BW-03Check what's behind the wall, and stay safeRun a cable and pipe detector over every mark, then still treat the wall as if something could be there — detectors miss deep cables, cables in metal conduit, and anything hidden behind a metal stud frame. 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're at all unsure, isolate the circuit at the consumer unit before drilling. Drill one small pilot hole at a test point: fine pale dust means timber stud or masonry, fine grey swarf means metal stud, and a hollow sound with no stud contact means you're between studs on plasterboard.