Why should I not use plasterboard screws for everything?
They are cheap, they are in every toolbox and they are the wrong screw for most jobs — the three properties that make them good at one thing and bad at the rest.
- Difficulty
- beginner
- Time
- 8 min
- Read
- 2 min
Short answer
Plasterboard screws are made hard and brittle, thinly phosphate-coated with no corrosion protection, and shaped with a bugle head and a fine thread for gypsum. That makes them excellent at fixing board to a stud and poor at almost everything else: they snap under shear, they rust wherever there is any moisture, and they have very little pull-out strength in timber.
The black screws in the big cheap box are the most over-used fastener in domestic DIY. They exist for one purpose — attaching sheets of plasterboard to timber or metal — and every feature that makes them good at that makes them unsuitable elsewhere.
Step by step
- Understand what makes them brittle.They are heat treated hard so that a high-speed collated driver does not chew out the recess. Hard steel does not bend before it breaks, so under shear or bending load they snap suddenly with no warning at all.
- Understand the coating.The black finish is a thin phosphate, which is a paint key and a lubricant, not a corrosion barrier. In a bathroom, a garage, an unheated loft or anywhere outdoors they will rust, and they will bleed rust through any decoration over them.
- Understand the head.The bugle head has a curved cone that compresses the paper face of plasterboard rather than tearing through it. In timber that shape has a small bearing area and pulls straight into softwood.
- Understand the thread.Fine and shallow, designed for gypsum and thin steel. It has far less grip in timber than a coarse construction screw of the same diameter.
- Use them where they belong.Board to timber studs, board to metal studs with the fine-thread version, and holding a temporary piece in place while glue cures. That is the list.
- Use a construction or wood screw everywhere else.Anything carrying load, anything outdoors, anything in a damp room, anything holding a bracket, anything holding timber to timber.
- Never use them for a fixing whose failure matters.A shelf bracket, a handrail, a gate, a TV bracket, a stair component. They are not rated for it and the failure mode is sudden.
Tips
- The coarse-thread black screws are for timber studs and the fine-thread ones for metal studs. Using the coarse type in metal stud simply strips the thin steel.
- If you can only find plasterboard screws for a temporary job, that is fine — that is genuinely what they are good for.
- A snapped plasterboard screw is one of the harder extractions there is, because it is often harder than the extractor. That alone is a reason to keep them out of load-carrying work.
Common mistakes
- Using them to fix skirting, architrave or battens — Poor pull-out in timber, they rust behind decoration, and the small head pulls into softwood. Use a proper wood screw.
- Using them outdoors on a temporary structure — They lose section to rust quickly and shear under wind load. A fence prop or a hoarding wants a construction screw.