Plasterboard & Drywall Calculator
Calculate plasterboard sheets, screws, joint tape, and jointing compound for any room. Works for dot-and-dab, stud walls, and ceiling installations.
Plasterboard Guide
Standard Sheet Sizes
Standard UK plasterboard is 2400×1200mm (8×4 feet). This covers 2.88 m² per sheet. Also available: 2700×1200mm, 3000×1200mm, and 900×1800mm (for tight spaces). Standard thickness: 9.5mm for ceilings (lighter weight), 12.5mm for walls, 15mm or 19mm for fire-rated partitions. Moisture-resistant (MR, pink or green board) for kitchens and bathrooms. Impact-resistant for high-traffic areas. Fire-resistant (pink board, Fireline) for fire separation requirements.
Screw Spacing
Timber stud walls: screws at 300mm centres along each stud, 150mm centres on perimeter edges. Maximum 50mm from sheet edge, minimum 10mm. Use drywall screws: 25mm for 9.5mm board on timber, 38mm for 12.5mm board. Metal stud partitions: use wafer-head self-drilling screws. Dot and dab (directly to masonry): use 100mm+ screws into wall plugs at 600mm centres. One 500-screw tub typically covers approximately 15–20 sheets. Count linear metres of stud or batten to calculate screws precisely.
Finishing Joints
All tapered (long) edges are jointed with paper tape and jointing compound applied in three coats (filling, topping, finishing), feathered out 200–250mm either side of the joint. Cut (short) edges need to be rebated or chamfered before taping, or use scrim tape with a flexible filler. Each coat must be fully dry before the next — typically 12–24 hours. Sand lightly between coats with 120-grit. Skim plaster over the entire surface gives the best finish but requires plastering skills; using a fine
Sound and Thermal Insulation
Standard plasterboard provides minimal sound or thermal insulation on its own. For party walls (between properties): use acoustic plasterboard, double layers, or resilient bar systems. For thermal: insulated plasterboard (PIR foam bonded to board, 25–50mm total) significantly improves wall U-values for dot-and-dab applications. For fire separation (Building Regulations Part B): two layers of 12.5mm standard board or one layer of 15mm fire-resistant board on each side of a stud partition provides
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