insulation

[camaro77]

hello guys getting ready to insulate the garage its 24x24 I am planning the use R13 in the walls not sure what I need in the ceiling. its 2x6 construction on the ceiling I have a attic above the ceiling with a floor so my plan was to insulate and then sheetrock the ceiling since the attic floor is already in place I have already strapped the ceiling. most of the runners are 16 on center I do have a few that are a lot wider apart I have not measured to know exact width tho.

 

[The Cobbler]

R13 in walls is fine, ceiling , if you want to maintain heat in there should be closer to R-50
pay for insulation once, pay for heat every time the furnace cycles
look at blown fiberglass for the ceiling

 

[Firebrick43]

Well, you will only get r19 with Fiberglass batts. As cobbler said you should be around r50 or at least r38 but there is no way to get that with 2x6 depths.

To boot you should not have strapped the ceiling or put in the attic floor?????? You have really limited yourself on installing insulation. Is one or the other screwed down and be removed?

With the 2x6 cavity spray foamed you could reach r30-35 ish but it's going to be difficult to do correctly with strapping and is going to be expensive. You could add 2" of xps foam on top of the attic floor and another 3/4" subfloor on top of that to meet code but again a lot of extra expense.

 

[camaro77]

the floor was already there when I got the house so I have no control over that

 

[Firebrick43]

Ok, maybe I was a little blunt and see that your defensive about it. I am sorry for that.

You don't need to have both the floor and strapping off, just one of them. Can you pull the strapping down?

Also we really need to know what your goal is. If it's just to heat the shop when it's cold out while you occupy it? Or do you intend to heat(even at a low level like 55 degrees) and ac it all year round? If the latter you need to be serious with it. Even if the former you really need to think long term as it will be much more difficult in the future to bring it up to what it needs.

Do you have pictures as your description is lacking in specific terms. It sounds like you have attic trusses but it's vague enough you may have rafters with floor joist but then you have a whole nother can of worms to deal with.

 

[StreetGLi]

Is the attic usable? Are you going to use it? What's the ventilation up there? If it's not suitable for storage ( ie your roof system wasn't designed for loads) and you're not going to use it, can you pull up the floor sheetrock the ceiling and blow in a ton of insulation?

Alternatively if you are going to use it, is it feasible to sprayfroam and insulate the entire space?

Sent from my LG-H873 using Tapatalk

 

[stm317]

Rigid foam panels (preferably polyiso) cut to fit snugly between your framing will give you a bunch more Rvalue than fiberglass. Filling that space with fiberglass will give you R19. Filling it with polyiso would give you something like R30-33, and it will do a much better job of limiting air movement, which also helps with drafts and allows the insulation to work more effectively.

The best option might be closed cell spray foam. It's the same polyiso as the rigid sheets, but when sprayed on, it seals up everything and effectively raises the R value as air movement is completely stopped. But there are drawbacks. Spray foam is very expensive, and requires very skilled professional application. Improper application can cause various issues and make it much less effective. Your average GJer can do the foam panels on their own and get 95% of the benefits of spray foam for way less $$$ and it's harder to screw up. I think it's the best approach for most of our cases.

 

[camaro77]

I do plan to work in the garage I build race cars mostly the ceiling is about 9.5 feet or so not looking to heat it to 75 degrees just looking to be able to keep some heat in the attic I plan to install a attic fan and possible put a shelf or 2 up there for some storage of thing that I would not use very often. just trying to make it better than it is not to sound cheap but I cant spend a lots of money on this. my girl works at lowes so hoping to be able to do this project with supplies from her work. I don't know how to post pictures I could send them to someone thru email or text message tho. thanks guys for the input

 

[camaro77]

Ok, maybe I was a little blunt and see that your defensive about it. I am sorry for that.

FIREBRICK no worries at all I just spent way to much time installing this strapping alone to even want to think about pulling it down. I will know for the next time that I jumped to far ahead story of my life live and learn I guess

 

[Bretny]

Since your attic floor is alreaty in place just use fiberglass batts designed for 2x6..i believe thats r19. Should be fine for a garage.

I also have about the same size garage. 24x24 with r13 in the walls and 2in foam up on the roof rafters. No insulation on the gabel ends all last winter. I kept it about 35* with a 45kbtu propane unit heater that has a standing pilot (not very efficient) i used about 200lbs of propane last winter.