insulating a cement garage ceiling

[Tom7227]

I have a spancrete ceiling in my garage. I'd like to be able to heat the garage for occasional projects. It only has 7 feet of clearance so space is critical. Someone recommended Thermax as it meets fire code. is this correct? How thick - the 1 1/2 inch pieces are twice as much as the 1 inch $28 vs $13.79. I've had a large woodburner going for a couple of days and you can't get the place warmed up because the cement is so cold. In the long run I may put in a gas furnace - should that be a consideration on how much to put in?

[sparcebag]

If it were me I'd install furring strip 3/4 inch then install 1/2 inch foil backed insulation.between the air space 3/4 inch and the rigid insulation rated R3.3 most the heat will not get through,Also I use a small fan pointed at the stove pipe towards the ceiling to circulate heat.

I have the propane wall furnace in the garage and woodstove,propane is initial heat till wood get goin.

[Nutty Fisherman]

Have you thought of spraying it with foam insulation?

[Tom7227]

The foam would be ideal but I've been told it would run over a grand. It's 23 X 33. If I go with the 1 inch thermax I can get it done for maybe a little over $500 depending on the fasteners I have to use. It has been suggested that I put 1 X 2 or similar across at the ends and middle and attach it to the ceiling with those cement screws and washers. The spancrete is really tough to drill so I'm thinking about using the 7mm rem mag for that part.

[King Canada]

Whats above the concrete?

[Tom7227]

A deck is the top of the garage. It has pavers on it - no way to solve the problem from the top.

[sparcebag]

Get a cheap .22cal pin gun use some PL 200-400 glue and shoot pins through the furstrips to attach them.then go to my first post,you dont need much insulation,just stop the spancrete from absorbing all the heat.

Have you tried your woodstove with a fan the way the garage is now to just circulate heat?

[Tom7227]

Sparc,

I have one of those guns and it is very irregular when trying to put stuff into this ceiling. Sometimes it goes through the furring, sometimes it doesn't go in all the way. I have a thermostatically controlled fan on the wood stove and have also had a 20 inch fan blowing on it. The stove is huge - I used to heat my old house with it, but nothing seems to be able to keep ahead of the heat loss in the garage. The garage is attached so one wall is warm from the basement heat. The back wall is about 2/3 under ground. I don't know whether the two outside block walls would have to be insulated as well.

Tom

[sparcebag]

Sounds strange? My garage is framed no insulation in the walls,ceiling is heavyly insulated,I use a woodstove no jacket with no blower just Vogelzang box stove.I work in just a teeshirt in zero weather.I also had it in a walkout basement no ceiling insulation and kept it at least 55 degrees it was 26X32 ft.

Ya got a damper or two on the pipe? I just cant see that much heat loss unless the stove isnt working properly.

Also your pin/nail gun can be used with different loads,I think purple brown being heaviest and yellows least power,

Tapcon screws arent that hard with a hammer drill 3/16s concrete bit and a corded drill motor with a phillips bit.I believe if ya buy a box of tapcons a bit comes with them,For just lightweight rigid one Tapcon every 4 ft oughta do with PL in the field.

[Drew]

I would guess that when the pin goes through the furring you are hitting a core in the span crete. Try finding where the solid part of the individual panels are and fasten the fur strips there. would have more faith in tap cons over the pins. Could also use a 1/8 bit, drill a hole though the fur strip into the solid part of the span crete inseart a piece (or two) of tie wire and than use a 16d nail. Solid as a rock. 3/16 drill bits last a bit longer but you will have to use a few more pieces of wire.

[11-87]

Someone recommended Thermax as it meets fire code. is this correct? How thick - the 1 1/2 inch pieces are twice as much as the 1 inch $28 vs $13.79. quote]

I would bet that the 1" price isn't THERMAX.. 1" Thermax should be about $20.00 a sheet. For $13.00 I bet that is plain old Celotex/TuffR. Check for Sure because the that will burn fast. Thermax would Smoulder.

I had a scrap of Thermax and it didn't burn very easy. It has some Fiberglass in it. I think the other is just plain old POLY-ISO