tape the plastic/ eps?

[SDPrairie]

Hi all

Been lurking a couple months- first post. Really lots of great people and info on this forum. I'm building a new house and garage and am placing pex for possible future radiant in floor heat. I have read many posts here for input. One thing I haven't been able to find info on is whether folks recommend taping the 6 mil plastic under lay and/or the EPS sheets. If yes, what kind of tape are you using? Also, it doesn't look as if people are covering the last 6 inches of vertical concrete of the garage walls between the slab and where the stcik built wall starts. Is it becasue there's no good way to cover it and no one wants a pink strip and their garage? I really enjoy all the shop talk. Thanks much, SDP

 

[Steve in Mi]

Hi all

Also, it doesn't look as if people are covering the last 6 inches of vertical concrete of the garage walls between the slab and where the stcik built wall starts. Is it becasue there's no good way to cover it and no one wants a pink strip and their garage?

Welcome!

The perimeter between the slab inside the foundation walls and stick framing can be a weak link in the insulation package and also the edge of the slab needs attention to provide a thermo barrier. In my build I ran 1" Dow rigid foam on the exterior of the foundation from the footings up. Actually continued that 1" foam all the way to the peak of my 2 story shop. I use aluminum flashing to cover the foam between the ground and exterior siding. On the inside 1" foam from the footings up the inside of the foundation block and a bit into the floor pour which sets on poly and 1" foam. Above that I used typical tar soaked expansion joint material for the thermo break. That was in 1982, today, I think the preferable treatment may be running the foam along the edge of the cement floor and bevel cutting it at 45 with the top edge flush with the finished floor.

I did not tape the foam or film. Poly film had ~ 4' overlap down the center of my building and the Dow rigid foam was tounge & groove with a good tight (wedged in) fit all around. Above ground the edges of the foam boards were glued with Dow Corning mastic 111. Today, the use of tyvek would make gluing unnecessary IMO.

 

[SDPrairie]

Thanks for the info on your set up Steve

I have a brother in MI putting radiant in his shop next year. He'd enjoy this forum also.

 

[BJR]

I did, I used "tuck tape" from Lowes. It was expensive, IMO and I'm not sure it's really worth it. If you overlap the vapor barrier and run the EPS perpendicular there should not be an issue.

I didn't know the final height of my slab so I was conservative on the insulation up the sides.