Humidity / Moisture Solutions

[AndyCFI]

Hello,

I am a longtime lurker. I finally got my own 996 square foot detached garage when we bought our house last year. It originally was a 2 car, and had a third bay added on later. The old exterior wall was kept and separates the single bay from the double bay. I want to turn the single garage into a man cave next to my shop.

It is currently insulated and paneled and has a gas wall furnace. The problem is that the room is usually quite humid and has a strong, musty, moist odor. I have already decided to reinsulate and put greenboard up. What can i do to prevent moisture going forward?

So far, I am considering a vapor barrier and possibly a roof vent to equalize outside temperature and humidity. Any suggestions on the best vapor barrier / venting method?

Thanks,
Andy

 

[JCfreak]

Where are you located? Where is the moisture coming from? It sounds like you are over insulated as it is. Venting roof?

 

[BigSteve63]

Had the same problem in a previous shop. Shop heat was a ventless gas wall furnace. By the manufacturer's specs, it considered an "open" space and needed no venting. The building was so tight that the O2 sensor on the heater would shut it off. Had a lot of problems with humidity. Found out that gas heater produces quite a bit of moisture as the gas burns, causing the floor and all metal items to sweat badly. Finally removed it and replaced with a down flow wall heater that brought in outside combustion air and was vented through the roof - problem solved.

 

[AndyCFI]

Thank you for the replies. I have been offline for a few days. I am located in Cleveland, Ohio. My wall furnace is actually vented, I forgot to mention that. The humidity isn't so much from the furnace, it is more from the environment and is most pronounced during the warm months. I have no objection to running a dehumidifier fulltime, but would like to construct the new interior walls, insulation, and vapor-barrier in such a way that moisture will be minimized by design.

By roof vent I meant allowing some exchange with outside air. I've read that equalizing the inside and outside air can prevent some condensation. Any other ideas on where this moisture is coming from? The concrete floor? Condensation?

 

[D45]

Whats the difference between a moisture barrier and a vapor barrier?

When should one be used over the other?