TB-04Fix a temporary level batten above the bathUse a spirit level to mark a line one tile height (plus a spacer gap) above the bath rim — this batten carries the weight of the first row while the adhesive sets. Before you drill: cables and pipes can run almost anywhere. Use a detector, but still treat the wall as if something is there and prove it isn't — detectors miss deep cables, cables in metal conduit, cables behind metal-backed plasterboard, and metal stud frames confuse cheap detectors further. Find your stopcock (usually under the kitchen sink) and check it turns before you start, so you can shut the water off fast if you hit a pipe. If there's any doubt, isolate the circuit at the consumer unit before drilling. On solid brick or block, drill a 6mm hole to 40mm depth and use a wall plug with a 40mm screw. Into a timber stud, drive a 45mm wood screw straight into the centre of the stud — no plug needed. Into a metal stud, use a self-drilling metal-stud screw or a toggle fixing rated for the load — never a plastic wall plug or an ordinary wood screw, they strip straight through 0.5mm steel. Through dot-and-dab, use a fixing long enough to pass through the plasterboard and the dab void into the solid masonry behind, typically 60–75mm with a plug. On lath and plaster, the laths won't hold a screw on their own — find the timber stud or joist behind with your detector and fix into that instead.