Do You Need to Tape & Seam Seal XPS Over 6 Mil Poly in Basement?
cloves2016
| Posted in General Questions on
Hi everyone,
I had a question. I live in NJ zone 4. My basement is 4 feet underground and 4 feet above. I am doing an XPS reto install on the interior walls. I put down a 6 mil poly (5 inches up on all walls) and then 2 inches of XPS on the floor and lower walls. I have been using Dow Spray foam inbetween the wall of XPS and the XPS on the floor.
Do I need to seam seal all the joints using Tyvek tape (both wall and floor)? Or does the 6 mill poly below the floor eliminate the need to seam seal?
In the picture attached you can see the poly comig up from the floor. The black stuff is foundation coating (used to hold up the poly)
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Replies
Dan,
You'll hear builders argue in favor of both sides of this question. If you have 6-mil poly under your rigid foam, you aren't going to get much air leakage through your floor assembly. But tape is relatively cheap, and many builders prefer to make their air barrier redundant.