Insulating a finished garage

[jdub63]

My "energy efficient" home doesn't have any insulation on the exterior walls of the garage. However, the attached common wall is well insulated. In order to reduce the heat buildup in the garage I was looking for options on insulating the existing walls.

Here's my current options as I see them:

1. remove the drywall and install batt insulation
2. drill small holes and use slow rise foam
3. cut large holes and use blown cell or fiberglass
4. do nothing

I still plan on around 18 inches of blown in the attic above the garage.

Thoughts / ideas?

jdub

 

[fury9]

remove drywall, install r-15

 

[Choptopjimmy]

^^^^^ what he said.

 

[Nicholas]

Add a solar powered exhaust fan on the roof to **** out the heat.

 

[noslocars]

I pulled all my drywall down and insulated it with r 15. It also gives you the opportunity to run any wiring you want to add at the same time. I was actually able to reuse my drywall. It just took some extra mud when finishing it.

 

[jdub63]

thanks for your inputs....

 

[NUTTSGT]

I pulled all my drywall down and insulated it with r 15. It also gives you the opportunity to run any wiring you want to add at the same time. I was actually able to reuse my drywall. It just took some extra mud when finishing it.

That would probably be my suggestion but I doubt I would reuse the drywall unless I could easily get to the screws.

 

[Kevin54]

I wouldn't mess around with reusing drywall as cheap as it is. Rip it down, insulate properly, then put new drywall up and finish. As far as insulation goes, it's up to you. Batt insulation will work fine. I'd buy up a few cans of insulation foam though and seal around corners and windows before tossing up the new drywall.

 

[noslocars]

I guess if it's fully finished I would just buy new drywall but if it's just taped, It should come off pretty easy. Mine did and the (19) 10 foot panels I reused saved me some coin. I think it turned out alright.

 

[JimVonBaden]

Off topic a bit, considering I have a detached garage, and it is fully drywalled, how much benifit do I actually get from insulating the walls versus just the ceiling?

Jim

 

[Falcon67]

Off topic a bit, considering I have a detached garage, and it is fully drywalled, how much benifit do I actually get from insulating the walls versus just the ceiling?

Jim

I'll say - a lot. My west wall runs 130F~150F in the summer and the inside of the wall is 90F. That's HardiPanel, R-13, then 7/16" OSB

 

[Kevin54]

Off topic a bit, considering I have a detached garage, and it is fully drywalled, how much benifit do I actually get from insulating the walls versus just the ceiling?

Jim

Are you serious? You built the garage and never insulated and you're in Pennsylvania? If it's not insulated and you're trying to heat it, you're just tossing money away. Same with it in the hot summer months. It will be 10-15 degrees cooler in the garage by not having the sun heating things up inside. When I'm in the garage, I warm it up to around 68 degrees. When I shut things down, I can go out the next day and it will still be 55 degrees in there. That's with just 2x4 walls R13 and R30 in the attic. And our nights have been getting down in the low to mid 20's.

 

[NUTTSGT]

Off topic a bit, considering I have a detached garage, and it is fully drywalled, how much benifit do I actually get from insulating the walls versus just the ceiling?

Jim

Aw man, you didn't do the walls ? Tell me you're kidding Jim.

 

[JimVonBaden]

Are you serious? You built the garage and never insulated and you're in Pennsylvania? If it's not insulated and you're trying to heat it, you're just tossing money away. Same with it in the hot summer months. It will be 10-15 degrees cooler in the garage by not having the sun heating things up inside. When I'm in the garage, I warm it up to around 68 degrees. When I shut things down, I can go out the next day and it will still be 55 degrees in there. That's with just 2x4 walls R13 and R30 in the attic. And our nights have been getting down in the low to mid 20's.

Alexandria, VA, 4 miles from DC.

My house was built without my input, so yes, no insulation in the garage, though they added drywall.

The drywall looks good, and to be honest, for winter it is OK with my oil filled electric heater. But for summer it is fuggin HOT! I can get to the ceiling to blow in or lay insulation, but the walls would mean a LOT of work. So, I am wondering how much benifit I would get from just the ceiling?

Jim

 

[Grumpy365]

Honestly,

Wall insulation isn't where your load comes from, it comes from the ceiling?

If I was doing construction, I would do it, ,but the gain isn't worth the pain to do it now.

 

[NUTTSGT]

Alexandria, VA, 4 miles from DC.

My house was built without my input, so yes, no insulation in the garage, though they added drywall.

The drywall looks good, and to be honest, for winter it is OK with my oil filled electric heater. But for summer it is fuggin HOT! I can get to the ceiling to blow in or lay insulation, but the walls would mean a LOT of work. So, I am wondering how much benifit I would get from just the ceiling?

Jim

Jim, if you want the walls insulated, I'd suggest drilling a hole with a holesaw of appropriate size and blow insulation in the wall cavity. Once you are done, it'll take a little drywall work and paint to make it look good again. Just remember on your back wall to get below the top plate as I know you have a "mini-vaulted" ceiling.

 

[fury9]

I wouldn't do that, Unless you drill a hoke in the top and bottom,and who;s to say you're getting past all the obstructions in the wall? Rip it out, insulate, have no second thoughts

 

[Herb67SS]

Jim,
If its our lovely summer temps you are trying to tame, consider a thru wall venting fan at the peak of gable end wall of the garage on a thermostat or switched outlet.

Blowing or foaming in the stud bays is possible. I wouldn't re-drywall an entire garage just for that. I'd Call Vick at Southland Insulation in Manassass and discuss with him. Best and most reasonable outfit around this area. Tell him Herb referred him. They just did an EXCELLENT job on my entire 28x36 for a very reasonable price.
/h

 

[Kevin54]

Alexandria, VA, 4 miles from DC.

My house was built without my input, so yes, no insulation in the garage, though they added drywall.

The drywall looks good, and to be honest, for winter it is OK with my oil filled electric heater. But for summer it is fuggin HOT! I can get to the ceiling to blow in or lay insulation, but the walls would mean a LOT of work. So, I am wondering how much benifit I would get from just the ceiling?

Jim

Where the hell did I get Pa. from

As far as just insulating the ceiling, you'd gain a lot from it. For one, it would keep your heat from going through in the winter and coming through in the summer. If you just happen to store anything up there, I'd recommend batts instead of blown in. If you do decide to use blown in insulation, check to see what it cost to have it done vs. DIY. If the cost is minimal to have it done, it would be well worth it. I added blown in to our house, maybe 10 years ago and it's a hell of a messy dirty job. Plus the dust gets everywhere. By the time you buy it, haul it, take a chance on the blower working or not, taking the blower back and swapping it out if it doesn't work, it's worth it to have someone else do it.

My wife and I put R30 batts in my garage which is 28' x 36' and we had it done in 2 hrs. which we stopped a couple of times to have a break. Way cleaner and easier.

 

[Kevin54]

I wouldn't do that, Unless you drill a hoke in the top and bottom,and who;s to say you're getting past all the obstructions in the wall? Rip it out, insulate, have no second thoughts

I don't think JVB is going to rip out his drywall. One could always put a hole at the top and bottom and cover it with trim.

 

[Rockuf8]

My "energy efficient" home doesn't have any insulation on the exterior walls of the garage. However, the attached common wall is well insulated. In order to reduce the heat buildup in the garage I was looking for options on insulating the existing walls.

Here's my current options as I see them:

1. remove the drywall and install batt insulation
2. drill small holes and use slow rise foam
3. cut large holes and use blown cell or fiberglass
4. do nothing

I still plan on around 18 inches of blown in the attic above the garage.

Thoughts / ideas?

jdub

I had the same dilemma, and went with #1, and not looking back.

remove drywall, install r-15

Why r-15? I'm using r-13, the r-15 wasn't available at my HD and the difference is negligible, it only seems to come in bags, and I decided against bags since there would be too much waste with 7'8" cavities, didn't want to piece and tape small pieces together either.

I pulled all my drywall down and insulated it with r 15. It also gives you the opportunity to run any wiring you want to add at the same time. I was actually able to reuse my drywall. It just took some extra mud when finishing it.

I was able to reuse mine because it was simply screwed in and never taped, or spackled. It would be hard as hell to get full pieces intact if they're finished.

It will be 10-15 degrees cooler in the garage by not having the sun heating things up inside. When I'm in the garage, I warm it up to around 68 degrees. When I shut things down, I can go out the next day and it will still be 55 degrees in there. That's with just 2x4 walls R13 and R30 in the attic. And our nights have been getting down in the low to mid 20's.

That's what I like to hear, even if the garage was kept at 45-50 in the winter w/o any heat I would be more than happy.

 

[NUTTSGT]

I wouldn't do that, Unless you drill a hoke in the top and bottom,and who;s to say you're getting past all the obstructions in the wall? Rip it out, insulate, have no second thoughts

While ripping it out the drywall would be st the absolute best way to get everything insulated, it's generally consider impractical for somebody that already has a nice finished walls and garage.

If he has no insulation at all, it'll be better than what he has right now. Sometimes, you take what you can get and be happy with it.

 

[toolmiser]

If you were worried about "proper" coverage when blowing in the insulation into the walls, why not rent a thermal imaging camera and be there when they do it. Then if you need a few more holes, go for it.

 

[JimVonBaden]

Since I have totally hijacked the OP's thread, I might as well show you the structure of the building:

Ceiling above the drywall:

Walls:

Semi-finished:

Done:

So, you can see why I am reluctant to rip out the drywall. I could insulate the top 3/4 of the walls with blow-in, but it would be messy. I might just do the ceiling I do not plan to store anything there, but will have an opening).

Jim

 

[darkk]

If you have vinyl siding, an insulation company can just pull the bottom lip out on the siding at the top and in the middle of every stud location from the outside. Blow insulation in and just tuck the lip back in. Blown in insulation has a higher R value than standard batting. You won't even know they were there.

 

[2Big2Ride]

JDub - just a little northeast of you and had the same situation. Our garage door faces east, uninsulated garage wall with two windows on the south side. I insulated the metal sectional garage door, laid down bats in the attic, and sun screen on the two windows. That was enough of a difference I don't see a need to rip down the drywall to insulate the south wall. You might try your garage in steps and save the uninsulated wall for last - might be enough difference you won't need to do the wall.

 

[yhprum]

What about some thermal insulating paint? I havent used this before but have wanted to. http://www.hytechdistributors.com/
This just one brand. Could put it on the exterior walls that see the sun. Maybe the garage door to cut down on radiated heat.
There are a lot of threads if you google DIY Lizard Skin, which is a similar car based product. Basically it is latex house paint with microspheres mixed.

 

[OccupantRJ]

Just for reference if this helps anyone. My shop has vinyl siding, tarpaper, and OSB exterior, with R13 paper faced insulation inside, with 1/2" plywood walls. The ceiling is wide open to the roof at the moment. When it is 20 degrees here, my shop temp is at 40. When the temp is at 30, the shop is at 50. This is with wall insulation only, and no heat whatsoever. I will be adding metal ceiling this spring, and expect it to end up pretty comfortable after adding r19 or more in the attic. I am in the process of installing a 2.5 ton heat pump for AC and heat.