BM-06Choose the right fixing for what you foundIf you hit a timber stud, use a pilot hole and a stainless wood screw (40-50mm) driven into its centre – stainless resists rust in a bathroom. If you're between studs, over laths only, never use a plain plastic wall plug, as it will pull straight through crumbly lime plaster; use a spring toggle or a hollow-wall anchor made for old lath and plaster, rated for the mirror's weight. If your test hole showed solid masonry behind battens, drill with a masonry bit and use a plastic wall plug (6-8mm) sized to a 50-60mm screw. If it turned out you actually have dot-and-dab plasterboard, use a fixing long enough (75-100mm) to pass through the board and the adhesive dabs into the masonry behind; if it turned out you have metal studs, never use a wood screw or wall plug – it strips straight through 0.5mm steel – use a self-drilling metal-stud fixing or toggle instead, and remember a metal stud alone won't hold a heavy mirror, so fix into a timber noggin or through to the masonry behind if the mirror is large or heavy.