govtmule Posted January 19, 2009 Report Share Posted January 19, 2009 My shop is a third stall that I walled off from the main garage. The side walls are insulated and the overhead door is foam insulated. On the coldest days the temp flirts with the freezing mark but is usually in the high 30's, low 40's. Actually last week it got down to -29 with a wind chill of -50 and the shop temp was around 30. BUT...in the winter I see frost build up on my shop ceiling where the coldest side wall meets the ceiling. And if I turn on my heater to work out there, that frost melts and then drips down onto my shop floor, work bench, and worse, onto my wood storage racks. What I think is causing it: I think that the warm cars being parked on the other side of the wall, and the dripping snow off of those cars is causing humidity in my shop to rise up and collect on the ceiling where it freezes because that side wall is not protected from the wind outside and is by far the coldest wall. Sound possible ? I've had a contractor crawl up into the roofing and verified that there is no moisture coming in from above or outside and dripping down onto the garage ceiling so the moisture seems to be coming from below the ceiling, not above it. The RH in my shop right now in the dead of winter here in Iowa is 65% to 67% according to my gauge. That seems a bit high for the winter to me and I only notice it that high in the winter. So either my gauge is off or my concrete floor is radiating a bunch of humidity up to my ceiling. So if that sounds like a likely cause for the shop rain, how the heck do I cut humidity other than a de-humidifier. I'm afraid that the de-humidifer would freeze up out there. What if I hooked up a bathroom type exhaust fan into the ceiling and hooked it into the nearest bathroom exhaust tube (not sure of the proper name) heading out through the roof ? Any thoughts from anyone on the cause or fix ? Steve Quote Link to comment Share on other sites More sharing options...
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