I am having a new house built with an attached garage just to park in. The garage will be insulated and sheetrocked but no heat. My contractor says that I must put heat in the garage because I can not let the sheetrock freeze. I have lived in colorado all of my life and have never heard of such a thing. Do any of you guys know anything about this???
thanks, john
p.s. and I don't mean just while the mud is wet.

 

My Dad converted a 14 x 28" carport into a 30 x 28" garage, about 20 years ago. The exterior is brick (to match the house) and the walls are 6" thick.

He added R-19 insulation (at my insistance) in the walls and R-30 in the attic and the garage is drywalled, taped and painted. He has two garage doors on the front wall, and one on the back wall. The garage is unheated and not air conditioned.
In the summer, his garage NEVER goes above 80° - and in the winter, never below 40°. (He lives just south of Washington, DC.)

My 2¢.

 

Same here, an attached two car Garage fully insulated, an extra large garage door that gets opened at least twice a day. Its never gone below 40 unless someone leaves the door up for extended periods. In the Summer it will hit the mid 90's I've had a few seams pop, but the same thing has happened in the house. PS in the Winter we keep soft drinks, bottled water, fruit, etc in the garage, and they've never frozen. You could also put foam insulation around the foundation down to about three foot to make the slab keep its heat.

 

I agree with your builder and as a contractor here in North country I would never recommend the use of drywall in an unheated space. Insulating an area that isn't heated is also waste of money. Insulation doesn't make an area warmer or cooler just by being there. Insulation works to keep heated spaces warm and air conditioned spaces cool, with the proper ventilation system. Drywall is extremely porous and will suck up any moisture thus causing a damp moldy mess in humid climates and crappy looking joints in areas with cold winters when the joints move.
Either heat the garage if you decide to use drywall, apply plywood or some other dense material for the walls and ceiling if you don't heat the space, or hire a contractor that will do whatever you want even if it's a bad idea.

 

It would seem to me that the moisture content of drywall would not allow it to 'freeze'. Given that the gypsum in the wallboard already is in a solid state, I can't see how it could 'freeze'.

I am however no expert in drywall and would love to hear a couple of pro's answer.

 

If its a two car garage he will park two Giant heaters in it every day, not to mention the heat leaking thru the house walls. Might as well trap that heat. Also around here it is illegal to put up plywood, paneling or other flammable materials in a garage. One of the plastic goods manufactures, has a system of panels for the garage that shelves, cabinets, tool racks, etc. hook into. Its illegal to have too much of that stuff in a garage, do to the flammablity of the stuff and how much smoke it would release.

 

Also what part of Colorado do you live in? I had to go and work a job out there in Jan. Expected to freeze my A** off. It would snow really hard and two days later it be in the mid to upper 70s. The locals said that was typical of the weather.

 

i can only think that your contractor was referring to keeping the sheetrock and spackle warm untill they were fully dryed, but after that they are fine. insulation is inexpensive, and usefull for those projects that require temporary heating or cooling.
fire code in our area requires fireproof walls (sheetrock) and doors in garages.

 

I'm very confused on this heated garage/frozen sheetrock question. Once the sheetrock has been taped and sprayed and allowed to dry it has some what sealed itself. The only reason you would get cracks in it is if the house actually moves. The sheetrock does not move or grow with the change in weather like wood does. I spent 15+ years delivering "rock" in the southeast corner of Wisconsin and there was always a few sheets left in the garage to be used as a firewall. Some homeowners did cover all the walls but from the starter homes up to the multi-million dollar homes they all had a firewall between the garage and house. I'm sure a larger % did not have heat in the garage area than did. Finish off the garage with what ever you like, but no need to worry about heat with sheetrock. And if you do decide to finish it all the little bit of insulation in the walls and ceiling is a small investment for the future when there might be a heater in your future.

 

If there are rooms above the garage, it may be in your interest to add some heat in the garage. Cost will depend on the type of heating system you have. The floors in the upstairs' rooms will stay warmer and take less energy to heat. The additional costs to add the heat in the garage will be offset eventually by taking less energy to heat the rooms.
I don't think anyone is saying the drywall itself will be ruined by freezing temperatures, it is the tape joints that will start looking bad after a while.

 

Follow-up to my post. . . .

Here in So. MD., code states that IF there is 'living space' above a garage, the garage MUST be drywalled. ( For a Fire barrier.) Nothing is said about insulating the garage space. (Mine isn't insulated. I wish it was.)
The master bedroom is above my garage. In the summer, the bedroom floor stays warm. In the winter, the floor stays Cccccoooollllld. Through convection, that makes the M-Bedroom chilly in winter / warm in summer.

My intention is to rip down the drywall in the garage (eventually) and insulate the area with the most effective (R-rating) that I possibly can.

An additional 2¢.

 

The building code allows ordinary living areas to be surfaced with plywood, barnboard, tounge-n-groove, etc. The flame spread and smoke developed ratings of ordinary wood are low enough to be accepted. There is no issue with total amount of wood siding.

A garage in which vehicles may be parked has to be isolated from the living space by a 15 minute "firewall". This can be met by a single stud wall with ordinary 1/2 inch drywall on just one side. (It isn't met by plywood, although you can put plywood under or over drywall). I believe the one side with plywood can be the interior wall, but am not sure. Some jurisdictions have additional requirements, such as drywall on both sides, or 5/8 firecode drywall, etc, but these are not part of the International One and Two Family Dwelling Code, which is the starting point for most residential codes these days.

If there is not living space above the house, and if the garage roof can collapse without compromising the rest of the house structure, then there is no general nation-wide building code requirement for the exterior walls to be fire rated. They can be unfinished or covered with plywood. Paper faced insulation must be "in contact with a continuous wall covering", as the material explicitly requires it and the flame-spread rating of kraft paper is too high anyway. Foam insulation must also be covered due to problems with "smoke developed".

If the living space is above the house, the ceiling must be fire rated, and the walls must also be fire rated since they support that celing. In this case you must put drywall on the ceiling and 4 walls.

If your garage abuts the house, and if you are not in North Dakota or some other severe cold climate, you can insulate the garage, not heat it, and it will stay above freezing just from the heat leakage from the house. I personally would put drywall over the insulation and fire-tape it just for the safety benefits. (Besides, drywall is cheaper than plywood). This is the standard practice in places that get fairly cold, such as New England. I would not worry about damage from freezing or from moisture absorption.

 

Thanks for all of the info. My new house will be in western Colorado near Grand Junction. It is normally pretty dry here. Most years we have a few days above a 100 and a few days below 0, but most of the time it is pretty nice. We haven't had a bad winter in about 10 years. The last couple of years I have washed my truck in jan. without a coat on. There will be no living space above the garage so that won't be a concern. My dad has a garage thats close to 30 yrs old that was drywalled but not taped or painted. The sheetrock still looks ok to me.
Thanks again, john