I live in Phoenix Arizona, in a typical single story ranch house with attached garage and tile roof. In the summer when you pull a car into the garage the heat of the engine (that's been pushing air conditioning full blast) and the car body (that's been sitting outside being baked by the sun) raises the temperature in the garage to the point that you could make jerky by hanging beef stips from the ceiling. While this is convienent, I'd like to find a simple way to make the garage more comfortable in the summer and go back to using the solar cooker for my jerky. :-). Two thoughts I'd like comments on: 1) Adding a fan in the garage ceiling to move the hot air from the garage into the attic and out the roof vents. I'd add a grated intake vent from a shaded area of an outside wall of the garage, low on the wall to draw in the cooler air. I've seen some simple roof fans for about $50 that seem like they would do the job, and some gable vents I could install on the wall. 2) Adding insulation in the garage ceiling to prevent the superhot air in the attic from heating the garage through the ceiling, which currently has sheet rock, mud and paint on the ceiling and walls, but is uninsulated. My concern with the insulation is that it will just trap that hot air from a car in the garage even better. I can't think of any concerns I have with adding the fan other then I've never seen it done, or heard of anyone doing it, so maybe there's a reason for that which I'm not smart enough to think of.

I have been working up to finishing my basement. I want to ensure I don't have any issues with moisture behind my finished walls and under my floor, though. My basement isn't wet, but it does feel humid down there, so I have been trying to lower the humidity. I keep a dehumidifier running 24/7. I also keep a couple vents open for the furnace/central air to help circulate air down there. The humidity runs around 45-50% with these things running. If I close the furnace vents, it goes up to around 60-65%. The exterior of the basement walls are waterproofed and have that blue polystyrene insulation over that. My first thought was that dampness was somehow getting in through the block walls, so I sealed up the wall/corner interface with hydraulic cement and applied dry-loc to the walls. This didn't seem to help the issue. In fact, it may have made matters worse as I think this is trapping the humidity in the basement now. When I close the vents and let the humidity get up to 60% or so I am gettign a little mildew on the dry-loc'd walls now. Next I sealed up all the saw cracks in the floor with caulk. This hasn't seemed to help either. If I close the furnace vents, my humidity still shoots up to 60% +. I'm trying to figure out what to try next. Any suggestions? I just can't figure out what is creating the humidity down there. Do you think the issue will be there behind the finished walls, or should I just go ahead and finish it?