Foam Board Insulation in Garage

[r00a005]

I have been thinking about adding a hanging shop heater to my garage (about 1000 SF), but it would seem prudent to first think about insulation so I can assess total cost. Right now there is no insulation. The walls are OSB with wooden siding. The garage has about 2 car bays with a "flat" trusses, with one bay having sloping trusses to accommodate a car lift. I was thinking about laying 4x8 sheets of foam insulation on bottom portion of the trusses, and at least the tops of walls. Its pole type construction so the walls are fairly easy to do. I also have fans that can direct heat downward. I am located in PA outside of Philadelphia.

I see 4 x 8 sheets at the local stores to have R values of 10 or 7.7 at the most.

Will doing this provide any significant benefit, or is the R-value too low ?
Thanks
Bruce

 

[b-boy]

It can't hurt, but IMHO you need to go bigger. Foam board on the walls might be sufficient.

Will this shop be heated continuously? If so, I'd look at a minimum of R40 in the ceiling. You can always add batt insulation on top of the foam board.

Will the foam board be covered? I'd be hesitant to run a ceiling mounted heater near uncovered foam board.

 

[r00a005]

Will this shop be heated continuously? No If so, I'd look at a minimum of R40 in the ceiling. You can always add batt insulation on top of the foam board. This is a good idea

Will the foam board be covered? I'd be hesitant to run a ceiling mounted heater near uncovered foam board.I have to think about this. Its a good point. Thank you for the reply

 

[Burl]

My shop is 32X30X12, and I just removed the 1" foam board, the kind from Lowes with the silver on one side. Typical 3.5 pink in the trusses and I added 9" last summer, and the foam started to sag, not real bad but I knew it would get worse. I put up 1/2" drywall. If you can, drywall the ceiling and insulate the **** out of it. Best money spent.

 

[stillnostrebor]

I have 2" XPS in my walls continuous with the only bridges being the poles, and 8" batts in the ceiling... in SW Missouri.

This is all covered with either metal or OSB and all corner joints caulked. (2) 8'x8' insulated OHDs and 1 man door. No windows.

By code it is not enough R-value for either the ceiling or walls, but it has performed quite well in use. It is shaded a good portion of the day which adds to the performance.

I looked at it from the perspective of it is a shop and not a living space, and my goal was to temper the space accordingly. I focused on air infiltration and some R-value. I have seen a good return on that plan so far.

 

[r00a005]

Thanks everyone for the comments. I am finding out from the builder to see what weight the ceiling trusses can tolerate (dry wall ceiling & insulation weight vs the foam board weight vs...)

 

[Chetter]

I have been thinking about adding a hanging shop heater to my garage (about 1000 SF), but it would seem prudent to first think about insulation so I can assess total cost. Right now there is no insulation. The walls are OSB with wooden siding. The garage has about 2 car bays with a "flat" trusses, with one bay having sloping trusses to accommodate a car lift. I was thinking about laying 4x8 sheets of foam insulation on bottom portion of the trusses, and at least the tops of walls. Its pole type construction so the walls are fairly easy to do. I also have fans that can direct heat downward. I am located in PA outside of Philadelphia.

I see 4 x 8 sheets at the local stores to have R values of 10 or 7.7 at the most.

Will doing this provide any significant benefit, or is the R-value too low ?
Thanks
Bruce

I used the same foam when I did the ceiling of my garage, I started by stapling heavy plastic sheeting then I put the foam board up gluing them with liquid nails, then I used furring strips screwed to the trusses and they help keep the foam from any sagging and covers the foam board seams. Lastly, I rolled R-38 un-faced insulation in the attic, garage stays nice and warm. I hope to throw some 1/4" osb up and paint white to match the walls. I used foam boards between the purlings before putting up 1/2" osb and painting white. It's been a work in progress since 1996 when I built my garage and continue to make improvements.