I live in an old house with horsehair plaster walls. One of the walls in my living room has a large crack running the length of the wall. It appeared after someone sat on the sofa with a little too much enthusiasm and pushed it into the wall. I've tried repairing the crack but because the wall is now "squishy", the plaster can now be pushed in without much force, the crack reappears the first time anything touches it.
My question is, can I drywall right over the existing wall without much hassle? Or is there a better way? If this is the best/easiest way to fix this, how do I make the joints between the new drywall and the old, like the ceiling, look correct?
Best Answer
You can drywall over the plaster, but you'll have to do the entire wall and screw through the plaster into the lath/studs.
Alternatively, you can fix the plaster itself. The problem is, it's separated from the lath. The fix for this is to drill shallow holes into the affected area JUST DEEP ENOUGH to penetrate the plaster, not the lath. Drill the holes 4" apart in a grid pattern.
Then use a caulking gun and inject construction adhesive into each hole to create a glue layer behind the plaster between it and the lath.
Press the plaster up against the lath with a flat board, holding it ONLY UNTIL THE PLASTER STICKS. Don't leave the board there too long or the glue will grab it too. Slide the board up and down to keep it from sticking while the glue takes hold between the lath and plaster.
Allow it time to dry, then patch the holes and paint.