Garage Heater Moisture Barrier Question

[wozz]

Hello all

Some great build threads and knowledge base I am hoping to tap into here.

New to home ownership and excited for this adventure but I have a few questions.

My house has a 3 car attached garage that I am hoping to heat with a modine hot dog 60000 btu heater. The garage has insulated walls and the ceiling finished with the exception of the first 3 ceiling joists. I am not sure why this was left open but I plan to insulate this area. Tonight poking around in the attic I find that the area above the garage that is insulated is connected to the house attic and has blown in insulation. It is sitting on the drywall ceiling and there does not appear to be a moisture barrier between the drywall and blown in insulation. Is this common?

I am wondering if I am heading towards moisture problems.

Goal for heated garage is to leave around 45 degrees F and raise the temp when I want to work out there. I am in MN. Garage door will be opened 4x a day and there are no floor drains. Two cars will be bringing in snow and the third will be stored for the winter.

Thanks in advance for any thoughts.

 

[Showkey]

Common for garage area to not have a vapor barrier especially with blown in insulation. Yes it not ideal....but rarely a problem.
Vapor barrier paint on the garage drywall is a solution if your really concerned.

 

[75gmck25]

Paint should be sufficient vapor barrier for the ceiling. Just make sure the insulation batts above are unfaced so they can let any residual moisture evaporate up into the attic.

However, also make sure you have fully sealed any ceiling (and wall) penetrations for receptacle boxes, light housings, etc. Canned spray foam from above works well in the attic, but get the low expansion foam, since the standard expansion version expands everywhere you don't want it to go. Also wear disposable rubber gloves, since that foam really sticks to your hands. You can also get rubber seals to put around the plates for receptacles in the wall.

Propane or gas heaters will generate moisture that needs to be vented, and you need to monitor the CO levels. However, you may be able to stay comfortable in moderate temps with good insulation and a small electric heater.

Bruce

 

[kTHREE]

Common for our location.
I did however primer and paint my garage ceiling as well.

Is there a reason your going with forced air vs radiant/IR? Just curious.

 

[finn]

I had an ~18000 btu Empire gas fired heater in a ~600 sf garage in Northern Illinois.

It was ok down to the high teens, but useless at zero.

I'd suggest a preemptive upgrade.

 

[wozz]

Thanks for the feedback and suggestions.

I don't care for a radiant heater that is vented into the garage.
Maybe I am overlooking something on the vented tube type but they seem quite a bit more expensive and I don't think their rise time is as fast if going from lower temp to higher

 

[6768rogues]

I have a 40 by 60 building with a 14 foot ceiling in western NY. It has a 100K BTU Reznor heater and it doesn't even breath hard to heat the place in any weather.
Is that heater you want to use listed for residential use in an attached garage? I noticed that my Reznor is and that not all their models are. I don't know what is different in the heater for residential use, but if I were heating an attached garage I would use a listed heater for the purpose.