LP-04Check for cables and pipes, then drill your fixing holesBefore drilling, find your stopcock (usually under the kitchen sink) and check it turns fully, so you can shut off the water fast if you ever hit a pipe. Sweep the whole marked area with your detector, but treat it as a guide, not a guarantee — detectors miss deep cables, cables in metal conduit, and anything hidden by old lath and plaster's own nails and mesh. If you have any doubt, isolate the circuit at the consumer unit before drilling, and turn off the water at the stopcock before cutting into any wall that could hide a pipe. Drill your fixing holes to the size set out for your wall type in the next steps, stopping every 10mm to check the dust and how much resistance you feel.