Insulating an unfinished garage

TJMS81 · 01-23-2011, 12:52 AM

I have an unfinished garage that desperately needs some insulation. Not fun to work in a garage when it's 15 below outside. My trouble is this, I am trying to save on cost and was hoping to get the unfaced roll. BUT, those are 15" wide and the trusses are spaced 24". Since I use the rafters for storage, I am wanting to put the insulation in between the trusses right up next to the roof. The 24" batts are 3-4 times the price and could make the project unaffordable. Once the roof is done to hold some heat, I'm want to start doing the walls. That will be fun because the previous owner used peg board for every wall. Nice and convenient storage yes, but a pain to take down and put back up.

We live in western WY at 7000' so I'm not sure why it wasn't insulated when the garage was added on in the first place.

Any suggestions?

benjamincall · 01-23-2011, 01:47 AM

Around here I see 3" polyiso foam on Craigslist for next to nothing. I believe I've seen salvaged foam for 3 dollars a 4x8 panel. I found a bunch of people selling some in your general area, so let me know if you'd like me to help you track some down.

TJMS81 · 01-23-2011, 11:06 AM

I've never used foam board before. Is there any issues with condensation or other moisture problems? I don't want my garage roof to rot behind the insulation. What about fire considerations? Otherwise, sounds like an very good option that I had not considered.

benjamincall · 01-25-2011, 10:11 PM

Quote:

Originally Posted by TJMS81

I've never used foam board before. Is there any issues with condensation or other moisture problems? I don't want my garage roof to rot behind the insulation. What about fire considerations? Otherwise, sounds like an very good option that I had not considered.

I see a lot of conflicting reccommendations on how to secure the foam. Maybe someone else could chime in on that concern.

benjamincall · 01-25-2011, 11:46 PM

Quote:

Originally Posted by philmeup

I have a tri- level home,with a heated wall up against a un- insulated garage I now have a leak in my living space,it is 5F here today,and tons of snow on the garage roof,I am thinking that it is a ice build up,under the shingles ?
But could this be condensation between the heated wall,and the cold air from outside,causing moisture on my floor sill,which appears to be wet.
Thanks,Phil

Is the wall in the garage covered? You could try putting xps foam in the cavity and sealing the edges.

**Gary in WA** · 01-25-2011, 11:58 PM

Phil, I'm going to move your post to "Building" and start your own thread, so Tj can have his back......

Gary

TJMS81 · 01-26-2011, 12:06 AM

Thanks GBR. Anyone have any suggestions on mounting the foam? It would be right up against the plywood for the roof. The roofing nails sticking through may be an issue as well.

Thanks to everyone in advance.

**Gary in WA** · 01-26-2011, 12:19 AM

Benjamin, could you go to Phil's post and repeat your questions, I'm new at moving things around.... Still trying.... Thanks.

Tj, I'll give you some good reading; http://www.buildingscience.com/docum...r-all-climates

Gary