TV-02Work out what your wall is actually made ofRun a stud or cable detector across the wall. A steady line of hits every 300mm or 600mm means a stud wall — tap between the hits, and a hollow sound with no give means plasterboard between the studs. Drill a small pilot hole in an inconspicuous spot: fine grey swarf means a metal stud, pale wood dust means timber. If the wall sounds solid all over with no hollow patches, it's likely brick or block, or dot-and-dab (solid-sounding near the edges, hollow in the middle). If it flexes slightly and sounds different from modern plasterboard, it could be lath and plaster — old timber laths under a plaster skim, common in pre-1930s houses.