Garage Condensation


Old 12-14-16, 09:16 AM
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Garage Condensation

I am out of ideas and all the 'do's and don't' I have come across I have followed and my garage still gets condensation on the walls in the winter. Is there something I'm missing or is it just because it is so cold there is nothing to do about it. I live right outside of Chicago.
- I do not run the cars in the garage
- Laundry room dryer vent does not vent into the garage
- I added blown-in insulation in the attic over the garage(no vapor barrier)
- I added batt insulation and drywall to the walls
- The garage door has insulation panels
- I added a new weatherstrip around the exterior of the garage door
- I added a new weatherstrip to the bottom of the garage door
- I added a new weatherstrip around the door leading from the garage into the house.
- My garage floor is painted/epoxied

I think I've covered everything. And I run a little oscillator fan in the garage to move the air around and I went out this morning and there is condensation on the ceiling, on the inside of the garage door, and on the side door leading outside. Is there any other reason as to why this is happening or anything I can do to fix it or is it because it is too damn cold outside??
Old 12-14-16, 11:25 AM
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Let's start with the obvious, condensation occurs when warm moist air comes into contact with a colder surface. Almost instantaneously, the air temperature at the surface drops, creating moisture or condensation.

Thus, you need two components for condensation: relatively warm, moist air and a colder surface. Get rid of either one and you're home free. You seem to have done much of what you could on the temperature side, with (probably some but) insufficient results.

I'd attack the moisture component, which is tough to do. For example, a wet car brings in significant water. The simple answer to me seems to be a dehumidifier.

BTW, keep in mind that moisture can have a detrimental effect on everything around it.

Tony P.
Old 12-14-16, 03:32 PM
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I wonder if the house (or at least the shared wall) is under positive pressure and that the warm humid air is coming from what is leaking from the house. Any outlets in that shared wall?

If your batt insulation was kraft faced, that certainly isn't helping... it would be trapping moisture inside the unheated garage.

A dehumidifier might help, but i would guarantee that a small 240V electric garage heater placed overhead in a corner would solve it. Setting the thermostat at 45 or 50... whatever it takes to keep the garage surfaces above the dew point.
Old 12-14-16, 04:12 PM
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On reflection, I prefer the heater solution in that heating the garage would make it more useful, as well.
Old 12-14-16, 05:51 PM
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Hi kody,
The big question is, do you bring in snow covered or wet vehicles? That would be a lot of moisture and with no ventilation it has to go somewhere. I suspect that the outside air is dryer than what is inside your garage, thus opening a window will reduce the moisture (ventilation).

Sealing and insulating the garage as you have done should be followed by some level of heating, as suggested. But just adding heat does not remove the moisture, other than when the garage door is open.


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