Using Rubber To Waterproof a Flat Roof | This Old House
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- Опубліковано 14 лип 2024
- Tommy explains how to seal a flat roof. Then he and Kevin install a rubber-protected roof over an addition.
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Using Rubber To Waterproof a Flat Roof | This Old House
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Very interesting, thanks for the full video
Although the basic installation is correct and fine for that area of the country. Tom mentioned wind uplift. The perimeter edge is the most vulnerable to wind damage. As an experienced roofer here on the coast of Wilmington NC I’ve seen roof damage from the results of multiple hurricanes. The biggest cause of low slope failures is because the perimeter edge failed. Drip edge should always be installed as tight to the facia as possible, as long as the face is less than 4” wide. Cleated if wider. We utilize a continuous metal cleat ,the same profile as the drip edge and one gauge heavier, of the same type of metal or as we do, stainless steel for all cleats. It’s attached through the the face of the cleat just above the kick out with either screws or stainless steel, ring shank roofing nails, 6” on center. The drip is then hooked to the cleat at the bottom by an open hem. Then the drip edge is nailed on the roof side 3” on center in a staggered pattern. The roof may fail from other causes but the perimeter edge will not. Another thing I strongly disagree w with is the soft substrate. The high density Poly-iso is s designed cover board for the purposes of sphere ing membrane . Its about 80 psi in compressibility, regular ISO 20 psi. The harder the substrate the less damage from debris. EPDM is easily penetrated by falling debris. The softer the substrate the larger the penetration through the membrane. Harder substrates prevent bigger penetration and less damage. A gypsum board made for roofing applications such as DensDeck or SecuRock is the best protection from flying debris. Both these material also have the highest wind uplift resistance for any substrate if secured properly to the roof deck. For instance , 1/2’SecuRock over a 1/2” plywood deck with 18 plates and screw in each 4’x8’ board and fully and self adhered TPO membrane has a wind uplift resistance of -135 PSF from information gather from testing by our manufacturer. Ive been a fn since the show went on the air, I have the greatest respect for Tom. TOH is far and above any other in knowledge and professional building techniques. Roofing is my profession. Need another host? Seriously check into modern low slope roof design. It ain’t the hot asphalt I started in 40+ years ago. There’s some remarkable products and installation practices out there.
Back in the 80's I learned how to do torch down roofing. On my first full roof, I was using the torch for almost 8 hours with a half hour lunch. That night I dreamed for what felt like another 8 hours that I was on that same job. I woke up feeling like I had just finished a 16 hour shift, torching down a roof. I went back to carpentry after that.
Sam V it happens on almost any job, I am an electrician myself and when I do 750 wire runs I dream about them
Haha....hilarious.
Sam
I know the feeling.
It can happen when starting a new job of any kind that your concerned of and trying to get perfect.
.... I love my carpentery and painting jobs. Just me. No arguments. Just alone with my thoughts and doing a good job.
But at 56, I’m starting to see that I have to bring every. conceivable. tool. to do a job.
And I’m putting things on hand carts now.
Forgetting
That 5/32 tapcon bit. The 3 to 2 reducer plug. Extra 1/8” bits because all mine snapped. Need the level or the grinder. The spud wrench. Forgot the rubber gloves or the safety glasses. All things that will hold up the job.
In roofing or painting you need less/ Less expensive tools.
I have been using torch on (Torch down in your Country) for 26 years. Nothing to touch it for longevity and looks.
FANTASTIC!!!
Awesome
Great video
Finally something im better at than Tom!
What is the best way to waterproof hollowcore slab roof top terrace.. i wanted final covering to be natural stone..so what should go on top of slab and how to lay tiles at the end?
Any recommendations for a good roofer company in/near Hayward CA for residential house single story, low pitch. I have shingles installed before I bought house. Thank you for video
In CA 3"1/2 and above is a pitch roof.
Contact adhesive? How do you get any air bubbles out?
Do this big washers not cause problems?
One critical question stands out in my mind. UV rays and nature (wind, water, heat, cold) would seem likely to degrade rubber rather quickly. I just want to confirm that there is no additional material on top of the rubber? If not, it would seem that the rubber will lack durability.
That's it! Just rubber with all of your consurns being true it's a cheaper roof system. Buy cheap get cheap!
These EPDM roofs depending on their thickness(45,60 or 90 mil), can last 30-50 plus years. You could add ballast(round pebbles) to increase the longevity. Those pebbles act like granules on a shingle....EPDM is used in MANY applications like pond liners, etc. So its history with water is well known.
so you extend the metal drip edge slightly out, to protect the fascia? wouldn't capillary action draw water up and under the drip edge then? or is the 45 degree angle enough to drive water off
The angle kicks it out. Pulling the drip edge slightly out is just a good insurance policy.
Bumping it out stops any possibility of capillary action. It is the point of doing it.
Can this be done on a mobile home in South-Central NY State? I've been using Silver Seal and it just doesn't work as well as I'd like.
EPDM or this type of material is often used on mobile homes.
What kind of adhesive is that?
how do you install and waterproof a skylight on an existing torch down flat roof
We have a sunroom that is extremely loud when it rains heavily. This looks like it would really deaden the sound. Is there anyone in St. Louis that you would recommend to install this?
Tony. This is something you can absolutely do yourself.
Yes...yourself. Good project.
"3 inches up over 12 inches, or 7 inches up over 24 inches"
Now I'm not a mathologist, but...
Listen again, he said 3 1/2 in the beginning.
3:12 pitch is not flat! It's low-slope. Anything more than 2:12 CAN be shingled with the correct ice/water barrier. 4:12 is generally the break point where barriers are not required with shingles
That's what I was wondering. Is there some sort of benefit to doing this rubber membrane as opposed to shingles or metal?
My garage roof have a slope of 2 degrees.
Tommy I hope you reply. live in apt and roof keep leaking into apt, first it was closet in foyer, black mold,..owners to re did the closet knock down all sheet rock to repair. then the water started leaking into kitchen every rain storm. biggest hole that was cut was 2' by 3 inches to repair. this has been over 6 times in the kitchen. then it happened in the living room I watched the cracks in ceiling open up during a rain storm had about 20 plastic shoe boxes catching the rain.. owners dropped the ceiling.
now its happening in the bedroom as I type, this. its the other end of the apt. Im worried ceiling is going to fall. I know you out here will say move...Its not that easy for me right now. they pay HPD inspectors to NOT violate them. An Inspector himself saw the cracks said its ok its wear and tear of building, just 2 weeks ago. but he was wrong. they same people they pay to keep quiet NYC inspectors are the same guys who come back to say it was properly repaired. Its leaking into hallway of building too. they keep layering the roof with more and more rolls of membrane. roof looks bowed as if too heavy. I don't think it is suppose to look that way inside apt.please everyone be kind in your replies.
What's the life span of that rubber? What happens when it breaks down and you need to replace it? Do you just cover with another layer?
35 to 40 years with routine maintenance.
If iso and substrate properly maintained then yes you could relief cut existing membrane and ReSkin for new roof.
It is recommended to remove old membrane, reuse any iso in good condition Install new membrane and metal flashing
@Anita Hiltz Definitely if you dig the shovel into the rubber. This house was likely designed so that the roof has the strength to support a large depth of snow on it.
Recommend flashing in the gap between the foam and the furring strips because if the rubber does so happen to suffer a tear, the water will be able to run off.
Why put the wood around the perimeter of the iso-board? Wouldn't that suffer from the same "too hard" problem the iso-board is intended to solve? So your rubber sheet would just be inclined to get punctured where it sits over the wood?
That's exactly what I thought- what if a branch hits the edge where the plywood is?
The metal edge covers the wood and rubber that protects both from any tree branches
Compared to shingles that roof looks like it could easily be damaged by falling branches.
That's what a substrate is supposed to be for
you have to prime the strip in
Anyone know what the cost for this is versus other flat roof membranes that can be used? What’s the life span, durability, efficiency?
Depends on the level of detail and thickness of the EPDM.
A tpo roof would be better than an epdm but more pricy better bang for your buck tho
The best and cheapest flat roof system is a 3 layer torch on Polyester SBS system.
@@danieljimenez7111 As long as it is a warm roof.
Look at Tommy still has them man hands, dry skin and all. Thanks, Uncle Tommy for all the lessons!
3.5 inches over 12 is "flat" ... wow, my roof (and most roofs around here) are most certainly flatter than that. A 50' front to back house would be over 14 feet taller on one side if that was the case.
I'm here to figure out what to do with my roof. It's 50' long and probably has a 12" rise... that's what a flat roof really looks like!
your math....3.5/144" is 2% (actually 2.4%). They are not saying 3.5" over 12".
@@racheat 0:15 he literally said 12inch, and 24inch goes up 7.
The guy misspoke. He meant to say 12 feet, not 12 inches.
How come you don't use a latex glue ,I've put on quite a few,also there is a nother roof material it's called TPO much much tougher ,by the way retired RV mechanic 44 years ✌
TPO is more rigid and reinforced providing higher puncture resistance. Shorter service life though and doesn't qualify for refurbishment. 20 year life span, set your clock to it. Even shorter pending brand and heat or reflection exposure.
TPO also not flat roof type of choice for contractors who do not normally install flat roofs due to specialized equipment required to weld seams and higher skill set using welder.
@@camllmotoll1409 everything we use on a roof in the recreational vehicle world has a flaw , Everything! Finally retired after 44 years in the business ✌and the TPO I personally have on a seller door ,it's been there now since 1999 and through a big dog Akita three children,and now two grandchildren,it is just this year showing wear on the edges ,direct sun , bicycles, skate boards ,✌✌
@@johnneedy3164 I hear you John. No doubting your claim I'm sure it will be there for many more years to come. However vertical , static applications are not the same as horizontal substrates in a roof assembly subjected to thermal expansion and contraction.
@@camllmotoll1409 I used EPDM on a roof of a rental of mine back in 1995. I put 3x3 metal on all sides. I left the original gravel ballast on the roof. Even with that, I had leak this year because the EPDM had shrunk 4" on the top of the slope (3.5" over 24')! I have been using TPO for a number of years now and it is awesome. The only expensive equipment was a $350 heat welder on Ebay. My roofing supply store says it should last for 20 years but much longer on my rentals as I, again, am leaving the ballast in place. I have used it under decks as well as it is tough and gets no UV exposure and no mechanical abuse either.
I have flutter (same type of roof) Does this mean they did not glue it down ???
Three ways to install a single ply roof. Screw it, glue it or weigh it down.
They may have Mechanically attached yours. Which will allow membrane flutter or slapping. Alot of wind noise. That is typically least expensive application. Similar service life though.
@@camllmotoll1409 Yes worried about the life ! I am concerned that it will eventually tear off due to getting old and crispy in high winds. I live at the beach where it gets up to 70 mph
Have your local Firestone or Carlisle authorized contractor inspect it. Pending the contractor they may charge fee $350
Peace.. Salam... Shalom.. Namaste...Thank You so much for All that you are doing to Heal our Mother Earth 🙏🏻 😊 🌈 ✌ 🌷 ❤
EPDM fine over plywood.
Is the rubber also known as the TPO?
no...that is a different product
3/12 pitch aint flat. Come to Florida where 2/12 is common
U forget put base sheet mr
IF AN UNVENTED ATTIC ASSEMBLY IS DESIRED IN ADDTITION TO COVERING THE ENTIRE ZIP SYSTEM SHEATHING WITH AN ICE AND WATER MEMBRANE, HUBER ENGINEERED WOODS HIGHLY RECOMMENDEDS CONSULTING A BUILDING SCIENCE OR INSULATION SPECIALIST PRIOR TO INSTALLATION. - from their documentation.
I'd paint it with the most reflective paint on the market. Black roofs are a no-no.
A 26-ga or 24-ga metal roof would be much better.
Pricy
Do you have to get exact dimensions to cover the roof with a single piece? How do you deal with side by side seams?
They overlap the joints and then use the uncured rubber strip to seal the edges.
Seam tape
@@MrJramirexWRONG
What about a flat concrete garage roof that is also used as a patio/porch? In other words there is foot traffic on it. There is one drain in the middle but not a good slope anywhere.
Pat L building regulations call for a minimum of 5" (150mm) insulation. The inspector would not pass this roof.
the video did not show the underside/interior....you aren't suggesting 5" of insulation on the top of the sheathing are you?
Do you suggest a rubber roof liquid coating? EPDM?
I've never specified rubber liquid roofing for projects, I usually specify 3 coat mastic sealant on my London jobs. This is due to the companies experience in using it but I personally would go with GRP Fibreglass. *If it's good enough for boats, why not roofs.* It's that easy any person that's fit and able can do it. ua-cam.com/video/xT9YsGBU0Fk/v-deo.html and that would cut the cost dramatically. Some companies can offer a 25-year warranty. www.fibreglassireland.ie/ or as an alternative Sika Trocal gbr.sika-trocal.sika.com/en/downloads-and-resources/application-support/guarantees.html
Look into Sika RoofPro. It's the old liquid plastics and bonds tenaciously to most all substrates.
@@heytrefre I have been looking at superior rv for rubber roof coating. 100% water seal for 15 years.
You should use cured cover strip on the metal. Uncured will not hold up to the life of the epdm
Not suggested where it rains-ask me how I know
How long before that rubber is destroyed by the sun?
Epdm .060 mil. With a good installation last around 30 years
cover with a layer of sand stuck down, and it could probably last forever.
Sun, squirrels, strong wind, hail and wrong installation too many thing can go wrong in less than a month to make it worth the effort
@@kkp4297 how would you adhere sand ? i'm sure i could figure something out, but good idea
@@frank_texas7400 Sun will take 30+ years to cause an issue with rubber, squirrels can damage any roof type, strong wind no problem if installed per industry standards or ANSI SPRI ES1 standards, Rubber is impervious to hail damage, wrong installation if done by TOH or other incompetent contractor
Use 60 Mil EPDM and you don't have to piss away your money on labor and material to prevent "falling limbs" ??
Sorry Tommy, you got 50% of the info you presented correct.
This Old House has always been week on flat Roofing. Good enough for residential contractors I guess.
Care to explain?
Sure, just a couple I noticed are 1) his screw pattern was wrong 2) they are called "plates" not washers 3) the edge metal should be stripped in with cured not uncured. 2 of the 3 I mentioned would cause you to fail any manufacturer inspection.
Torch would be much better 👌
Yeah but the days of torching are almost over. You can barely get insurance for a torch crew anymore, and they all want 2+ hour fire watch. It's going to be phased out and more and more cold process stuff is going to be the norm.
Days of open flame are long gone. Ever heard of cold adhesive or Liester gun? Stopped using open flame 10 years ago.
I'm a TOH fan, but I have never been a fan of flat roofs, period.
I love them! But the white TPX is better and stronger! Harder to handle but you can give a longer guarantee!
I seen them spraying a Rhino liner roof with an old concrete pumping truck one piece one shot one time it was amazing
Yeah i agree my old hause had a flat roof that small bastard roof made me sell my house had to fixe it twice in less than 6 years so we decided to get rid of that house !!
tyvek05 🤣🤣🤣🤣 yeah right !! The old lady’s mom had to replaced twice en last 18 years
@@michaelbearse4733 negative ghost rider. 100% inaccurate information right there
And how come your not using the white TPX on a residential? Did the owner not want to pay the extra money?
vinyl better
How come you don’t attach the flashing over a 1x2 or a 2x2
Yeah I use a 1x2 drip edge and flash over it
If your reffing to lumber size. The goal is to match the height of insulation depth and must extend a minimum 1/4" beyond metal flange
It really seems America is years behind Europe with flat roof Epdm roof covering technology. The edging strips used now are two
piece and provide a drip edge directly into the gutter and are not nailed do the nails never pass through the epdm. The adhesive
used is also not a contact one so the rubber can be brushed flat to remove air pockets. Contact glues are generally used on the 50-80 mm
edge overlay.
Could have installed a metal roof.
.
not a good idea in places like northeast....damming, water backup, ....my sister's brand new metal roof on her cape has just that, but EPDM on the shallow sloped shed dormer over the bedrooms
@@racheat yes a rubber roof is better in problem areas and especially where it snow a lot.
I live in Boston .
My son is on the Cape
He has a copper snow belt around his cape style house .
Im a flat roofing specialist and his information is wrong
Andre D how would you do it?
Can you pls educate us? I’m looking to do what they call a warm roof with 4” of insulation and moisture barrier
@@macrapidito1 first of all don't use epdm as your roof membrane you will only have problems. and the reason a cover board of iso is used is not for impact resistance its so that when the nails start backing out they wont push through the epdm
@@macrapidito1 also you are better using modbit tpo or kemper vs epdm
Andre D is TPO for diyers?
@@macrapidito1 not really but neither is any kind of flat roof chances are you are going to f it up
Roofing just sucks
bought an old house with 3 low roofs with parapets. Its destroying my life. Considering taking down the parapets and going with this system
What challenges are you facing with parapet walls? I am asking because I have a flat roof with parapet wall on my architect drawings.
I need your help please let me know how I can contact you because you can only understand it better via images. Quick brief is we have a tree going through our glass roof and we need to waterproof the opening of the tree keeping movement of tree in mind via wind pressure
technically there is no flat roofs cause you need at least a few degrees for the water not to get stuck in there
There is such a thing as a flat roof, coal tar pitch roofs were popular in the 70s because they are self healing, but for them to last they have to be dead flat.
@@jessemurphy8871 nope, they are sloped too
Coal tar pitch roofs are self healing because coal tar pitch is basically a very slow moving liquid. On hot days it will flow in to and fill any cuts or cracks in the membrane. They literally have to be flat because otherwise the pitch will flow down the drain over the course of a decade. I personally have torn off 3 dead flat roofs this year alone. Ideally, you want a 2° slope for positive drainage, but in the real world a lot of old buildings have dead flat roofs and the owners dont want to put out the extra money to add a slope package when they're already paying quite a bit of money to have their building re roofed.
@@jessemurphy8871 Yea, I have installed them. They are on a 1/8" -12" slope
@@slapppp815 maybe the ones you have done. I've been on plenty of roofs that literally have no slope. Maybe where you are it is that way, but there's a whole world out there and I doubt you've seen every roof out there.
For years I've been so disappointed in TOH team for laziness in regards to what is shown on flat Roofing.
From my perspective of a commercial Roofing contractor when watching TOH tv it appears they demonstrate proper building means and methods. I am a total idoit to residential building materials, methods or carpentry. So I've assumed what they are showing is top notch, cutting edge pushing the limits of technology.
But then when I watch flat Roofing segments I am so embarrassed for TOH. If they had just asked a local flat roofer or read some free literature on NRCA web site simply following Industry standards.
Make me wonder about everything else they show. Maybe what their showing is not as good as I thought or the best way.
Yes, they need a roofing expert just like the other trades.
What exactly was wrong with this demonstration?
@@jamesmcnaughton5092
Where to begin. ?
I guess the first thing to point out is, this is what you would typically see a professional roofer do as a 'side-job" assembly weekend cash only "paid under the table, we used to call it". So many corners were cut it's not even funny.
Until watching this, I was under the impression everything TOH would show, was considered cutting edge for construction. This reflects horribly on commercial flat roofing industry.
Let's start calling out specifically what caught my ear first.
What manufacture is it. What does the manufacture call for in this assembly? Is there a warranty? Why not? What is the geographic location of the building in relation to a high wind zone? What is the substrate? How thick is it? Is it ventilated? Why? or Why not? How is it ventilated?
Why did you choose EPDM? What mil thickness is it? Is it reinforced? Why or why not? Why was it chosen for this application? None of these things were discussed. if you watching any other trade talk about what they are doing, you have to go through all the back ground and back up why you selected this product and why it is being installed in this manner.
1- surface too hard, it could allow membrane to easily cut. WRONG - the more dense a surface under single ply membrane the higher the puncture resistance. Fact!
2- ISO is good, still considered top of the line. Thinner the insulation for a fully adhered assembly the higher the frequency on the fastening pattern. Why?
3- screw length? You used a Carlisle brand EPDM. did you use Carlisle screws? Where they the proper length for wood deck? Where they the proper screw for wood deck?
4-ANSI-SPRI metal edge? Why or why not? What is ES1 rated metal? Cleat? 24ga Kynar?
5-OSHA fall protection non existent. People were wearing a harness, but no tie off!! Safety has such a huge impact on how a flat roof is assembled, it cannot be ignored so easily.
It was such a short and thin segment, why would you even show it?
Boo Boo nobody did their homework or researched the trade. either delete the video or make another with proper information.
Any trade can be controversial, but you guys did not even try on this one.
Thumbs down! horrible.
@@camllmotoll1409 ok, but can you be specific?
@@jamesmcnaughton5092 your profile shows new account, apparently to write a comment, silly me, i thought you were being genuine with your inquiry.
Wrong fastening pattern, wrong drip edge flashing, poor decision on edge flashing detail, where was the Russ strip, no explanation or even talked to warranty
Flat roofs are ugly and are always a pain in the long term.
my thoughts too
You don't know what you are talking about but you are welcome to your opinion.
nail penatraite rubber
Crap materials. Sad.
Donald Trump. SAD!