If your ceiling drywall is sagging between joists, sometimes called “pillowing,” it’s probably on the top floor and attached to the roof trusses. If so, there’s a good chance the installers used ...

Q Am I right that when sections of plaster break away from the lath, an accepted repair technique is to roughly fill in those gaps with drywall and then drywall over the whole wall or ceiling? — M.H., ...