My house has a descending driveway that leads into a basement-level garage. Immediately above the garage is my kitchen, so that the ceiling of my garage is the floor of my kitchen.
For whatever reason, there is no insulation in the ceiling of the garage, even though the garage gets pretty darn cold in the winter, leading to really cold kitchen floors. I am considering in the next couple of weeks taking on this challenge myself by installing installation between the joists (which are all currently exposed) in the garage, and then installing drywall to finish the garage ceiling.
I have a rough idea for a plan, but I have some questions. Mostly, I’m not sure what R-value I should be looking for and I’m not sure about the whole vapor barrier thing at all. Can anyone offer some helpful tips?
This will tell you what R-Value. If you are using batts, it will usually (but not necessarily) have a facing on one side that is a “vapor retardant”. This always faces the living areas.
Make sure you get the right width insulation (measure the distance between joists).
What size joists? Generally, if it’s a cold weather climate, it wouldn’t hurt to put in as much batting as you can without squishing it. Squishing it actually decreases the R value. I guess I’ve never seen a vapor barrier on a ceiling.
This is good advice. If the joists are to shallow (not likely) to allow enough insulation, you might be able to add some rigid foam insulation to the garage cieling.
Also, how old is the home? It is possible that this is a building code violation, and the builder may be on the hook to correct it…may not be worth the hassle though, as if the garage cieling isn’t finished (drywalled) then this is a pretty simple and cheap DIY project. DO invest in some disposable coveralls and respperators to cut down on the itching.
Vapour Barrier goes on the warm side. It prevents humidity from working its way through the insulation and condensing when it gets to the cold side. The condensation can cause problems like rot and mould. Trying to wrap the floor/joists with a vapour barrier can be done, but you’ll use a lot of plastic, and it will be a pain to do without leaving gaps/holes in the plastic.
The garage should be isolated from the house for 2 reasons. First you should have drywall up without holes or seams as a fire resistant barrier. I’m not sure the the fire rating is, but it is better than exposed floor joists in the ceiling. Second you need protection from CO. With a car running in the garage, you don’t want exhaust getting into the living spaces of the house.
Recently I’ve seen insulation companies using a polyurethane spray foam (Walltite?) that is sprayed like a paint but foams up to fill the space and acts as a vapour barrier as well. I have no idea on the cost. It would seem to me to be the best of all worlds (except maybe cost). That said, I suppose anything would be better than what you have…
The joists look like two by eights, 16 inches on center. As far as the age of the house, it was built in 1931, so I don’t think I’m going to have much luck in tracking down the builder.
Thanks for the assists. With your help, I think I’ve got a handle on this, and I shall only return to the thread if I screw things up… but I’m not sure how I could possibly mess this up badly (excepting, of course, my poor skill in hanging drywall).
I, also, am not a contactor, but I read stuff. If your kitchen is directly above the garage, and there is not a double-layer of drywall to act as a fire retardant, this needs to be remedied ASAP. The seams don’t have to be professionally taped and smoothed, a lot of garages have this brown type of drywall (I guess it’s an exterior grade or smoething) and people never even bother to paint over it or anything. If you have exposed ceiling joists, drywall will certainly not make it look any worse.
