Originally Posted by hartkem
I am about to start installing registers in the ceiling of my house. The house has plaster not drywall. I am wondering what the proper way is to install the flanged boots. Do I simply sandwhich the plaster between the register and boot to hold everything in place or is it a requirement that they are fastened to a ceiling joist.
Yes, you can just screw the register to the boot and it will hold it in place. During new construction you would use boot rails to hold the boots in place.
You will need a friend to hold the boot in place while you screw the register in. If that is not an option, you can screw drywall screws into the boot to hold it in place. Just make sure that the register covers them up.