TRH-04Work out your wall type and choose the right fixingOn solid brick or block, drill and fit a proper masonry wall plug with a screw driven at least 25mm into the masonry. On a timber stud wall, find the centre of a stud (a line of screw heads under a magnet, a solid sound when you tap, timber dust from a pilot hole) and drive a wood screw straight into it — no plug needed. On a metal stud wall, a magnet sticks to screw heads, the tap sounds hollow, and a pilot hole brings out fine steel swarf; never use a plastic plug or wood screw here, as they strip straight through 0.5mm steel — use a self-drilling metal-stud fixing, and if the holder pulls or wobbles, fit a timber noggin behind the board first. On dot-and-dab plasterboard, the board sits 10–40mm off the brick on adhesive dabs, so use a long fixing that passes through the board and dab to grip the masonry behind, not a short plug that only holds the plasterboard. On lath and plaster, try to locate and screw into a timber lath the same way as a stud; if you can't hit one, use a fixing designed to spread load across at least two laths.