I have a few ceiling registers which are not flush with the ceiling since the duct has loosened over time. What's the best way to get them flush with the ceiling? I thought about driving several sheet metal screws into them but they would go into drywall which has only so much holding strength. Is there a better method? Thanks
Drill a hole on either side of the register. Mark the holes on the ceiling with a pencil, drill and install a drywall anchor in each location. Secure the register with screws into the anchor.
Some people paint the ceiling and the register so it blends in better (and covers the screw heads).
I cut thin strips of cardboard (small enough to fit in screw hole) and poked them in the holes. Screws tightened nicely. All you are trying to do is give the screw something to hold to. Don't overfill or pack the hole.
I found some more registers that the previous homeowner completed stripped the screws on. I put a glob of JB weld on the problematic hole, completely covering it. Came back the next day and drilled a small hole through it and carefully screwed in the register. I was skeptical but it held very well and tight! On another register I drilled another hole into the sheet metal to solve the same problem. BTW, I highly recommend a socket and not screwdriver for removing/tightning.