I need to insulate my attached garage. Right now, it's just studs. Plan is to insulate and put up some plywood and/or plywood and wallboard. One wall of the garage faces the outside, while two walls face the house. I've been told it really makes a difference which way the foil-side of the insulation faces, depending on whether it's an exterior wall or a wall facing a space that is normally heated. Apparently the foil can trap moisture if there is a heat gradient, thereby setting up the proper conditions for mold growth. What's the standard on this? I tried asking at the big box store and got a confused look. While we're at it: Is there any value to putting a thin sheet of plywood up first, and then plaster board, or something similar? I eventually want to hang some cabinets, shelves and garden tools. I've been told the plywood will add some strength and material to drill into, but I've also been told it's utterly unnecessary. Thanks
Foil is a vapor barrior, vapor barrier ALWAYS faces the living area. That being said, unfaced insulation is acceptable in a garage.
When you do this, you should Green board the lower half of the wall, (water resistant) then fur out the upper half, and peg board it. Then you can hang all kinds of stuff on the pegboard. If you wire it well ( and you should for the future) and hang lights, paint it gloss white, you have a great shop or man cave!
I wouldn't put up plywood unless thats your finished covering. just go with whatever you want your finish to be, whether it be plywood, drywall or osb. there isn't a need for an extra layer of plywood since you want your cabniet and hook srews to go into a stud anyways.
No, unless you need the strength of the plywood as a shear ply. Earthquakes and tornadoes might call for that. Wood isn't a good insulator. Since you still have sticks showing, you might look into spray Poly-U foam by a contractor. Pretty efficient but more $. You have to be the one to make the decision on the cost benefits to R value benefit.
The common walls with the house will already be insulated, per building code. I would not insulate the common walls with the house, unless you are trying to limit noise transmission. By insulating the rest of the garage, you will be adding insulation to those walls of the house. At the same time, by not insulating the common walls, heat that escapes through the house walls will add to the ambient temp of the garage in the winter time. It is not uncommon, out here, to have the garage stay around 40 degrees during the winter with this set-up.
I did my whole garage in OSB (Oriented Strand Board, sort of a poor-man's plywood). This meant I could screw in hooks or attach pegboard anywhere I wanted without having to care about where the studs were. It also meant I could bang the walls with bikes, wheel barrows, shovels, you name it, and not have holes punched in the walls. Almost. The foil goes on the moist, warm side, which in the US is almost always the living area. If you live somewhere extremely hot and humid and air condition heavily, then you might want to switch it around -- but you'll probably be dealing with all kinds of other weirdness anyway. +1 for wiring it up well first. Personally I wouldn't use any kind of sheetrock, normal or Green board, I'd go with plywood or OSB. Pegboard is good, too. I heard that if you paint it slightly yellow instead of harsh white, it will feel warmer on cold winter days. Unfortunately I'm not so good at choosing colors, with the result being that there is a house in Homestead with a nearly-canary-yellow garage.
Yes, I'm going to layout the electrics first. In fact, my electrician also does some GC work, so I may have him bang it all out at once. If I can save a buck and some time, I've been thinking about dropping the insulation on my own. The walls were originally sheetrock (I think in the 50s they called it cement or concrete board). I had to demo it because the previous owner ran the electrics on the outside of the wall, rather than behind the wall. There were wires and cables strewn all over the walls, some only 4 or 5 feet up, which I couldn't live with aesthetically and from a safety point with two small kids. I'll almost certainly hire someone to do this because my layout skills suck; for example, ability to place the holes for the outlets etc..I know I'll make a mess out of it. For a few hundred bucks, someone with experience will wrap it up in about 3 hours, whereas it would take me 3 weekends.I just want to be educated before starting so I don't have someone tell me what I should do, without understanding.
Gypsum wall board is an excellent fire stop. Plywood and OSB, not so much. Something to consider. I would think there may be building code to apply in this situation too. This may or may not be a big concern for you, but perhaps someone here know what is typically okay for an attached garage finish. I like the idea of OSB, but I would still put sheet rock over it. Eric
Just finishing a kitchen remodel with 2x4 exterior walls. Removed the 1974 R11 fiberglass batts and had medium density closed cell foam blown in. Got R21 in the same space as we had R11 before. Works for me but my area wasn't that big. Where I live in Colorado it will pay for itself in < 10 years. May not work for you. Tom
Insurance company's can get nervous about plywood and/or osb in a garage. That is one of the reasons many times there are 2 layers between garage and living space.
Yeah I am not sure about NY but up here in MA you need two layers of 5/8 sheetrock anywhere a garage meets the house. You will also need a fire rated door IIRC.
Mildew and mold resistant building materials would be the best option. I am a HUGE FAN of the blown in foam. It insulates. Plus it seals all the little nooks, crannys and electrical plug ins where the cold air roars through. Plus it does not settle, retain moisture, or mildew an mold.
Me too except that it's a bit pricey. I need to insulate my crawl space and exposed foundation and have looked at this supplier.
Try looking at Tiger Spray foam (do it yourself). No vapour barrier to buy. Adds structural rigidity to walls. You need to sheetrock it though. Burns like a mutha. I guess it doesn't burn like it used to "We are the ONLY supplier offering E-84 Fire Rating STANDARD in our surface spray product line."
I looked into spray foam, But you have to take they're word for what R value you're getting. Half pound is considered open cell and as you get up to around 1 1/2 pound it becomes closed cell and acys as its own vapor barrier. I went with polyisocyannurate (sp/) It has and R value of 7 per inch. "styrofoam" is I think Dow corning's product and is extruded polysyrene and is R 6 per inch. The white crubley stuff is expanded polystyrene and I forget its R value , but is less than both. It was alot of work, but i Cut the rigid foam boards to fit loosely in the joist and stud bays and " caulked" them in with the cans of spray foam from the box stores. I think I have the best possible insulation you can get this way. I'm not sure if they claim to be able to get more than R 7 per inch with the sprayed in stuff. But I dont think so. And you'ld have to foind an honest guy.
Sorry, some pics of my radient heat I thought was insulation shots . Sucks being blind. But anyway, I cut the boards on the bandsaw. I had to do two layers in the walls and floor. 6to7" in the floor and 5 1/4" in the wall. I figure at least R 35 in the walls. One thing to remember is the R value they give fiberglass is in a lab under the best possible scenario. Few people actually achieve that in real life. Lots of gaps around outlet boxes and such. I was lucky enough to get a good deal on the polyiso boards from a guy on craigs list. So I guess that has alot to do with deciding to go with spray foam thats done in two days and my way that took 6 months .....But I saved alot of money and I still think its better than the sprayfoam. YMMV..
I would certainly agree that you need a good firestop between the garage and living space. In my garage, the walls remaining to be finished were all exterior walls, so there wasn't any issue of fire going through them to living space, so I wasn't thinking in terms of fire stops. Would having sheetrock on those exterior walls be of any benefit?
My buddy used rigid foam then used spray foam overtop to seal and add extra insulation. Rigid fills up the space and is cheaper. I might use this on some retrofits. I liked the pics. Always cool to see how people do things. Wondering what your reflective material is? Did you look into Warmboard? My friend used it but it was expensive. Saves on labour though.
