foam strip glued to edge of studs
Can anyone identify and comment on the green strip of foam shown in this photo? The photo shows some rolls of a green strip product lying at the carpenter’s feet. Nearby, the product is shown installed running atop the floor joists. My guess is that it is some sort of foam. Like a sill sealer except just 1 1/2″ wide, made to staple to 2x studs. I’m guessing that in this photo, the strip is being installed as a sound break between the subfloor and the floor joists. I was wondering if this product would be useful to staple to the exterior surface of my wall studs instead of investing in full-coverage rigid foam boards. I’m just looking to break the thermal bridging between the exterior sheathing and the wall studs. Before I saw this photo, I was imagining getting some 1/2″ polyiso board and cutting it into 1 1/2″ strips and attaching them to the studs. Time not a problem, cuz I’m an owner-builder and will not be paying someone else to do this tedious task. I’m in a hot/dry climate zone (California, in the hot central valley), so I don’t need any external insulation. I do have to sheath the entire house in plywood because the house will be fully covered with Hardieshingle. Anyway, bottom line is I’m looking for a foam tape like in the photo to use as an exterior thermal break. Thanks to all who respond.
Edited 5/27/2005 5:50 pm ET by BarbaraD
Replies
Here's kinda a dumb question.....I comprehend you don't need insulation to keep cold exterior weather out of your house as you live in California. But....what about insulation to keep cold air conditioned air from escaping to the warm outdoors?
<<<here's my edit>>>If you're desire is to use it as thermal bridging....what is the purpose for using a thermal bridge if you aren't insulating? <<<end edit>>>
Can anyone explain it to me?
Edited 5/27/2005 8:22 pm ET by Jen
You misunderstood Jen. I live in California, but even though it's a hot/dry climate zone (per Lstiburek's builders guide books), it's cold in the winter and we use the furnace from November through early May usually. So in my exterior walls I will definitely have insulation. My choice was going to be an R-21 batt, but recently I found a source for spray polyurethane foam for 83 cents a board foot, and that was low enough to hook me. So I'll spray in just one inch of the spf, then lay in the batt. In my post I was trying to get rid of the thermal bridging at the outer edges of the studs. Maybe I'm overthinking it since it doesn't get terribly cold here. Seems our gloomiest winter days are in the upper 30's, with occasional dips down to 29 degrees.
Edited 6/11/2005 5:59 pm ET by BarbaraD
"The coldest winter I ever spent was a summer in San Francisco"
Mark Twain
NotaClue
If you decide to do that to break the thermal bridge in a wall, I'd reccommend that you use lateral bracing to stiffen the wall (the wood or metal diagonal bracing through/along the studs).
I think that area of "give' between the sheathing and the studs will effect the shear strength of the wall system (important in CA, right?). No empirical data to back this up, just a guess.
Was thinking the same thing.
Then again, the house we just built has a gas fireplace on the non-enclosed back porch....only rich people heat the out-side.
except isn't the purpose of the outdoor gas fireplace more about creating ambiance than heating?
I guess, but I've never been rich enough to afford 'ambiance'.:-)
That's greenglu. Just roll it on and stick your plywood down. NO NAILS NEEDED!
Is that like the blue glue that was used to stick down laminate in the early 90's? Lot's of cabinet guys kept in biz in FL re-doing BlueGlue jobs. . . .
Is blue glue that laminate adhesive that went on blue then changed to clear when it was ready?
What an improvement from the century old duck tape.
Seriously, what is it and what is the purpose?
I'm not sure, but I think it is foam tape for reducing floor squeeks.
Don't think so. Floor squeaks are from the floor rubbing against the fasteners. If anything a gasket like that will probably promote floor squeaks.
Sound deadening? I don't buy that either, the fasteners act as transmitters.
That is what the maker claims. Its closed cell foam with glue, and a layer of mylar on top.
http://www.integritygasket.com/
Sounds like double stick tape by a different name to me.
Jim
I was thinking the same thing. It reminded me of the butyle tape we used to use in some metal roofing applications. I couldn't fgathom how anyone would want a faom under a subfloor, but since adhesive is necessary there, a glue on a roll made sense.
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It's called "integrity gasket"
"Before I saw this photo, I was imagining getting some 1/2" polyiso board and cutting it into 1 1/2" strips and attaching them to the studs."
I think that would impact the structural bracing provided by the sheathing in a negative way.
Better to apply a contiguous layer on the outside or even the inside to create thermal break.
As for the thin foam, I'm not sure it would do much for your cause.
You're the third person to say that. So, how about if instead of 1/2" polyiso, I used 1/4" rigid foam board (GreenGuard PB4, which is a pretty rigid XPS) I got a sample of last week at the Pacific Coast Builders Conference. That would cut the thickness in half, still give the thermal break I'm seeking, and hopefully not impact the shear strength nearly as much. Still not a good idea?
" That would cut the thickness in half, still give the thermal break I'm seeking, "Not really. What is the assembled R-value of a wall section with and without this thermal break.From the inside you have, air boundry layer, 1/2 DW, 3.5 or 5.5" stud, 1/4" foam, 1/2 sheathing, exterior finish. It will have a relatively small affect on that section of the wall with studs and very tiny on the overall wall.
The issue with foam board between the sheathing and studs is a dramatic reduction in the shear strength of the fasteners. The extra 'lever arm' may not seem like much, but it is going to make a big difference.
I'm sure it could be engineered to compensate (different fasteners/schedule, diagonal bracing or somesuch), but the cost/benefit ratio may be out of whack.
You can put a layer of foam outside the sheathing if the assembly is designed right. You just want to avoid trapping moisture behind it. Foam beneath the drywall is another option for a thermal break. I have had success with this method in a heating climate.
"Foam beneath the drywall is another option for a thermal break."
I like that idea. I'll go with it. Thanks!
I'm thinking, sound deadening.
It's the new subfloor fastener........
velcro ;)
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