I am turning my 2-car attached garage (18.5’x24′ with a low hip roof – only rises 3′ at the center line) into a woodworking shop. It has a new insulated hurricane proof 16′ garage door (we live on the water in Florida’s west coast). Only one small window and a new entrance door to the exterior. The attached wall faces east, the garage door faces west. The small window and entrance door are on the north side. Part of the south wall is common with the main house. I just installed a new mini-split 1-ton air conditioner & heating system (works great even with NO insulation and open soffits). The garage has open soffits on three sides; there is no ridge or roof vents. I just put a new concrete tile roofing system on the entire house and garage (and I am unwilling to install any ridge vents now that the roof is new – at the time of the new roof I did not know that I was going to turn the garage into a shop). The roof rafters are 2×6 on 16″ centers.
I am seeking suggestions for how best to insulate the garage roof. I have had an estimate to install 5″ of icylene foam at a cost of $1,595. I’m told that I would then need to cover the foam with a 15-minute thermal barrier – whatever that is!
Thanks for your help.
Treasure Island FL