CP-05Work out what's behind the wall, and check for cables and pipesAt each bracket mark, run a stud detector or a small magnet slowly across the wall. A magnet that grabs onto something in a line suggests screw heads along a timber or metal stud. A dull, solid sound when you tap means masonry or a dot-and-dab dab; a hollow sound between two firmer points means you're between studs. If you're still unsure, drill a small 2-3mm pilot hole at the exact bracket centre: fine pale dust means plasterboard or plaster, coarse wood dust means timber, and shiny metal filings mean a metal stud. Cables and pipes can run almost anywhere in a wall or ceiling, not just in the 'safe zones', and cheap detectors can miss cables that are deep, in metal conduit, or hidden by a metal stud frame or metal-backed plasterboard. Use a detector, but still assume something could be there until you've proved otherwise. Before you drill anything, find your stopcock (usually under the kitchen sink) and check it turns, so you can shut the water off fast if you hit a pipe. If you have any doubt at all, isolate the relevant circuit at the consumer unit before drilling, and turn the water off at the stopcock before cutting into anything that could carry water.