basement & drylok

saturn78

Hi,
I live in a 50 year old house in south-central PA. I'm doing my basement remodel. The basement earlier had wood panels with no insulation between the blocks and panels. Though the blocks inside was dry, the panels in one corner had something similar to mold/mildew in when I removed it.

Now, I'm planning to insulate and drywall the basement. I'm using a paper-backed insulation and I'm also using DRYLOK (from homedepot) on the walls. Questions below

1) Apart from the DRYLOK and the paper-backed fiberglass insulation, do I need any other vapor/moisture barrier?

2) The basement is 1/2 above ground-level and 1/2 below ground-level. Do I need to put DRYLOK all over the walls or just the part that is below ground-level?

Thank You very much for the time.
Joel

Just Bill

Below grade, I prefer to use 2" rigid XPS foam panels, fiberglass can accumulate moisture and then become useless and moldy. If the walls have been and are dry, drylock may not be needed, but certainly can't hurt.

Gary in WA

I would insulate the Building Science way: 1" or less of EXP glued to the concrete with a stud wall and unfaced batt insulation (I suggest rock wool) with drywall and latex paint.
http://www.buildingscience.com/documents/digests/bsd-012-moisture-control-for-new-residential-buildings?full_view=1

My thoughts, no Drylock. You want the moisture to come through the concrete wall unrestricted, go slowly through the foam board to dry to the inside as vapor. Any inside covering on the wall would inhibit the water there and it would find another path, maybe under the wall/footing joint resulting in a wet floor. As concrete is like a sponge, the wall would wick moisture to other areas until it finds an access point. Without a coating, the water just gets that small area of wall wet and can dry to the inside. With the coating, the whole wall (or a much bigger section) would get wet and the water may build up to soak more wall before finding a small area that the coating isn't as thick to penetrate there. You would get more volume of water in a concentrated small area., possibly taking longer to dry and creating other drying problems. I have not research this yet, just my thoughts.
Be safe, Gary

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