Garage insulation help please
Hi new member here and this site seems really great! I am trying to insulate my garage to convert it to a golf simulator for the winter months. I live in upstate NY in the suburbs of Rochester. My garage is roughly 29×21 and not currently insulated. I was hoping to do this by myself. The problem is I have 2 x 6 joists that span approximately 21 1/2 feet and they are 48 inch OC. So that won’t support plywood (the previous order has a couple pieces up there). There is no ridge vent and soffits are not vented. I have three or four what I believe our box vents on the top. I was thinking of doing fiberglass or Roxul on the walls, but stuck on ceiling. Could I just “create an attic with something light like Relectix”. Any help would be greatly appreciated because I am stuck and cannot go forward. Thanks.
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Reflectix is not going to help you. What is the intention for the attic space? Can you close it off completely? If so, you could add ceiling joists, put up drywall, and blow cellulose over the whole thing. If just a garage, it could probably be fine just like that, but you could consider adding some vents once it's all sealed off.
I have no intention for the attic space my only intention is to keep the warm air below when I am using it as a golf simulator in the winter. I was hoping to do this inexpensively so I could spend more money on the Simulator. My original intention was just to lay 2 inch thick RX over the joists.. I will only be heating it when I am in there
My guess is those long "joists" on 48" centers are probably rafter ties and not actually joists. Rafter ties operate in tention to keep the bottom of the "A" shape of a peaked roof's support structure from spreading apart from roof loads. With such long spans and wide spacings, you can't really suspend anything from those here.
The simplest solution is probably to run some I joists or trusses across the narrow dimension of the space, spacing those so that you can use 2x4 or 2x6 framing between them to build out a ceiling support structure. This isn't a typical DIY project unless you have framing experience. An architect or engineer would be able to draw you up a design for this pretty easily though.
Once you have that structure in place, you could use loose fill above it (cellulose or fiberglass blown insulation), or batts. If it's just a seasonal garage with some minimal heating in the winter, I might use batts if it's your own (free) labor, but loose fill is going to go a lot faster. The interior side would just need to be drywall. I'd advise 5/8" drywall here due to the fire code requirements for a garage -- even if it's not really being used as a garage, building officials tend to be sticklers for anything considered "life safety", and that often includes things like this.
Bill
Thanks for the reply all that makes perfect sense to me and you’re probably right that they’re not joists.. that’s why I was hoping I could do something that would just keep the heat in the garage below when I’m using it I would never use the attic space for anything