NB-05Drill and fit the right fixing for your wallFor dot-and-dab, drill through the plasterboard and the void behind it into the solid masonry using a 6mm masonry bit, checking your drill goes noticeably deeper before it hits solid material — the fixing needs to reach at least 40mm into the brick or block itself, so use a long fixing (typically 75-100mm) that spans the void, with a matching plug pushed fully into the masonry. For solid brick or block with no board, drill straight in with a 6mm masonry bit to 40-50mm depth and use a plug and screw of matching length. If the wall turns out to be a timber stud wall instead, drive a 4mm wood screw at least 40mm long into the centre of the stud with a pilot hole first. If it's a metal stud wall, never use a plain plastic plug or ordinary wood screw — they strip straight through 0.5mm steel — use a self-drilling metal-stud fixing or a hollow-wall toggle rated for the weight; a whiteboard is light, but if you're mounting anything heavier or that will get pulled on, fit a timber noggin between the studs first or fix through to the masonry behind. For lath and plaster, the old plaster is brittle and can crack, so drill gently through to the wooden laths or the joist behind and use a longer screw that bites into solid timber, not just the plaster skin.