What Size Drywall Screws Do I Need? A Plasterboard Fixing Guide
Drywall screws look simple, but using the wrong length or type is behind a lot of popped screw heads, loose boards and snapped points. This guide covers the length rule, which screw suits timber or steel, how far apart to put them and roughly how many you will get through. We now stock the Evolution Fasteners range in full cartons, so we have used their sizes throughout.
The length rule
British Gypsum's guidance is that a drywall screw should be the thickness of the board plus:
- at least 10mm of penetration into metal studs, track or ceiling sections, or
- at least 25mm of penetration into timber.
Round up to the next size available. Using common Evolution sizes, that gives:
| Board | Into metal framing | Into timber |
|---|---|---|
| 9.5mm | 25mm | 38mm |
| 12.5mm | 25mm | 38mm |
| 15mm | 25mm | 42mm |
| 2 × 12.5mm (face layer) | 38mm | 50mm |
| 2 × 15mm (face layer) | 42mm | 65mm |
With two layers, the base layer is fixed with the shorter screw and the face layer with the longer one. For insulated plasterboard, add the full board thickness, insulation included, and follow the manufacturer's fixing guidance.
Timber or steel: choosing the right screw
Coarse thread for timber
Coarse thread screws bite into softwood studs, joists and battens and hold well. Evolution coarse thread black phosphate drywall screws are made for timber studs and come in sizes from 3.5 × 25mm to 4.8 × 170mm.
Sharp point for light steel
For fixing into standard metal studs, track and MF ceiling sections, use a drywall screw designed for light-gauge steel. Evolution Premium zinc-plated drywall screws are rated for steel up to 1.2mm. At the time of writing, a carton of 10,000 in 3.5 × 25mm is £30.43 ex VAT.
Self-drilling for heavier steel
Heavier-gauge sections, such as some I studs and other thicker framing, need a drill-point screw. Evolution's self-drilling drywall screws are rated for steel up to 2.5mm.
Collated screws for autofeed guns
On bigger jobs an autofeed screw gun saves a lot of time. Evolution collated coarse thread screws come on strips to suit these tools, and fine thread and self-drilling collated versions are also available.
Specialist boards such as cement-based or high-density boards often need their own screws. Check the board manufacturer's guidance, and see the full Evolution drywall and collated screws range.
How far apart should drywall screws be?
British Gypsum's good practice guidance for single-layer boards is:
- Walls and partitions: 300mm maximum centres, reduced to 200mm at external corners.
- Ceilings: 230mm maximum centres in the field of the board and 150mm at board ends.
- Edges: no closer than 10mm to a bound (paper-covered) edge or 13mm to a cut edge.
Drive each screw so the head sits just below the surface without tearing the paper. A torn face will not hold, so add another screw nearby rather than overdriving.
How many screws will I need?
On a wall with studs at 600mm centres and screws at 300mm, a 2400 × 1200mm board takes about 27 screws. A carton of 10,000 therefore covers roughly 370 boards on walls, or around 1,000m² of single-layer lining. Ceilings, closer stud centres and double layers use more. Our drywall partition calculator and MF ceiling calculator both include screws in the materials list.
Frequently asked questions
Can I use wood screws to fix plasterboard?
It is not recommended. Wood screws have a different head shape that tends to tear the paper face. Bugle-head drywall screws are designed to sit flush without breaking it.
Black phosphate or zinc?
Both are for internal drylining. Black phosphate is the standard finish, while zinc plating gives a little more resistance to corrosion. For damp or exposed locations, use a screw that the board or system manufacturer specifies for those conditions.
For more on board types, see our guide to plasterboard for drylining.
Order Evolution fixings
Evolution fixings are sold in full cartons, and prices are shown ex VAT. We deliver across mainland England and Wales; Evolution fixings delivery is £15 ex VAT with no minimum order. See our delivery information for details. Call us on 03330 908479, email sales@insulationwarehousedirect.co.uk, or order online.
Sources: British Gypsum Drywall Screws product data sheet; British Gypsum Site Book good practice guide (screw centres and edge distances); Evolution product listings for sizes and ratings. Correct at the time of writing.