[435Studio]

When I look at the wall between my basement and the crawl space there is foam board insulation on the crawl space side. There is also some kind of black sealant on the wall as well. What impact would this have on insulation and vapor barrier on the inside of the basement walls?

[twinkiedooter]

The black sealant is supposed to be there. It is a waterproofing agent. It's basically a tar product.

[amsteube]

The black layer is a spray on vapor barrier. I hesitate to call anything water proof because almost nothing is 100% water proof.

The foam insulation serves a couple of purposes.
1) When pouring a basement foundation many companies will put a rigid insulation board inside of the formwork for the concrete because they can leave the insulation there and it is much easier to strip the form work.
2) It will provide some insulation but not a lot. If you use the basement as a living space you need to put insulation inside the wall with an air cavity between the wall and the insulation.

Aaron

[21boat]

The black sealant should be on the outside of the wall below grade level to protect the block wall form ground moisture. Inside is a bit back wards.

The foam can be on either side depending on grade.

Your fine as long as the wall outside is above grade.

Signed 21 Boat

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[ballengerb1]

No impact at all. Are you planning to addition insulation or something?

[435Studio]

I plan on framing a wall set out from the concrete wall. I have taped plastic to the wall for three days, not a trace of moisture. Is is necessary to seal the concrete walls, or add any other vapor barrier between the concrete and insulation I plan to add the new framed wall. I need to check, but I believe code requires vapor barrier between insulation and drywall.

[ballengerb1]

Since you mention code will you be pulling a permit?

[435Studio]

Already have it.

[ballengerb1]

OK then, check the permit carefully, the building department will guide you on how this should be done since they will inspect it. Its much better to get on their good side by asking advice that to ask their pardon after an error. My area requires the patio to not be pinned and it must float. A pad will more significantly during seasonal changes as compared to your homes foundation.

[435Studio]

Got it, thanks!

[luckycharm1978]

It depends on how thick the foam is on the outside as to what its purpose is there are how do I put this "ready made" forms that are sometimes made of foam that some contractors use and they just leave the foam in place supposed to be insulation. As for the black tar not a good idea to put it inside your basement. Its supposed to be for waterproofing on the outside. As long as the drain tile is properly installed you should have no problems with moisture.