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...
godzilla Posted January 19, 2009 Report Share Posted January 19, 2009 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 ? The RH in my shop right now in the dead of winter here in Iowa is 65% to 67% according to my gauge. Quite possible that is a contributing factor. Is the attic portion insulated? Is your shop area tightly isolated from the rest of the garage, you said it is walled off and those are insulated...are the outside walls as well? The best thing to do is to add heat, if you can and ventilate. I keep my shop at 50-55 F unless I'm out there working (it's a garage as well). I have R-19 in the ceiling and R-13 in the outside walls. At my house the cars stay outside, so the overhead never opens. My guess is you need to add heat and vent the moisture out as you surmised, the problem there is you are sucking the heat out as well. Maybe someone will have another suggestion. Good luck. Steve Quote Link to comment Share on other sites More sharing options...
perhellion Posted January 19, 2009 Report Share Posted January 19, 2009 Back in the summer in NC, I had a problem with high humidity. Did a little internet research -- turns out it is hot and humid in the south in the summer -- surprise. Anyhow, one interesting idea I saw (which, in my case had the disavantage of adding hot air but would be good for you) is to use a fan and ductwork to move air from the top of your attic to your workshop. The air is warm, dry, and nearly free. Quote Link to comment Share on other sites More sharing options...
govtmule Posted January 20, 2009 Author Report Share Posted January 20, 2009 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 ? The RH in my shop right now in the dead of winter here in Iowa is 65% to 67% according to my gauge. Quite possible that is a contributing factor. Is the attic portion insulated? Is your shop area tightly isolated from the rest of the garage, you said it is walled off and those are insulated...are the outside walls as well? The best thing to do is to add heat, if you can and ventilate. I keep my shop at 50-55 F unless I'm out there working (it's a garage as well). I have R-19 in the ceiling and R-13 in the outside walls. At my house the cars stay outside, so the overhead never opens. My guess is you need to add heat and vent the moisture out as you surmised, the problem there is you are sucking the heat out as well. Maybe someone will have another suggestion. Good luck. Steve Yes, the attic portion is insulated. The main garage walls are all insulated and the two overhead doors. The wall that I put up between the two main stalls and the third stall (my shop) is NOT insulated. Just drywall on the garage side and open studs on my shop side. I wouldn't say that the shop is tightly isolated from the garage. Quote Link to comment Share on other sites More sharing options...
govtmule Posted January 20, 2009 Author Report Share Posted January 20, 2009 Back in the summer in NC, I had a problem with high humidity. Did a little internet research -- turns out it is hot and humid in the south in the summer -- surprise. Anyhow, one interesting idea I saw (which, in my case had the disavantage of adding hot air but would be good for you) is to use a fan and ductwork to move air from the top of your attic to your workshop. The air is warm, dry, and nearly free. That internet....it knows EVERYTHING If the air is warm enough up there to make a difference for me I think this is a good idea. This way I don't have to cut a hole in my roof or in my existing vent PVC but I don't think the air up there is warm at all this time of year. Quote Link to comment Share on other sites More sharing options...
Woodenspoke Posted January 20, 2009 Report Share Posted January 20, 2009 It is certainly due to the heating cooling cycle. Your space heats up the moisture is released then when it cools the moisture gathers at the top of your space where the humidity and heat lingers the longest. First thing is eliminate any moisture from the space. If you are drying green wood put it elsewhere. Add a dehumidifier and use it when you heat your shop. Empty the dehumidifier water when you turn off the heat. Keep the door open to vent moisture back into the garage when you are not using the shop. First its a garage never an ideal space in most US locations, it is not sealed like your home, walls and insulated doors will most likely not help. Without a complete weather seal on the shop and constant climate control like heat you are at the mercy of the weather. Quote Link to comment Share on other sites More sharing options...
godzilla Posted January 20, 2009 Report Share Posted January 20, 2009 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 ? The RH in my shop right now in the dead of winter here in Iowa is 65% to 67% according to my gauge. Quite possible that is a contributing factor. Is the attic portion insulated? Is your shop area tightly isolated from the rest of the garage, you said it is walled off and those are insulated...are the outside walls as well? The best thing to do is to add heat, if you can and ventilate. I keep my shop at 50-55 F unless I'm out there working (it's a garage as well). I have R-19 in the ceiling and R-13 in the outside walls. At my house the cars stay outside, so the overhead never opens. My guess is you need to add heat and vent the moisture out as you surmised, the problem there is you are sucking the heat out as well. Maybe someone will have another suggestion. Good luck. Steve Yes, the attic portion is insulated. The main garage walls are all insulated and the two overhead doors. The wall that I put up between the two main stalls and the third stall (my shop) is NOT insulated. Just drywall on the garage side and open studs on my shop side. I wouldn't say that the shop is tightly isolated from the garage. I would say if you can tighten up your shop and add some more heat that should make a big difference. You have to be careful, if it is that humid you have the possibility of mold and/or mildew forming and you don't need that. Steve Quote Link to comment Share on other sites More sharing options...
guitar101 Posted January 20, 2009 Report Share Posted January 20, 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 30 Degrees Farenheit is below freezing. Seems to me you have to heat your garage. If you turn off the heat when you are finished working the moist air that rises is condensing on the ceiling and as the temperature drops it freezes. To my way of thinking if you let the inside temperature drop below freezing it doesn't matter how much insulation you have it doesn't do a darned thing. I live in Northern Ontario so our winters get very cold. I have R-45 in the ceiling and R20 in the walls of my attached garage that I built this summer. I keep my cars outside since this is going to be my workshop. Like Godzilla I keep it at about 55 degrees unless I am working. Do you have a concrete floor?? Heating and cooling a concrete floor can cause it to crack. Better to keep it at a constant temperature. Quote Link to comment Share on other sites More sharing options...
joshvegas Posted January 20, 2009 Report Share Posted January 20, 2009 http://www.ecamo.co.uk/image-viewer.php?im...mo+Umbrella+Hat Quote Link to comment Share on other sites More sharing options...
govtmule Posted January 20, 2009 Author Report Share Posted January 20, 2009 Do you have a concrete floor?? Heating and cooling a concrete floor can cause it to crack. Better to keep it at a constant temperature. Good point, thanks. I've thought about splicing into my homes forced air ductwork and running a supply over to the ceiling of my shop just to cut the chill out of the air and hopefully keep the temp a bit more stable in there but I have a whole house humidifier on my furnace so I thought the extra humidity that I would be intorducing out there would do more harm than good. Quote Link to comment Share on other sites More sharing options...
govtmule Posted January 20, 2009 Author Report Share Posted January 20, 2009 http://www.ecamo.co.uk/image-viewer.php?im...mo+Umbrella+Hat Sweeeeeet.....in camo even !! Nice. It's always the low tech solution that's the best !! Quote Link to comment Share on other sites More sharing options...
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