SK-06Match your technique to the wall typeOn solid brick or block, fixings are usually masonry nails or screws into wall plugs - you can lever fairly firmly, but ease off if the plaster skim starts to crack away from the brick. On plasterboard over timber studs, the skirting is screwed or nailed into the stud or a noggin behind - lever only at those points, as levering between studs can tear the plasterboard's paper face. On plasterboard over metal studs, fixings are screws into the stud or track behind thin plasterboard - this crumbles more easily, so lever in small movements and expect a few soft, crumbly holes at each point. On dot-and-dab walls, long screws often pass through the plasterboard into the dabs of adhesive holding it to the masonry - lever close to each fixing, not between dabs, or you risk pulling a whole sheet of plasterboard off the wall. On lath and plaster, fixings are usually nails into timber laths behind old lime plaster - laths are brittle, so work slowly and stop if you feel the plaster keys crack.