I have a large basement w/ ceiling heights ranging from 7'7" to over 11'. Concrete poured 2 yrs ago. No leaks, or wet spots, but I can "feel" the damp air sometimes. I will be building approx. 500 ft of wall space w mostly 2 x 4. Should bottom plate have foam or plastic,or other placed underneath? Same question fro for planned carpeted, stone tiled, and carpeted room floors? What about wall protection with plastic, insulation? I keep reading so many contrary ways of using, and not using above water protecting ideas. Is subflooring needed for above?
Answer:
I still don't believe in sub-floors in a basement but you can get rid of the humidity. Cold air holds more moisture than warm air and is, therefore, heavier. As air cools, it falls and keeps falling until it reaches the lowest level in the house. It cannot fall beyond the basement floor and that is where it has to be collected and pumped outside before that moisture gets a chance to condense in order to get rid of the moldy, musty odour and/or avoid it in the first place. A booster fan (250 CFM +) is available as a ‘pop in’ unit to fit 4”, 5” or 6” round heating duct. This can be installed in a totally separate duct line that is at least six feet from the nearest heat source. A timer on it will ensure that it operates only during the night (9pm to 9am) so cold, moist air it pumps out is not replaced by air that brings in even more humidity from outside. All joints and seams in the duct are taped and sealed for maximum efficiency and rather than a heating-type grill it should be a return air-type grill. To avoid having to core another hole in the foundation wall, this system can be vented, via a “TY” through the clothes dryer vent. Because none of the doors in the house go all the way to the floor, cold, moist air should find its way to that grill.
