Sleepers below rigid over garage?
I’m looking at the GBA details for insulated floors above garages and see that both use sleepers between the rigid foam under the floor trusses and the drywall ceiling.
Why not just attach the drywall through the foam? Any differences in the way you would do the assembly for an attic truss instead of the floor trusses shown?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
You call them sleepers, we call them furring strips. It's a New England detail. Almost all New England ceilings get strapped with 1x3 or 1x4 furring strips. It's traditional.
If you want to install drywall directly against your rigid foam, you can. Just use long screws.
The detail has them labeled as "sleepers". We call them furring strips in Ohio too. Interesting tradition. Does it make the ceiling flatter?
If you can provide a link to the detail, I'll have a better idea of what you are talking about.
If the ceiling joists aren't quite co-planar, furring strips make it easier to create a flat ceiling, because the furring strips are easy to shim. And if there is a layer of rigid foam on the ceiling, the furring strips make it much easier to attach the drywall.
Here is one of the details in the group "Insulated floor above Garage":
Thanks for helping me understand the nuances of the detail!
Thanks for the link. I hadn't realized that ceiling furring strips were labeled "sleepers" in the GBA details. Now I know.