I bought a post-war story-and-a-half about a year ago. It had some minor water damage, due to ice-dam roof leaks that are so typical of the design. A new roof was put on, about five years ago, and when I bought it the inspector said the interior was bone-dry. But the plaster ceilings have a few cracks and some sloppy patches, made more obvious by a poorly applied textured ceiling.
I "fixed" one bedroom by scraping the popcorn, fixing the cracks with chisel, tape, and compound, sanding, priming, and painting. I'm not really happy with the result.
I've been looking at the second bedroom, and considering my options. I'm leaning towards laminating with 1/4 drywall.
The existing ceiling is built on rock lath, and it's solidly attached. I don't see reason why it should need to come down. The problems are only cosmetic. Beyond that, it's level and flat. I skimmed a laser-level over the surface, and aside from a bit of protrusion where the patch was done, it seems to be at least as straight as I could manage to get with firring strips.
It seems to me that that the drywall would cover a multitude of sins, but that that lumpiness is the one it could not cover. Cracks and depressions would not force the drywall sheets from lying in plane, but a lump would. Not just force the drywall out of plane, but tend to pull the edge of the board so as to make an uneven joint.
So I plan on sanding the patch down until it's in-plane again, and then rent a drywall lift and screw the panels into place. I'm anything but a fast worker, but I think I can manage to get eight panels in place on a single day's rental. Jointing I can take my time at.
I have three main questions.
1: Is this a reasonable way of dealing with the problem? The existing plaster is firmly in place, it seems absurd to go through the work of tearing it out simply to replace it with a lower quality substitute like drywall.2: What fasteners should I use? Drywall screws? Drywall nails? Something else? Through the plaster into the joists, of course, but how far apart? Should I add additional fasteners along the edges between the joists? In the interior of each panel, not along the joists?
3: How do I treat the corners? Run joint tape and compound along the valley?Help would be appreciated.