Houzz Logo Print

Water barrier for concrete fill basement bathroom drain install

2 years ago

Context: Installing a toilet drain under concrete for basement bathroom. Dug out a rectangular hole 3ft x 1.5ft, by cutting 3 inch lines then sledge hammered the rest. Concrete is about 5-6in thick. There was a 10mil plastic membrane under the concrete then gravel. Discovered there was standing water just at the top of the gravel. This was due to the sump basin on the opposite side of the house being lifted 6 inches higher (looks like it floated/heaved up before we bought the house and we just didnt realize.) we reset the basin and after 24 hours of the sump running almost non-stop, the water in the hole went down about 6 inches.

My question: When I finish the drain pipe install, and replace gravel(also adding some rebar/dowels which I'm aware may be overkill). I would like to replace the 10mil plastic water/vapor barrier since that area is definitely. My concern is there is no good way to get a proper seal with the existing 10mil, so is there any other product to use in place? The goal is to (1)protect against water wicking up into the new concrete, (2)keep water vapor at bay and (3)do it without creating a pocket that will unintentionally trap water against the concrete if water does rise.

I've looked at spray foam, but couldn't find solid info. I could just lay plastic so its slightly domed over the pipe to decrease water but not waterproof.

Comment (1)