Soil base is heavy clay, with large quantity of silica and lava-rock (there are solid Lava flows about 10 feet under, was a bear for the utility folks to cut through). I am positioned on a slope (top) which drops 4 feet over 100 foot run.
I have done the usual things (gutters, piped about 30 feet from house, re-grade, good vapor-barier, etc). I dug out a sump pump which is heavily cycled when it rains. Water comes UNDER stemwall footing, and creates puddles and mud in the center area of space, with heavy accumulation of water at the perimeter of space. Reletive humidity in space is 75%, no visible condensation, and a temperature of approximately 50 degrees F. I am going to add another layer of 10 mil plastic to floor, and eventually seal to footers. I have 2 general questions:
1. What is a reasonable humidity by temperature under my home? I have insulated floors, non insulated stemwalls. I have 5 9"x12" foundation vents (open) for approx 1500SF floorspace.
2. If de-humidification is necessary, would it work to just throw (more like labor) an un-used window-airconditioner to that space, or would I run into coil freeze-ups doing that? (I could probably rig up something to pass the heated air into the intake)
After 2 years, I am still battling this. It is further aggrivated by the fact that 100+ homes in another development 3 miles up the road are fighting mold currently.