I am beginning renovations on our basement. We have excessive moisture which causes mold to grow on the walls and floors. We don't have a water leak. The basement walls are block (which has a pre-existing layer of paint and is peeling in some spots)and the floor is poured cement (bare). There are cracks on the cement floors. Can you tell us what we should do to prevent this moisture problem. Should we put a treatment on the walls? Should we put a treatment on the floor?
Answer:
The first thing you have to do is dry the place out. There are only three ways to do that; ventilatel, ventilate, ventilate. There is no real treatment you can provide from the inside to keep the basement dry. To keep it dry, you might also try a system that I know works very well: 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.
