BP-06Fix the battens to the wall — method depends on what's behind itOn solid brick or block, drill 6mm holes 40mm deep, insert wall plugs and drive 40mm screws. On plasterboard over timber studs, screw a 40mm wood screw straight into the centre of each stud, checked with a pilot hole. On plasterboard over metal studs, use self-drilling metal-stud screws where a stud lines up, and hollow-wall toggle fixings for the plasterboard between studs — never a plain wall plug or wood screw, which will strip straight through 0.5mm steel. On dot-and-dab plasterboard, use a fixing long enough to pass through the void and grip the masonry behind, usually 60-75mm. On lath and plaster, find the timber lath by drilling a small pilot hole first and feel for wood; if you hit only plaster, use a spring toggle rather than hammering a plug into brittle lath.