UR-03Work out what's behind the wallKitchen walls vary a lot — even the same room can mix solid brick, dot-and-dab plasterboard, a timber or metal stud wall, or old lath and plaster. Tap along the marked line: a dull, solid knock usually means brick or block, and a hollow knock means plasterboard or lath and plaster. On a hollow-sounding wall, run a detector or a small magnet across the surface to pick up the line of screw heads fixing the board to the frame behind — that line shows you where the studs are. Drill a small 2mm test hole at a stud mark: pale wood dust means a timber stud, and fine grey swarf means a metal stud, which is common in flats, new-builds, and any kitchen refitted since the 1990s. Lath and plaster feels slightly springy and gives a hollow knock with a faint echo — the wall is a lattice of thin timber laths under the plaster, not a solid board.