AB-05Fix the back batten to the wallHold the batten on your marked line and check it's level, then fix it according to what step AB-02 told you. Solid brick or block: drill 6mm holes 40mm deep, insert a wall plug, and use a 50mm woodscrew every 300-400mm. Timber stud: drive a 60mm woodscrew through the batten and plasterboard into the centre of each stud, with at least two fixings across the batten's length. Metal stud: use a self-drilling metal-stud screw where a stud lands under the batten — never a plain wall plug or wood screw, which strips straight through 0.5mm steel — and use a toggle-type hollow-wall anchor rated for the shelf's load anywhere the batten falls between studs. Dot-and-dab: drill through carefully with a long masonry bit first to find the depth of the air gap behind the board, then use dot-and-dab frame fixings at least 75-90mm long to reach the solid wall behind. Lath and plaster: this surface is brittle and springy, so locate the timber studs behind the laths and screw into those only, spacing fixings so the batten spans at least two studs to spread the load.