Garage attic insulation
SRQOwner| Posted inGeneral Questionson
Attached 2 car garage in S FLorida on east & south side of house is always in the 90’s – overnight it cools to only around 88. Although the contract called for 12 3/4″ Fiberglass, R-19 insulation, there is no insulation. Drywall ceiling. Will insulating make the garage temps more reasonable? One installer quoted me for R-38 mats.
What about soffits – there are none? Will that help, or a vent installed in roof. Metal roof.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
Insulating the garage attic will definitely help! Venting might help too: ideally both soffit vents and a ridge vent. It can make sense to do that at the same time as the insulation, since access is easier without the insulation.
12-3/4" of insulation is about the same as R-38.
If the contract called for insulation and there is none, can you ask the other party in that contract to do it, or pay for it.
Thanks for reply. The "other party" is already party to a lawsuit with me (and 6 other customers that I know of), so he's not going to do it. So I pay - doubtful I'll ever get paid back.
I have 2 quotes - one of which was from the Sub that did the rrest of house, but builder told him to not do garage(And this house is supposedly Green Build Certified). One proposal is for the fiberglass, the other for spray foam. Is one better than the other. The fiberglass is much cheaper. If foam, can we be in the house when it is being done, or right afterwards?
Before insulating, make sure the ceiling is airtight. This can make a bigger difference than R5 vs. R50 insulation. Blown cellulose is more common for attics but blown fiberglass can work. I steer clear from spray foam whenever possible-- there are simpler means of getting the ceiling airtight and you can get a lot more R value for your money with the alternatives.