Moisture, Mildew

Old 01-18-01, 06:53 AM
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Hi all,

I will be ripping my 60's era panelled, uninsulated, unheated basement out this spring.

This is not the first basement I have done, but, I'm trying to avoid a problem I had experienced in the last basement refinish with moisture, and mildew.

Basement is 3-4' below grade. The last basement I refurbished was also 3-4' below grade, with NO leaks, or water problems. to do the job right, I Thoro-sealed the entire basement....all walls, and floor. This Thoro-seal is supposed to seal the concrete. It is applied with a big paint brush, and dries like a cement. Well, I sealed the walls and floor, then used steel studs (2X4) for the walls, and installed 2" thick foil faced foam boards between the studs 16"OC, and put 1/2" green board up (Water resistant sheetrock). The walls were built out from the concrete foundation approximately 3-4". I also installed a new heating zone, then, installed 14' of High Output baseboard (hot water). The floor had moisture resistant padding with carpeting install over it.

Then I put a drop ceiling in, good stuff, with foil backed 2X2 panels.

I still had a dampness, and mildew problem down there. I then proceeded to rip out the new basement window (1 of the two NEW windows), and installed an air conditioner. It helped the moisture and dampness problem during the summer, but in the spring and fall, when your not running the heat or AC, the moisture problem came back.

So, short of being relegated to running a de-humidifier (Which you probably guessed I am trying to avoid), what the heck can one do to insure this does not happen again? I went through considerable work and expense to insure the basement was well sealed and insulated, only to have it smell like damp, mildew. Yucch.

The one difference between my old basement, and the one I will be doing now is, this house has Central air. The basement has a duct coming down to the basement, which supplies cool air, but it does NOT have another duct to the return air (Which I will do, cause it aint' working right if the air is not being exchanged).

So, anybody out there see something I didnt do right to avoid this again? I'm certainly at a loss.

Old 01-18-01, 07:22 PM
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Maybe when you insulate your walls you can put a plastic 4 mil. vapor barrier up instead of the foil faced. It might be a tighter seal.Other than that your sound like you got all your bases covered.One more tip, I hold my drywall off the floor a 1/2 inch in case of possible water leaks.I see alot of basement with drywall damage at the bottom of the sheets.
Old 01-20-01, 05:16 PM
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Moisture can come from many sources

Moisture can come from many sources. Concrete is porous to the extent that water can seep though. Stopping the water from the inside (as you tried with the sealant paint) is temporary at best. The only effective method is from the outside.

Other sources are cooking, a lot of plants in the house, vent-free fireplaces, venting the dryer in the house.

To see how really dry your basement is, tape a 3' x 3' piece of plastic to the wall. Tape another to the floor. Tape all the edges. Leave it for several days. If you see moisture between the palstic and the concrete, you have a moisture problem that sealing the inside will not solve long term.

If you live in a humid area, you may need to run a humidifier.

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