studs!
first time someone else besides Spray Jones has said how to do a proper flash and batt! good job. rule of thumb though without looking it up is over 2/3rds ratio. so R14 of closed cell means you should only do a max of R8 in batt form which of course isnt really a product anyone sells. youre better off just doing the 2-3" of closed cell and calling it a day.
you are probably right, but i'm one of those neurotic people who is gonna pay extra just to put some insulation in there JUST BECAUSE lol
@@dovahkindragonborn9827 but pay for that massive R value in closed cell then. keep on packing that R7 in there vs doing more labor and spending for only an R3.5.
Watch Spray Jones. Unless you’re doing this for noise you’ve spent a lot for very little gain….
Spray Jones is just a dumb contractor. Don't listen to anything he says. He's faking his knowledge, just like most of the clowns on UA-cam.
@@CybekCusal lol the guy in Matt’s video literally said the same thing though and he points to probably the same thing Spray Jones is referring to
we're building a custom walk in cooler for a taproom in Philadelphia. Trying to figure out the climate zone and where I need the dew point to be/or if I even need to worry about one. It's a conditioned space inside of a conditioned space. That being said, very helpful video!
hey matt I want you to talk about the final process of a build. what the contractor usually does before handing it off to the client. window cleaning! I am a window cleaner construction clean ups are a regular part of the job. id even love to clean your windows myself when the time comes.
Hi Matt, great vid as always
Just a question re the vapor barrier, if the closed cell is a VB and the ZIp system is a VB, then could this result in a vapor trap for the wood in the zip system?
Could be in cold climate!
T-Studs are kiln dried. check the moisture content on yours b4 u install. Not a problem if u have "no open in-wall cavities". If you have "open in-wall cavities" allow for in-house air to circulate.
Got a price of 125 dollars a sheet of ZIP R 3. How can someone afford to cover a whole house in it?
dont waste any of it. literally tape up all your extra pieces for a bonus sheet.
Economies of scale is where it comes in, plus not only is it sheeting but also insulation.
but your getting more than just sheathing.... house wrap / r-value not to mention what bs house wrap is
I got R9 for 65 a sheet
He got it for free...
Basically a R32 in a wall in, what, Texas? That's going to perform so well. Wish I had that in my house...
Indeed. For what looks like a 50-85F average yearly swing, R32 seems overkill.
You are only asking your HVAC for a delta of 20F. I guess he's well prepped for the next storm.
@@joshpit2003 since you bring that up, will his HVAC units perform well? like not short cycling etc and fail sooner since they dont get proper run time?
@@joshpit2003 Yes, for Austin, R32 walls are WAY overkill and stupid expensive over what you get with just 2x6 walls with pink stuff. But overkill and expensive never stopped Matt from taking it for free and advertising it for his sponsors.
@@billlan0 Hmm, solar. There's another poor use of dollars. At the electric rates in Austin, it takes 20-30 years to break even vs. on-grid power (just in time to replace the worn out system). This is true unless you take the subsidies which are paid for by your neighbors.
@@neckofthewoods24 He'll be totally fine. They're won't be any short cycling in his ac. So much ai, learning, temperature modeling it'll turn on for awhile to get to temperature and not turn back on for quite awhile. He's going to size it appropriately. If he goes too big of a unit what you're saying could happen.
I’ve seen it all, rockwool insulation, spray foam insulation, and now both
Nice assembly Matt. It's coming along nicely.
Sound will go through electrical boxes. Here in Russia Acoustic group produce sound reducing electrical boxes for drywall. Sure they are for European DIN standard.
I learn something useful on every video. Awesome video.
Thank you so much for this video. My framing (100 year old masonry block house balloon framed house) is offset by 5" from the exterior block wall for structural reasons. We're spraying 2" of ccSF on the block. Then I want to add batts. My question is do the batts need to be thick enough to fill entire gap from the foam to the drywall (as much as 6.5") or can there be a gap between the ccSF and the batt? Or can I put 3.5" rockwool batts on top of the ccSF and leave the gap between the rockwool and drywall? Help!
what is that green spray on the first 32" of the t studs"
We are purchasing a home built in the 80s in the north houston area. What are the rules when doing the attic with the closed or open cell foam? As far as AC equipment, venting, etc
What’s the point of vapor open WRB/Zip if you are spraying vapor closed close-cell foam behind it? Please someone explain.
Zip isn't vapor open.. it's very low perm.
Zip is made from OSB. Which is very prone to water damage, regardless of what manufacturers claim. Since the zip is backed with a closed cell (vapor barrier), the idea is that the vapor open (outside surface) is necessary in order to allow the OSB to dry outward in the event that water makes it past (which it will, from over-driven fasteners, constructions scratches, and poor tape-jobs).
@@joshpit2003 perm 1 is not vapor open ..
@@joshpit2003 surprisingly huber zip OSB is pretty resilient to if left outside. I have a test board Ive left outside over a year explode to rain and sun and while noticeable greying/bleaching no bulging or degradation.I suspect they are elevragign their research nd manufacturing they've had so much success with re advantech sub flooring.Now admittedly my test board is drying optimally and no exposure to standing water, but hell, most PT wood wont stand up idneficntley to standing water.
@@joshpit2003 I looked up the product data. The Zip sheathing itself without the insulation is 12-16 perm, which is very Vapor open. But the insulation is less than 1 perm. I agree with your comment that the vapor openness is to counter any water intrusion from outside potential through compromise in the factory applied water/vapor barrier by fastener holes and etc. However, this is not supposed to be used if the concern is more for vapor drive coming from the inside, such as compromised vapor retarder in a northern heating dominant climate. What Matt is doing here with vapor closed spray foam in Texas would have no issue. But you probably want to avoid this assembly in northern climate, due to the vapor closeness of the whole assembly. The best would still be exterior insulation with some batt insulation that keep the sheathing in the warm side, with vapor open assembly to allow vapor drive outwards. Correct me if I am wrong.
A bit off topic, but was is the green coating on the bottom portions of the studs ?
I am assuming it's to stop mold from forming.
I love this stuff. That is a beautiful wall assembly.
At about 8:55, Matt discusses MW printing the R-value on the batt. During the install R15 was placed on the lower section and R13 was placed in the upper section. Was that a specific design decision or a quality control issue?
mixed bags
That's probably my favorite insulation system. Yes it's a little bit more expensive but really good... and more than enough for Canada too.
What a well engineered wall system.
Matt we are in the middle of a remodel and can’t find a straight answer. Our house is 105yr old in a dry California climate. It was built with wood siding, a felt layer, and 1/2” wood sheathing. It doesn’t have a vapor barrier do I need to add one or use hard foam insulation before putting in Rockwool? What would be the best way.
Matt, what are your thoughts on doing a spray in fiberglass over the foam, such as jm spider plus or knauf jetspray?
How can this be done when redoing the siding from the outside of the house? Put bat's down and spray foam over it?
In this particular hybrid method, why the closed cell foam and not an open cell foam?
In northern climates, isn't it common to seal as a last interior later before drywall with a layer of plastic sheet (or some equivalent) to prevent condensation? Many northern assemblies don't use spray foam, but that seems to be suggested at 4:00 - 6:00. I thought in northern climates we dried to the outside, which spray foam might actually complicate in an imperfect assembly.
No plastic sheet in this assembly. The spray foam provides that. A secondary sheet of 6mil poly would create a double vapor barrier and trap moisture.
Yes D you are correct.
Up north where I am in Canada they did require a vapor barrier sheet before the drywall, and the spray foam had to be covered with fireproof insulation. This a was in a basement. I wouldn’t leave out the interior vapor barrier even with the spray foam, it gets to -40F here, you want all the condensation protection you can get.
@@EdwardT9 it's not fireproof insulation. It's called ignition barrier, for example blazelok.
Even in northern climates hot and humid summers are common, so the interior plastic sheet can make the condensation problem worse. Spray foam based assemblies don't need to dry, since no surfaces that water vapor can reach will ever be below dew point.
One thing I most definitely like about UA-cam, sort of like the books or magazines of old (of which I do not buy or have any more), is that I can refer back to them (haha... if I remember where they might be, but so to was the case with books and magazines, but at least now I have an intelligent(?) search engine). Currently I do not know what is in my house's walls, but I know there is nothing in my floors for I having a house with a crawl space and having inspected that visually. (Sigh)... Really, builders need to [censored] so that 120 years down the road things do not need to be fixed only because it was done inadequately the first time.
The thickness required for closed cell foam to become a vapor barrier varies depending on brand. No close cell spray foam becomes a vapor barrier at 1". You need to look at the TDS of the foam you are using. Most require at least 1.5", some required over 2". This system will work, it just super over kill. I have been a spray foam contractor for 15 years and studied at the Kansas Building Science Institute.
1" is thick enough for a vapor barrier in certain zones. 2" is enough in zone 6
@@johndeerefarmer4483 No it is not. The technical data sheet for each spray foam will list the minimum amount of spray foam to reach a perm rating of less than one. To be considered a vapor barrier the perm rating has to be below 1 perm as defined in the building code. Perm ratings are not defined by climate zones. If you know of one please let me know.
@@markking3531 A better statement is "you don't need a vapor barrier (
But does that correlate perfectly with being adequate to prevent condensation? I mean just because it has a perm greater than one doesn't mean that's enough to move a homes amount of moisture through it
Can you show how you would put in a fire place in a netzero home?
When they spray the stuff on the roof Rafters and underlayment of a roof, if the roof leaks how can they tell where it's coming from? Doesn't it hold the moisture against the wood and then cause more damage instead of draining?
Something I've been wondering about with sprayfoam since I started seeing it, is how much of a P.I.T.A. is it if you need to do some rewiring/renovating ?
To me it seems like it would be a lot as you have to dig the wires out of the foam, and dig new channels for the wire if you are re routing it.
Do you have to remove the old wire, or just disconnect it? At least with flash and batt and t-studs you'd just need to dig out the foam through the studs.
Last year was visiting a remodel where they pulled off all the sheetrock, pulled all the two conductor wire and were going back with NM 12/3) and put in Smurf tube conduit so they could change it at some date in the future if ever necessary without ripping up the walls.
Just put in conduit before you spray foam and you're good to go.
Can someone check my vision? At 9:00, look at the insulation label, does the lower batt say R15, and the upper batt say R13? Thanks.
Look on the left of it, it's a 5. Only looks like a 3 because the top-left little 'L' hook of the five didn't print properly.
On a flat roof 18’ tall in front, back is 10’ tall framing out 4” metal studs 14 ga on top putting plywood and metal roof. Is it ok to spray foam for condensation ? 1200 sq ft home.
What about the top of studs need to be sealed.
Would this be a smart, efficient move for a
Vented attic space? Long Island, NY area. Current attic insulation is lacking & a lot of poorly installed batts. Crushed, no vapor barrier…etc….
In the south could you fill the bays all the way and then put up foam insolation panels across the wall and then put up the drywall?
Can you please post the link to the document you eluded to? SPFA-147 Spray Polyurethane Foam for Hybrid Insulation Systems - Part 2: Climate Zones 4-7:
Nevermind. Here is the link: www.sprayfoam.org/store_product.asp?prodid=65 It cost $25........no thanks. 🤦♂️🙄
My question is how does the vapor get out of the wood?
If I need to pull my siding off my house, and there is currently no sheathing or vapor barrier beneath, can I use closed cell spray foam against the sheetrock before installing new sheathing, vapor barrier, and siding over it?
Can anyone touch on the batt filling the cavities completely (I’m specifically wondering about the warm side). In the vid it says batts have to touch all 6 sides.
To help describe what I’m confused about: if you were to use a 2x4 sized batt in a 2x6 wall (FYI I’m not saying this) would it not perform as 2x4 batts would with 2x4 studs??
Thanks
I’d look at the channel Spray Jones, and watch his videos on the subject.
Yes, it would not perform well. The empty space allows an internal circulating convection current, which causes a lot of heat transfer. The primary purpose of insulation is to prevent these convection currents from forming. That is why it is important to completely fill the space.
Yes it would, since the extra exposed surfaces of the 2x6 would act as cooling/heating fins.
Wouldn't the spray foam act as a vapour barrier being placed facing the outside?
What advice would you have on dealing with full dimension 2x4 walls in zone 6? I considered using .5" of rigid foam or 1" comfort board or and firring out .5" on the inside with R-15 Rockwool. I am also considering firring out either the inside or outside walls 1.5" and going the flash & batt route or R-19 Rockwool. I am from the south but this house is in the north and I don't want to get this detail wrong... Any ideas would be much appreciated!
Matt,
You and Ken are another Dynamic Duo!
Question:
Considering Zip-R vs your InSoFast, would calculations be any different??? 😊
I am also planning to use the 2x6 T-Stud for my new home with 2" CCSF inside here in Coastal NC.
Cheers, Eric
Love his shows. Would LOVE to see his final cost as an actual house buyer not as the builder just to see the per square foot price. I can't imagine the regular home owner could ever come close to affording this type of build on a 2k sqft. home.
If estimate This house with all it's high end upgrades, energy features in the $400/sf range
I hate doing flash and batt but I really hate doing it with mineral wool lol. If I am doing flash and batt i prefer to use Knauf batts (fiberglass and mineral wool blend acoustic batts)
Why not blown in, of some sort. After flash I mean
@@rbnhd1976 if it were up to me every job would be 100% cellulose blown in. But blowing over foam would be up to the customer or builder. More time and money
We need min r40 walls in Canada...r60 roof. Spray spray spray
Can this also be done to attic floor? Thanks
HD and Lowes used to carry Roxul. No more. At least not in Maine. What's the reason for that? Anyone know? I swear it's Owens Corning that pushed them out. Because, now they carry an OC version of the roxul style insulation and it's not the quality of Roxul.
I'm doing 3" of closed cell in my attached heated / cooled garage / shop. Zone 5. I will have 2.5" of space left in the wall that I could fill with rockwool. Will it be a problem to use this in a space that I might not always want to condition? If I am going out of town for the week I plan on not conditioning the shop.
I used closed cell foam on first light layer. Then put Rockwool 3 in batts next layer and it is very cool in summer and very warm in winter. Never any problems. You will be fine no need to over do it.
Isn't the vapor barrier on the outside?. Tyvek or zip coating?
Are t studs cheaper than a 2 x 6 in today prices?
but the zip-r takes care of thermal bridging...so why have the t-studs?
Belt and suspenders type of approach. Plus I'm sure that he is getting sponsored products with nearly everything he has used. Not free, but steeply discounted I would bet.
SPFA docs are not available for free. Shame. Still a very good video.
Does the spray insulation “gas-off”?
What about putting open cell foam on top of the closed cell foam?
They did this to get a house up to passive house standards on This Old House once. This was in the Northeast so Rockwoll would have not provided enough R-Value to reach passive house standards.
Total embodied carbon is 10x higher than fiberglass and the r value is 4.2 per inch. Unless you are using Rockwood for sound, it’s not worth the cost. Foam and fiberglass is good, exceeds code, and good air barrier. Fire resistance won’t matter when the entire structure is wood.
Where is the warm in winter side vapor barrier?
Rockwool raised the price of the R15 bag $21 overnight in February 2024 to increase profits. So eff them!
The problem with flash and batt is the majority of insulation companies only install 1/2” or less of closed cell foam. After putting installing foam below manufacturer recommendations, they cram a fiberglass batt into the cavity. The fiberglass batts are designed to completely fill the cavity for maximum effectiveness. They aren’t made to be crushed down. The methods used in this video are overkill, but installed correctly with enough cavity space for all materials.
If there’s a gap between the foam and Rockwool it’ll condensate and cause horrible problems right?
Not if you have enough closed cell. As they said in the video, the depth required to prevent that depends on your climate, but if you meet that depth at your lowest, condensation will not (should not) be a problem.
As they said here, this system is letting the closed cell do all the insulative work (already at R-17 in the wall) while the Rockwool is serving primarily as a sound insulation. Whatever insulative value it offers over the closed cell's R-17 is just bonus.
Your absolutely right, having 2 insulation with a gap between them two creates moisture that leads into mold. And mold can lead to people leaving at the house to have serious health problems.
In the video, the assured that there is no gap in between. However, we’ll have to see and find out over the period of a few years.
I would of honestly, done 1” of close cell and then filled it in with open cell.
How? This problem never passes the sniff test. Warm air must meet cool air to condensate.
That means you either can:
A) Install thick batts to stop warm air from reaching the foam
B) Run visqueen over the batts at the interior (like in the north)
Neither requires spraying a ton of thick expensive foam..... 😠
NO moisture can come from the outside IN, because the close cell stops it.
@@InvestmentBankr correct to an extent. The primary purpose of "visquene" (ideally 6 mil poly) is to provide a barrier for "vapor". Hence the term "vapor barrier". No vapor, no condensation. (internal sources of vapor must be dealt with in other ways)
@@nelsongilbert1695 You seem to be describing exterior vapor barriers, However, interior vapor barriers of visquene installed over paper or non faced batts is incredibly prevalent north of zone 6. In effect northern homes have stud bays COMPLETELY isolated from air flow on both sides for a perfect seal.
is it a problem that your roof does not breathe?
Why not just cap it with open cell foam instead of rockwool? Is it purely the cost ?
Interested in your personal studio wall assembly. What fabric did you use?
Interesting video, thanks, the link to SPFA appears to require a membership to access, I am particularly interested in the applied thickness recommendation for for cold climates as I live in Fairbanks Alaska
I would like to do this process on a barndominium
Can you flash & bat these products in a roof insulation job?..would be phenomenal.
Hello Matt! Can you tell us viewers if dark exterior paint colors affect the efficiency of a home and if so, by what kind of approx margin? We are building a home and wanting to paint it navy but we are afraid the dark color will make cooling it difficult. For reference, we are in NC and we NEVER run the heat, even in the winter. If its only 5-10% power consumption increase then we may go ahead and do it. But if its something significant, it would be interesting to know. Maybe this would be a cool science video for you guys :)
incredible didactic and important!! many thanks!!!
Won't the closed cell foam shrink over time??
These videos will spoil future home builders. I talked to several builders who had no clue what Zip r sheathing was let alone T-studs. They were reluctant to try anything new. Building my house like this would have cost me a little more in material cost but made finding a builder much more costly and complicated in itself.
,,,Mat Risner,,, I just built 2 different houses, one they had 1 to 1 1/2" of closed cell sprayed in and no bats . The other one they had 5 1/2" of open cell. So your saying that the one with closed sell needed bats , correct.
I have seen horror stories on flash and batt. Would you suggest a blower door test and aerobarrier before the bat? to triple check to make sure there is no holes/ air leaks missed during the spray foam part?
@Bob Watters condensation on the bat causing mold and people having to rip and replace
@Bob Watters if there is any air coming thru the foam your screwed.. ie bad foam job
Bob go to about 8min mark..
ua-cam.com/video/yrFIfg8A3i4/v-deo.html
If that is not the video.. this build had the problem.. they might have taken it down
Great show.
Can you flash and batt the attic? Cuz that’s where the sapping heat comes from. 🔥
something I don't get, and i'm hoping people will either confirm or correct me here.... But wouldn't it be better to do this the opposite way? I've seen so many issues with dewpoint etc with the foam and batts.
Why have the foam exterior and batts interior? Would it not be better to cover inside somehow maybe vapour barrier etc (as you dont want to drywall without exterior sheathing and housewrap) and then spray foam from outside onto the backing of interior wall, and the batt on the exterior before exterior sheathing?
I know this would make build a bit more complicated etc..... just meaning in terms of overall performance of the insulation. This would still air seal, act as vapour barrier etc but be better in terms of the dewpoint?
Im in a cold climate btw. Also have been thinking about this as a retro fit option to an already built house with rotting exterior ply. so interior drywall already there. remove sheathing, spray foam back of drywall, then batt and re sheathe and siding.
We vapour barrier on the inside as it a cold climate, this is my reason for thinking that way. Gives vapour barrier on the right side, air seals, and dewpoint wise this should eliminate issue.
Also I was meaning to remove the poly VB after spray foaming. or use 1/4 ply interior. Or maybe drywall and spray foam right away (foams good enough to waterproof while batting and exterior sheathing)
In our cold Canadian climate best practise is to spray foam the outside of the wall, not the inside cavity.
IMO best method is to build with 6 mill vapour barrier behind drywall> 2x4 or 2x6 framing> fill wall cavity with rockwool insulation> apply liquid barrier to the exterior sheathing to stop any air leakage and install R8 or R10 continuous EPS insulation. It must to be EPS. DO NOT USE pink or blue rigid foam on the exterior of a house. The downside to this method is there will be no room left for brick or stone unless your foundation is 10" thick.
Why don’t you use spray in rock wool?
love the back and forth complete (yet layman-friendly) explanation of the closed cell. wasn't quite sure why the rockwool was even needed, since you already got to an R14 in TX with the closed cell -- if 14 wasn't enough why not just another inch of spray?
Cost. Closed cell is 3x more expensive than open cell. He is going with the wool for sound conditioning. But mostly, he wants more than minimum insulation because of the climate. Building codes tell you the MINIMUM acceptable amount of material. You are free to exceed that if you want. Which he clearly does want to do.
It's not just cost. Closed cell foam is not a good sound barrier. It transmits sound through it pretty easily. The Rockwool IS a good sound barrier.
@@AndirHon ah, ok. thx
You should not install drywall, but instead install plexiglass.
Preferably ballistic plexi.
Mainstream construction so good it deserves a earthship style truth window🤣
Closed cell still has a thermal bridge in every stud ,header,top and bottom plate unless you wrap with closed cell 1/2” jip on the outside of OSB .
Can you recommend a good builder for middle Georgia?
Where do I find the studs used in this video?
If around r30 you have demishing returns on insulation why would you insulate higher?
Cover it with Aluminum double bubble across the studs and tape it off. The ceilings too, Reflects heat out reflects heat in. Cut my heating and a/c bill by 80%. You couldn't pay me to put batt insulation in my walls. You Guys complaining about the cost, I get it, but if you do that with foam and then cover it across the studs every day of every year you will be paying yourself back. By My rough calculations it took 3 years to pay off the entire insulation job. Been money in the bank ever since..
Any concern about moisture?
@@hdhhbsbbauudb Nope never had a problem this was in southern NJ> Stopped the termites dead in their tracks.
@@thatamerican3187 cool, ty for responding!
Where do the soffets go if you spray foamed where the rafters meet the wall?
This house was built with no soffit watch earlier videos. Conditioned attic space
use "soffit blockers" (cardboard baffles-any builders supply") in conjunction with +rafter-mates" and continuous ridge vent where require.
good luck to anybody doing remodel down the road
@matt did you consider using the pre-insulated T-studs we've seen in your other videos?