Garage Ceiling Insulation

[bassmann77]

So with this unbelievable cold winter, I am going to put heat in the garage for next winter. My issue/question is what are my options for putting in insulation in the ceiling of my garage that is already sheet rocked? Not sure why the builder did that along with rocking the entire garage without insulation, but that can be another topic. I would like to keep the sheet rock up if possible because it is a 10' ceiling and it would be nice not to have to tear it down.

Thanks.

[18 inch Crappie]

You need to put in a trap door with ladder and then blow in the insulation. The ladders sell for about $130 in a 10' size.

[BartmanMN]

What he said. My neighbor did not have insulation behind his sheetrock on the walls as well and he hired a company in the Summer that came out, lifted up a section of siding, drilled a 2.5 inch hole between each stud and blew insulation in each section.

[harvey lee]

You need to put in a trap door with ladder and then blow in the insulation. The ladders sell for about $130 in a 10' size.

Exactly what I have in my garage.

I do not know exactly how much was blown up there but it looks like close to 18 inches, they really laid it in there.

[BoxMN]

You need to put in a trap door with ladder and then blow in the insulation. The ladders sell for about $130 in a 10' size.

That would be the ideal thing, though you really only need a hatch in ceiling to access the attic, and use a normal ladder to get up there. Blow in the insulation, and climb down, replacing the hatch cover - though the hatch cover must be insulated, and you need to build a (styrofoam) border to keep the insulation from falling out the hatch. As mentioned if you do 18" you need 18" hatch "walls" Just some foam and duct tape works to keep it together, and you need a little roof too, like maybe 2" foam that fits into the opening. Pretty easy. We did it to my brothers and even though it is not heated, it is attached and his rarely gets below zero even on cold cold days.

I do have a built in ladder and it works great, but I store things up there. If you aren't storing things you likely would never need to go up there again after insulating, so don't really need it to be built in. I did build a 2" foam enclosure that fits "over" my ladder when closed to help keep heat from flowing out my attic ladder door.

Sorry for the book... I ramble...

[bassmann77]

Thanks guys. Do I have to worry about any vapor barrier?

[Lund79]

bassman77- Glad you asked because I have the same setup for my garage and was wondering what I needed to do get insulated properly. Also wondering about a vapor barrier.

Box- I am curious if you have a photo of the 2" foam enclosure "over" the ladder when closed. I am more of a visual learner and wondering how you did this. Thanks!

[bassmann77]

Lund79- For what I gathered most people state that we should tear down all the sheet rock off the walls, insulate, and put new rock back up. It will be cheaper and be better insulated than renting the machine and punching holes in the sheet rock between all the wall studs. That is what I am going to plan to do this summer. As for the ceiling, I am waiting to hear back on what people recommend for vapor barrier for the ceiling.

[BartmanMN]

My insulation is blown right on top of the sheetrock on the ceiling. I'm not a contractor though, so I can't tell you if that is the correct way or not.

[MNice]

Personally, I wouldn't worry about the vapor barrier for the following reasons.

-garage doors are not that tight, look at the gaps around the doors, they continuously ventilate

-Every time you open & close the door, the space gets ventilated pretty well.

This is just my opinion and is not to be determined as Gospel

[Down Deep]

Use foam.

[Hoey]

Lund79- For what I gathered most people state that we should tear down all the sheet rock off the walls, insulate, and put new rock back up. It will be cheaper and be better insulated than renting the machine and punching holes in the sheet rock between all the wall studs.

[BoxMN]

Lund, I will try to take some pics tomorrow. Basically it is an inverted "box" that goes around the ladder when it is closed, from the top in the attic. Mine has those stoooopid spriings that go above the "floor level" of the attic trusses when it is closed, so I had to make it taller to accomodate. I used pink 2" and used long deck screws (only a couple on each corner) and then used some foil tape to tape the seems. It is pretty sturdy, for what it is, but not like you could stand on it

It fits flush to the frame, on the top of the plywood flooring area. When I open it, I need to lift/push it away, over to the side, and then replace it when I exit and close the stairs. Pretty simple, just a way to keep the draft of warm air rising so fast through all the gaps left in the trap door area. Not sure how much it is helping, but it cant' hurt. Some of those gaps around the trap door are pretty big, and inconsistent when you close it. I am going to try putting some weatherseal foam strips to help seal the door too. Just trying to close those air leaks on the ceiling, where the warm air goes.

Will post some pics, but it is pretty simple, even a caveman like me could do it, haha! (If I recall, the inside dimensions where like 24w x 46L x 10D, or close to that, for the springs to fit without lifting it up when closed... I had to readjust once since I cut twice and it was still too short )

[Archtek]

I would definitely get a poly vapor barrier up there if you intend to heat it all winter; there will be a lot of moisture in the garage and you really don't want condensation in the insulation. While the best way is to get the poly continuous between the sheetrock and the trusses, it sounds like that will be impossible to do without either taking down what you have or adding a second layer of sheetrock with the poly in between. The other option that's a real PIA, especially with trusses, is to lay the poly down from above, push the poly down against the sheetrock, go over the top of the truss bottom chords and cut and seal around all the web members. I had to do something similar once on a historical renovation. Like I said, a real PIA!

The other thing to be careful of is that code requires a fire separation between the house and the garage. If the garage attic is open in any way to the house attic, you have 3 options that I can think of:

1. Extend the garage wall all the way up the underside of the roof sheathing with 5/8" fire rated sheetrock. Then you can do what you want in the garage attic because the ceiling is no longer the fire separation.

2. Put in a fire rated attic access panel/ladder.

3. Patch the ceiling sheetrock back and tape the joints. But that means no access to garage attic without cutting a hole in the sheetrock again. But that may be a good thing anyway; roof trusses are not designed for storage unless specifically requested during truss design.

[311Hemi]

The other thing to be careful of is that code requires a fire separation between the house and the garage. If the garage attic is open in any way to the house attic, you have 3 options that I can think of:

1. Extend the garage wall all the way up the underside of the roof sheathing with 5/8" fire rated sheetrock. Then you can do what you want in the garage attic because the ceiling is no longer the fire separation.

2. Put in a fire rated attic access panel/ladder.

3. Patch the ceiling sheetrock back and tape the joints. But that means no access to garage attic without cutting a hole in the sheetrock again. But that may be a good thing anyway; roof trusses are not designed for storage unless specifically requested during truss design.

Very good points here. The builder most likely sheetrocked the ceiling because it similar in price to sheetrocking the wall going up to the roof to provide that fire barrier. I know that is why they sheetrocked my garage ceiling, although they allowed me to go in and install a vapor barrier prior to the sheet rockers coming in....otherwise they would not have (I could have had it bid extra).

You will need a fire rated attic access pannel/ladder if that's the case. Keep in mind if your trussed are not designed to support storage, a ladder may be useless.

I will be cutting a hole in mine when I go to insulate the ceiling, and will patch it up after I am done.

[Lund79]

Lund, I will try to take some pics tomorrow. Basically it is an inverted "box" that goes around the ladder when it is closed, from the top in the attic. Mine has those stoooopid spriings that go above the "floor level" of the attic trusses when it is closed, so I had to make it taller to accomodate. I used pink 2" and used long deck screws (only a couple on each corner) and then used some foil tape to tape the seems. It is pretty sturdy, for what it is, but not like you could stand on it

It fits flush to the frame, on the top of the plywood flooring area. When I open it, I need to lift/push it away, over to the side, and then replace it when I exit and close the stairs. Pretty simple, just a way to keep the draft of warm air rising so fast through all the gaps left in the trap door area. Not sure how much it is helping, but it cant' hurt. Some of those gaps around the trap door are pretty big, and inconsistent when you close it. I am going to try putting some weatherseal foam strips to help seal the door too. Just trying to close those air leaks on the ceiling, where the warm air goes.

Will post some pics, but it is pretty simple, even a caveman like me could do it, haha! (If I recall, the inside dimensions where like 24w x 46L x 10D, or close to that, for the springs to fit without lifting it up when closed... I had to readjust once since I cut twice and it was still too short )

Thanks! That description helps me. I was thinking it was on the ceciling side and not attic side. Silly me:)

[BehindtheHead]

the easiest way to install a vapor barrier after the sheetrock is up is spray foam. have someone spray 1 to 2 inches to the sheetrock. the problem with that is you will never be able to take the sheetrock down. good, fast, cheap. you cant have all 3.

[Archtek]

Please be aware that not all spray foam products qualify as a vapor barrier. To qualify as a vapor barrier, a material has to have a perm rating of 1.0 or less. Best to check manufacturer's literature before assuming spray foam will give you a vapor barrier. ALSO, check codes before leaving spray foams exposed to an occupied space. It's been a while since I looked at it, but a "thermal barrier" was required over foam because of the toxic gasses produced when it burns. I seem to recall that there were a few exceptions.

[BehindtheHead]

yes you are correct. open cell isnt a vapor barrier at one to two inches. im not aware of a closed cell foam that is not a barrier though. the stuff i spray is a barrier. and you are correct that in a occupied space it would have to be covered with a thermal type paint, sheetrock, or some other fire rated covering. in a attic it does not have to be covered

[reddog]

Just get up there and blow 10-14 inches of cellulose. If your worried about a vapor retarder, simply paint the ceiling with a vapor retarding paint.