Adding fire rating drywall over coved ceilings
I'm about to add a suite to a 1930s house and am required by code to add 1-hr fire rating drying to the ceilings of the main floor for the additional suite upstairs. I don't want to tear down the lathe and plaster coved ceilings and send it all to the landfill, but is there a way to install 2 layers of drywall to a ceiling with coved ceilings that's not excessively expensive?
Find the joists and make a mark on the wall to indicate the center of the joists. Determine the the thickness of the lath and plaster, add the thickness of the drywall. Use drywall screws at least 1 inch longer than the combined thickness. When installing the 2nd layer make sure the seams on the 2nd layer are not over the seams of the 1st layer. If you are not experienced at hanging drywall this will be a very hard job to do.