SR-03Work out what your wall is made ofTap the wall along your marked line. A solid, dull thud with no give is solid brick or block. A hollow sound that changes as you move sideways, with a slight bounce, usually means plasterboard on dot-and-dab or on studs. A very hollow, springy, sometimes crackly feel in an older house often means lath and plaster. If it's a stud wall, use a detector or magnet to trace the line of screw heads holding the plasterboard on, and drill one small pilot hole at a mark: fine wood dust means a timber stud, fine grey metal swarf means a metal stud.