Garage ceiling insulation over drywall?

[GirlnAgarage]

Chatted with my neighbor today. He was loading his cooler to go fishing. I was spackling screw heads. Up and down the street well all have the same floor plans for our houses since it was the same builder. Big front room, nice back den, garage, and all bedrooms upstairs with the master being over the garage. I mentioned wanting insulation above the garage because of the temp fluctuations. He has the same problem and he said our other neighbor had installed some of the foam board insulation right to the ceiling drywall. Is there any problem doing that instead of pulling drywall down, installing insulation and closing it back up?

 

[sstruckguy]

I can't say I have ever heard of that approach.

Assuming, since you said you were "spackling screw heads", that this development is new? If that is the case, I would be on the builder before any other fixes.

 

[GirlnAgarage]

I can't say I have ever heard of that approach.

Assuming, since you said you were "spackling screw heads", that this development is new? If that is the case, I would be on the builder before any other fixes.

Oh no, not new. Our house was built in '85. I'm just working in my garage now.

 

[sstruckguy]

Well in that case, I would back some screws out and go for the "proper" technique

 

[GirlnAgarage]

Well in that case, I would back some screws out and go for the "proper" technique

Yeah...no screws in this drywall, only nails.

 

[Cryptic1911]

should be fine.. you can get that 1/2 or so foam board stuff with the aluminum foil on one side, and just nail it over the top. It won't be the prettiest thing in the world, but it should help some with the temp fluctuations

 

[70redbee]

I would cut some holes in the drywall and blow the insulation in above the ceiling.The foam board over the drywall will give you limited Rvalue and will not help a lot with the temp fluctuations. Just patch the holes when done and paint. This is the best looking and helpful way to get what you want.

 

[srmofo]

Id cut a hole and blow in. It will probably be cheaper.

 

[TimGrz]

In a past house we had vaulted ceilings that had terrible insulation value. We mounted 2x4's, flat, on the ceiling running the opposite direction as the existing structure 24" apart. We then installed 1.5" styrofoam type insulation between the 2x4's. Then dry walled over them.

It worked quite well, and was the only area of the roof that would allow snow to accumulate, and because there was only a 2" "loss" you couldn't tell it was different from the other rooms with vaulted ceilings.

On the other hand, if we could have pulled down the existing plasterboard easily and re-insulated, we would have. It just would have been way to much work and to dirty in a house being lived in. A garage however....

/tg

 

[rieferman]

+1 on cutting holes and blowing in insulation, and then patching the holes.

Also, I believe drywall is considered a "fire barrier" in the garage when there's living space above it, so I wouldn't want a potentially flammable product up there instead (such as exposed insulation) for insurance purposes. But I'm not a code expert, just going by memory.

 

[fefarms]

rieferman is correct. You can't leave foam board exposed. Not only is it flammable, when it does burn it generates toxic smoke, something I wouldn't want below my bedroom.

It also seems substandard, even for 1985, to build a bedroom above an unheated/un-airconditioned garage without insulating the floor of the bedroom. I'm not understanding why the insulation is needed in the garage for these houses, if there is living space above them.

 

[GirlnAgarage]

Thanks guys. Blown insulation is an option I had not thought about. Which is odd because I had been thinking about it for the wall cavity. To blow in insulation I would need to cut a hole in between each rafter(is that what its called?) as it's probably a cavity and not an open area?

In a past house we had vaulted ceilings that had terrible insulation value. We mounted 2x4's, flat, on the ceiling running the opposite direction as the existing structure 24" apart. We then installed 1.5" styrofoam type insulation between the 2x4's. Then dry walled over them.

It worked quite well, and was the only area of the roof that would allow snow to accumulate, and because there was only a 2" "loss" you couldn't tell it was different from the other rooms with vaulted ceilings.

On the other hand, if we could have pulled down the existing plasterboard easily and re-insulated, we would have. It just would have been way to much work and to dirty in a house being lived in. A garage however....

/tg

Creative solution! And we feel your pain here. Our living area is a vaulted ceiling and we have the same problem. My neighbor did mention using this method like you did here. A couple weeks ago we had insulation blown into our attic by the HVAC guys as it was part of our new system that went in last month. They said they were able to get those in that narrow space about that living area to fill it up, but I'll believe it when I feel it. If it isn't as helpful as we hope your method here would be an option.

+1 on cutting holes and blowing in insulation, and then patching the holes.

Also, I believe drywall is considered a "fire barrier" in the garage when there's living space above it, so I wouldn't want a potentially flammable product up there instead (such as exposed insulation) for insurance purposes. But I'm not a code expert, just going by memory.

You bring up a very important issue. I do weld and do grinding in the garage. While not on the ceiling, probably better to sterilize the area as much as possible from hazards.

 

[justanengineer]

If you blow it in, you might consider using a metal detector to find the wiring/plumbing and consider leaving spaces with it empty for future renovations.

 

[MoonRise]

Exposed foam insulation is a No-No, for fire/safety reasons. As mentioned.

IIRC, it will also break down if left exposed and is exposed to UV (aka sunlight or in your possible case, UV from welding arcs).

Also, you'd have to add some pretty thick pieces of foam board to get a 'decent' R-value. Probably about as thick as the ceiling joist cavity is. Cause most insulation materials are (usually) pretty close in R-value/thickness. No free lunch there.

Do it once and do it right. Pull the drywall, install insulation and vapor barrier, install drywall (with screws!), spackle. Done.

Your bedroom will be cooler/warmer AND quieter with the joist cavities/space between the bedroom and the garage insulated.

IMHO, trying to put blown insulation into the floor/celing joist cavities (garage ceiling joists are the bedroom floor joists in this case) is one of those 'Possible but probably not the best ways to do things' things.

And I am also shaking my head and thinking "WTF!?##$" for a builder -AND- the building codes putting a bedroom over a garage with NO insulation. WTF?

No insulation in the garage walls, I can sort of see that one. But no insulation on ALL the 'exterior' wall/floor/ceiling of the heated/cooled house space? WTF?!?!?

Somehow in 1985 'they' ignored or forgot about insulation? 1920's or 1930's or maybe up to the 40's or 50's, but come on. 1985 and there was no insulation?

 

[GirlnAgarage]

rieferman is correct. You can't leave foam board exposed. Not only is it flammable, when it does burn it generates toxic smoke, something I wouldn't want below my bedroom.

It also seems substandard, even for 1985, to build a bedroom above an unheated/un-airconditioned garage without insulating the floor of the bedroom. I'm not understanding why the insulation is needed in the garage for these houses, if there is living space above them.

Appreciate the thoughts on the flammability (word?) of the foam board. I'll heed that advice. Don't need to burn the garage down, much less the house. As for not understanding insulating the garage, the temps fluctuate in there a whole lot in the day. While it is not heated or AC'd, insulating would keep it more stable. In turn keeping the room above it more stable. From a work mess standpoint working on the garage is easier than the bedroom. Also, the portions of the garage walls that are exterior are not insulated, but the walls that share it with the house interior are insulated. The stupid thing is, the very same walls that are exterior portions on the first floor are exterior walls for the second floor in the master bedroom on all three sides (south, west, north).

If you blow it in, you might consider using a metal detector to find the wiring/plumbing and consider leaving spaces with it empty for future renovations.

Noted. There is pluming up there from the master bath and guest bath. There is evidence of that on the ceiling

Exposed foam insulation is a No-No, for fire/safety reasons. As mentioned.

IIRC, it will also break down if left exposed and is exposed to UV (aka sunlight or in your possible case, UV from welding arcs).

Also, you'd have to add some pretty thick pieces of foam board to get a 'decent' R-value. Probably about as thick as the ceiling joist cavity is. Cause most insulation materials are (usually) pretty close in R-value/thickness. No free lunch there.

Do it once and do it right. Pull the drywall, install insulation and vapor barrier, install drywall (with screws!), spackle. Done.

Your bedroom will be cooler/warmer AND quieter with the joist cavities/space between the bedroom and the garage insulated.

IMHO, trying to put blown insulation into the floor/celing joist cavities (garage ceiling joists are the bedroom floor joists in this case) is one of those 'Possible but probably not the best ways to do things' things.

And I am also shaking my head and thinking "WTF!?##$" for a builder -AND- the building codes putting a bedroom over a garage with NO insulation. WTF?

No insulation in the garage walls, I can sort of see that one. But no insulation on ALL the 'exterior' wall/floor/ceiling of the heated/cooled house space? WTF?!?!?

Somehow in 1985 'they' ignored or forgot about insulation? 1920's or 1930's or maybe up to the 40's or 50's, but come on. 1985 and there was no insulation?

I'm glad you mentioned something. Blown in on the ceiling does seem kinda messy if/when the ceiling drywall is finally pulled down. Am I thinking correctly here?

I know this should be done right. I was just curious if anyone heard about putting foam board on the ceiling like my neighbor did. The condition of the ceiling drywall is not the best. I'd like to pull it off but I'm trying to keep that urge at bay for the meanwhile. I'm just talking through this. I've got to get the garage walls done and the shed built outside. Doing too much at once!




Here's a pic of our setup. I figure it is better thane trying to describe it in writing. The green line in the garage indicates insulated walls in the garage. Blue outline & text is the second story of the house.

The garage temp fluctuates a lot. I work from home and I'm in and out of the garage throughout the day. I have observed and felt those temperature differences in the garage and in the master bedroom, in the winter time and in the summer. I think I might go get some thermometers and put one in each place and show how much these numbers one in one day. In the summer its brutal from the afternoon sun. (I plan to insulate the garage door as the heat just radiates from it). In the winter the north wall of the master bedroom (and my walk in closet) is a fridge. We just had more insulation blown in in the attic over the bedroom so looking forward to seeing how that helps.