| Board thickness | Max centres | US equivalent | Studs per 1200mm board |
|---|---|---|---|
| 9.5 mm plasterboard | 400 mm | ~16 in OC | 3 |
| 12.5 mm plasterboard | 600 mm | ~24 in OC | 2 |
| Gauge | Typical diameter | Common use |
|---|---|---|
| No. 4–6 | 2.9–3.5 mm | Small hinges, light fittings, cabinet hardware |
| No. 8 | 4.2 mm | General DIY — shelving brackets, most fixtures |
| No. 10 | 4.8 mm | Heavier shelving, door furniture, decking |
| No. 12–14 | 5.5–6.3 mm | Structural timber connections, heavy brackets |
The same weight needs a completely different fixing depending on what's actually behind the surface. A timber or metal stud, found with a stud finder or the knock test, is always the strongest option — a wood screw driven straight into solid timber comfortably out-holds almost anything you'd hang in a home. Solid masonry needs a wall plug sized to the load. Plasterboard with nothing solid behind it is the trickiest case: the board itself is the weak point, not the fixing.
An 18 kg TV bracket on plasterboard with no stud nearby is a genuinely risky fixing even spread across multiple standard plasterboard plugs — independent destructive testing has found plasterboard itself typically fails around 60 kg of straight pull-out force regardless of fixing type, and trade guidance is to never load a fixing beyond roughly a third of that peak — meaning a safe practical ceiling of about 20 kg per fixing, at best. The right call here is a timber batten fixed across two studs, or finding the stud directly.
Packet ratings often describe shear load (force pulling down, parallel to the wall) rather than axial load (force pulling straight out) — a picture hook is mostly shear, a shelf bracket or TV mount is mostly axial, and axial is the harder case for any plasterboard fixing to resist.
An electronic stud finder detects the density change; a strong magnet will stick to the screws or nails already in the stud; tapping across the wall gives a dull "thud" over a stud versus a hollow ring in the gap between them. Combine two methods if you're hanging anything heavy enough to matter.
No — removing the screw drops the wings into the wall cavity permanently. A snap-toggle or a self-drilling plasterboard screw are the fixings to reach for if you might want to move the item later.
Standard plasterboard fixings only grip the board itself, which is often only glued to the masonry behind at intervals — for anything heavy, drill through to the masonry and use a wall plug rated for the actual load, long enough to reach solidly past the adhesive gap.