How can we better insulate our garage to keep the heat inside our house?
January 24, 2014 4:52 PM   Subscribe

With all the cold weather we've been having, the bedroom above our single car garage has been positively chilly. The rest of the house is nice and toasty, but that one room is several degrees cooler than anywhere else in the house. How can we make it better?

Just about every other vent in the house is closed but the ones two our three bedrooms and while the other two are quite lovely, this one room (and it is a big one) is downright chilly. We suspect it is simply because it is above our single car garage. We're thinking about doing something about it, if possible.

Would getting better insulation installed in the ceiling of the garage help the problem? If so, is this kind of renovation worthwhile (not from a resale value)? I imagine if it is effective it would have benefits in the summertime, as well, when we want to keep the heat out of that room. Will it affect our heating bill much?

The garage itself is quite cold. The door is pretty thin. This is a newer build house and the garage door, I imagine, is not that great at keeping the heat out on its own. With that said, the interior of the house beside the garage is fine. It's just this one room above it.

How much is a reasonable price for this kind of thing? We're not handy people at all and so we'd probably need somebody to not only tear down the finished ceiling in the garage but put it back up again after the insulation is in. And who would we call? General contractor, or just an insulation guy? Or something else?

Thanks. As first time homeowners we don't know a lot about this stuff.
posted by synecdoche to Home & Garden (13 answers total) 4 users marked this as a favorite
Does the bedroom above the garage have more outside walls than the other rooms? Or a different roof structure. You do lose some heat through the floor, but outside walls make a lot of difference.
posted by anadem at 5:00 PM on January 24, 2014

Response by poster: Same roof structure. Probably more wall surface area, but all of the bedrooms each have two outside walls.
posted by synecdoche at 5:08 PM on January 24, 2014

I would get spray insulation on the ceiling of the garage. Not only does it insulate, it also fills any spaces where exhaust may enter the above bedroom.
posted by sanka at 5:12 PM on January 24, 2014 [2 favorites]

The garage door is probably the first thing I would upgrade: anything else that isn't just isolating that room is going to be less effective.
posted by LucretiusJones at 5:17 PM on January 24, 2014 [1 favorite]

I don't live in a very cold climate, but I did just have insulation installed below the floor and in the ceiling of my house (none in the walls) and it has made a dramatic improvement in both comfort and heating bills. I think insulating the garage ceiling would make a noticeable difference in your case. Most people don't realize how much heat can leak out of an uninsulated floor.

I wouldn't try to do things to make the garage appreciably warmer; that won't be a good investment. Concentrating on insulating living areas from the garage does make sense. You may also be able to get a rebate from your utility.
posted by quince at 5:52 PM on January 24, 2014

Having a cold floor but warm room is worse than the opposite, so even if the room stays a little chilly, but you can warm up the floor, it'll be fine. Insulate the heck out of the garage ceiling and also look at installing in-floor radiant heating.

Second, kill any drafts.

After that, your options are simply to bulk up insulation everywhere or increase heat input. But the first two tasks above will probably be enough if the room is similar to the rest of the house, and the rest of the house doesn't have any issues.
posted by flimflam at 6:16 PM on January 24, 2014

Does the garage have a finished ceiling already? Styrofoam is a very good insulator. Also, obviously very cheap, light, and easy to cut. You might want to nail some Styrofoam sheets to the garage ceiling until it gets warmer out. If anything on your garage ceiling runs hot (a hot water pipe, for example) I'd put something that isn't flammable between the Styrofoam and that hot spot, though (maybe some lighting egg crate diffuser) -- Styrofoam is used as insulation in construction, it isn't dangerous to put up there, but just to be on the safe side.

Do the cold bedroom and garage have windows? You can use cling wrap to insulate the windows. You pretty much just tape it in place. If you have a ladder or can reach the exterior of your windows, you might want to take off the window screen, tape it to the outside of the window, and then put the screen back in place to hold it. I think that gives a better seal than just taping it to the window from the inside. Though either way, the cling wrap actually helps *a lot.*

You can put draft stoppers at the door and windowsills. There are a ton of DIY tutorials online if you don't already have some (the tutorials all basically come down to filling a cloth tube/sock/tie with sand or rice and fastening it shut, no real DIY required). For the garage door, depending on how your particular door looks/works, you might be able to cut pipe insulation (which is basically a Styrofoam tube) and stick it onto the end of that door, too.

Thermal curtains. Also helps *a lot.* Again, if you have a window in the garage, it might work to get a thermal curtain for that window, too.

Floor coverings make a huge difference in insulation, and they don't have to be permanent. For the garage, a floor covering could be anything from a length of laminate flooring/tile to foam tiles to cork tiles -- whatever's insulating and flat enough to drive over. (I assume the garage floor is just concrete, and I bet a lot of heat seeps out of the garage through that floor). For the bedroom, if it's already carpeted, I'd pick up some rag rugs from a craft store or a cheap big box store like Kmart. If it's not carpeted, now is the time to get a big rug or two (and maybe some rag rugs to put on top, if you like that look and/or it still seems cold).

And always keep the closet doors closed. If the garage has open shelving, I'd look to replace that with (plastic) storage cabinets instead, because they'll work a lot better to insulate.
posted by rue72 at 6:36 PM on January 24, 2014 [1 favorite]

Closed-cell spray foam is a good idea. You'll want to make sure you're working with a trained and experienced foam contractor, because applying these foams correctly is fairly tricky. You'll want to use someone who's been in the business for a while and that has good references. I'd suggest doing the interior walls of the garage in addition to the ceiling, so as to seal off the garage from the rest of the house. This will help ensure exhaust fumes and other noxious chemicals don't get inside the living space. This video shows a garage that has been well isolated from the rest of the house, using spray foam and some extras.
posted by Monday, stony Monday at 8:21 PM on January 24, 2014

As for your heating bill, it should enable you to save a bit, but it will depend on how the rest of the house and the walls and ceiling of the room are insulated. But I think it's worthwhile for comfort and air quality reasons.
posted by Monday, stony Monday at 8:31 PM on January 24, 2014

Check with your power company for energy saving initiatives. Mine had a list of approved contractors to come look at the house and recommend what to do for free. Then the power company paid over half the cost to add insulation to my house.
posted by ctmf at 11:09 PM on January 24, 2014

Holmes on Homes has done several stories about cold rooms over garages. The solution can involve removing the garage ceiling and super-insulating the floor above. It also may involve sealing ductwork or even moving ducts. One thing he did not do was simply cover the garage ceiling with insulation, especially styrofoam (it is flammable).
posted by Gungho at 5:45 AM on January 25, 2014

For some keywords that may help, what you want to look at is where the boundaries are (or what your envelope is) of conditioned space. Like commenters said above, adding a garage to your conditioned space is a good way to spend a lot, both in insulation and increased heating costs (from increasing the volume of air you're heating).

The most cost-effective strategy is to eliminate drafts and air infiltration from non-conditioned to conditioned space, mostly because it's typically cheap. Wrapping windows, using caulk (or tape in some cases), draft stoppers, etc, are all low-cost ways to avoid getting cold air in your warm air. Secondarily, upping the insulation on the boundary will also not cost too much but will pay off a lot.

Spray foam, which was recommended above, is often recommended because it will both air-seal and insulate. You can do this commercially for large spaces or with the cans of Great Stuf along gaps and seams.
posted by bookdragoness at 6:34 AM on January 25, 2014

Yes, you probably want to insulate (depending on what is there now: floor, walls, ceiling) and you probably want to do some air sealing (bonus rooms like yours are often poorly air sealed to the space below and at the junction between the house proper and the bonus room). Don't insulate the garage itself as it should not be a heated space (you insulate and air seal between the bonus room and the garage).

First though, spend a small amount ($100-$300, there are often rebates from government or utilities to help with this) to get an energy assessment of your home done. Ask the inspector about the bonus room issue specifically and get his/her recommendations to move forward.

To do this right, you are likely to spend thousands of dollars so it makes sense to spend a little bit before that to make sure you are taking the most effective steps to save energy. You'll also get to see other areas that you might be able to save energy in your home. The internet can't substitute for someone who can poke around in your house and do air leakage testing, etc.

Please don't just start nailing up styrofoam and installing floor coverings.
posted by ssg at 6:27 PM on January 27, 2014

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