sealing around pipes for slab vapor barrier is currently impossible
I recently built a house in climate zone 5, my first house. I tried to find a good way to seal around pipes sticking out of the basement floor but ended up using Stego tape and mastic and the result was absolutely horrendous. why bother laying out this perfect, clean Stego branded vapor barrier poly when the penetrations around the pipes are going to be a mess?
I searched high and low for a poly pipe boot but couldn’t find one. How does this not exist? It would seal pipes perfectly, it would avoid creases and gaps in the tape, it would be stronger and more flexible than either mastic or tape. It would be trivial to produce as well. Am I losing my mind? Does it exist somewhere and I just never saw it? Please help me. Not for my project, because it’s already done, but for my sanity. How do truly professional builders seal around those pipes?
I would also like to ask people how they seal around sump basins, the water line if it is coming from under the slab, and those boxes they put under showers. Thanks.
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Not sure about the need to seal at vapor barrier, but for methane barrier I've seen Tremco Vaporlock specified.
https://www.tremcosealants.com/markets/residential/methane-mitigation-systems/vaporlock/vaporlock-m/
Pipe penetration detail: https://www.tremcosealants.com/fileshare/waterproofing_details/VP-M-P-01.pdf
savannah_concepts,
Take a square of peel & stick membrane (I use whatever my lumberyard stocks - currently resisto), and cut it in half. Then cut an elongated circle slightly smaller than the pipe in each piece close to one edge. Push them against the pipe from each side, and overlap, then press down onto the poly. Take another small strip and run it around the pipe lapping the top of the two pieces.
You can do the same with plumbing vents to seal them to the underlay before installing roof boots as a secondary layer of protection.
Malcolm's technique is good.
The "box" for showers or bathtubs should be filled with concrete. That is code in my parts.
Also code says all penetrations need a sealant on top of the slab. For radon not for water vapour
We haven’t had much luck with Stego tape for anything but flat seams. Siga Fentrim is the winner for taping Stego to pipe penetrations and also sealing to concrete walls. Worth the $$
In the commercial world, the pipes usually aren't really sealed. Common practice is to either put a sleeve in (or nothing at all), then a little air gap between the sleeve or edge of concrete and the pipe coming up. Sometimes you see the concrete tight to the pipes, but it's better to have a sleeve and air gap to avoid stressing the pipe. When we need to seal around the air gap (usually to deal with bulk water), it's common to either empty a tube or too of silicone into the void and glorp silicone all over to get a "seal". The other way to do it is to use fire putty (commonly sold as "putty pads"), and mold that around the pipe to make a seal.
As far as I know, there is no commercial product made for floors. There are products made for walls though. I also like Malcolm's method, above, although I haven't tried that myself before.
Bill