Advanced options
Standard 12.5mm board for walls; use moisture-resistant (green) board in bathrooms and kitchens, fire-rated (pink) where regulations require, and acoustic board between dwellings. Screws at 300mm centres on walls, 230mm on ceilings.
What The Plasterboard Calculator Works Out
- Area to board: length x height for a wall, or length x width for a ceiling, in square metres. Ceilings go up before walls, and boards run with their bound edges across the framing.
- Boards needed: the area plus 10% for cuts around openings, divided by the board's area, rounded up. A 5m wall at 2.4m high is 12 m2 and five 8x4 (1200 x 2400mm) boards. The 8x4 is the workhorse because 1200mm matches stud centres at 400 or 600mm and 2400mm matches standard ceiling heights; the smaller handy boards trade more joints for a one-person lift.
- Fixings and finishing: about 30 drywall screws per board, a roll of scrim tape per 20 m2 and a bag of joint compound per 8 m2 for a taped finish. Screws go at roughly 300mm centres on walls and 230mm on ceilings, heads just dimpled below the paper, with joints staggered between rows.
- Board types: standard 12.5mm suits most walls, 9.5mm bends to curves and lightweight ceilings, moisture-resistant green board goes in bathrooms and behind sinks, fire-rated pink board where regulations require (protected escapes, garage ceilings), and acoustic or double-layer boarding quietens party walls.
- Openings and waste (advanced): deduct doors and windows (a door is about 2 m2) and adjust the waste: 5% for a plain ceiling, 15% for a room with lots of reveals and boxed-in pipework.
- Layers of board (advanced): doubles the board count for acoustic or fire-rated double layers, with the second layer screwed through to the studs with longer screws.
- Fixing method (advanced): switches from screws to dot-and-dab adhesive for boarding straight onto masonry, at about 3 m2 per 25kg bag of drywall adhesive.
- Finish (advanced): tape and joint (scrim plus two or three feathered coats of compound) gives a paint-ready surface without wet plaster and is within a careful DIYer's reach. A full 2 to 3mm skim of finish plaster is the traditional dead-flat finish and a genuine trade skill; a 25kg bag covers about 10 m2.
- Board cost and labour (advanced): boards x your price (standard 8x4 boards are typically GBP 8 to GBP 14, moisture-resistant and fire-rated more) plus the area x a dryliner's or plasterer's rate. Boarding and skimming together commonly costs GBP 25 to GBP 45 per m2 in the UK. Hire a plasterboard lifter for ceilings; it spares both the board and your spine.