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with a Mr. heater mh18b portable propane heater with it dry my garage


mikecsti's Avatar
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01-12-18, 05:43 AM   #1 (permalink)  
with a Mr. heater mh18b portable propane heater with it dry my garage

I need to come up with a way to dry my garage from moisture. it's always damp this time of year because of the car coming in wet with snow. The garage is insulated and it's half buried on one side. the other side is the family room and bedrooms above all that's insulated. The garage says at about 50 degrees in the winter time. I tried dehumidifier but it's to cold for them to work they just seem to run and not take out the moisture. So I was thinking heating it with a Mr. heater mh18b. I know it will heat up the garage but will it also dry it back? The garage doors and concrete wall has moisture sitting on it. The humidity gauge I have in the garage always reads 70 and up. My tools get rust on them all the time from this. Tried portable electric heaters and they do not do much.

Or do I need something else?

Thanks

 
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01-12-18, 06:11 AM   #2 (permalink)  
No, that will actually add moisture to the garage. Any vent free heater produces water vapor as one of it's exhaust gasses. You will need a electric heater or a fuel powered one that vents the combustion gasses outside.

One of the worst things for causing things to rust is condensation. So, it's not totally about the humidity. It's whether or not it condenses into liquid water. Worst is when you have a long cold period so everything in the garage gets thoroughly cold soaked. Then you get a warm, humid day. When you open the garage door all the warm, moist air hits the cold surfaces in the garage and condenses into liquid water. That's when corrosion really gets going. It may seem counter intuitive but when you do get a warm day but sometimes it's better to leave the doors closed

 
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01-12-18, 07:04 AM   #3 (permalink)  
okay, so my best bet is to get one of those DIY ac/heat units. that hang on the wall and the exhaust and water go out to that little unit out side.

 
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01-12-18, 07:19 AM   #4 (permalink)  
No, imo the best thing you can do is get a few fans and always circulate air.

The reason it is wet is not just because of the car bringing it in... its because the ground is colder than the dew point in your shop. And your slab is probably not insulated. If you warm the room, you will likely make the problem worse. Warmer air almost always means a higher dew point, sonce warm air can hold more moisture. The floor is acting like a dehumidifier coil, causing the warm moist air in your garage to condense on the comparatively cold floor.

You could also look into venilation, your roof could be trapping moisture if it is not vented.

 
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01-12-18, 08:52 AM   #5 (permalink)  
Dew point is a function of how much water vapor is in the air. It is the temperature at which the air can hold no more water. When the temperature of objects in the room is below the dew point condensation/dew will form. If you warm the garage above the dew point condensation will not form. None of this alters the amount of water vapor in the air though. It only affects condensation and how humid it feels. By heating the room you increase the difference between the temperature and dew point. This lowers the relative humidity and makes it feel dryer.

 
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01-12-18, 09:10 AM   #6 (permalink)  
The reason I'm saying heaters may make it worse is that the concrete will probably always be cold (below dew point) in the winter. The ground is like a heat sink... the ground is frozen outside, and even under the heated portion of the garage the ground is probably 45F. When you heat the garage, the heat rises but the floor stays cold. You can heat the garage to 70F but I'm betting the floor is only 50F or so. So unless there is a lot of air movement to circulate that air around, the concrete will be cold and wet. And the condensation on the concrete is likely the main source of the moisture in the garage.

Warming the garage may help the tools not get wet though. If the temperature of all the objects in the garage is higher, then yes, they should stay dry because their temp will be above the dew point. But with such high humidity there is probably only a few degrees difference. Open the garage door and it chills everything... and it will condense. Just like your glasses fog up when you come inside from the cold.

 
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01-18-18, 08:19 AM   #7 (permalink)  
My garage doors are wood. There always covered in water too. It just pours off when I open the garage door. Would it be better if I buy new insulated garage doors and windows? The windows are also the original and do not open. We are talking 55 years old here. Another option is if I dig up the foundation wall, add a footing drain and reseal the wall and put on 2" ridge board insulation would that help too? Or put in a like a exhaust fan in the garage? Or all the above?

 
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01-19-18, 07:21 AM   #8 (permalink)  
A natural gas or propane ceiling mounted heater by Modine, Reznor, or Mr. Heater would be a great investment and heat your garage very well. My preference would be a sealed combustion unit that will work in an area that has combustibles present. If one of these will be your choice please read and follow the installation directions.

 
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