Basement Garage with Concrete Slab: To Vent or not to Vent
Cool masonary surfaces and high humidity equals condensation, which gives rise to mold/mildew. To test for hydrostatic water pressure under the floor, tape a 16" piece of aluminum foil or plastic to the floor, seal all sides. Check after 2-3 days, if dry, you cna do most anything you want with the floor; damp, you have a small problem and the floor will need special treatment for any type floor covering; wet, forget it, major work to instll floor coverings. Wall can be insulated with rigid foam, but it must be covered with drywal for fire code. Owens Corning, the pink stuff, has a 2" foam with slot in the panels for furring strip. Tapcons secure the foam/furring strips to the walls, and yiou can install drywall directly to the furring strips.
Ventilating a garage can be tricky, depending on fire codes. Wall openings between living space and garage are carefully regulated to prevent fire travel. I found nothing in IRC about openings to the outside, provided there are no combustible materials around the opening. So a vent fan to the outside might be OK, check local code.
Last edited by Just Bill; 05-29-2009 at 07:19 AM.