Plastering Calculator

Plastering Calculator estimates exactly how many plasterboards you need, plus skim and bonding plaster bags, Dri-Wall dot-and-dab adhesive, drywall screws, scrim tape and external corner bead — built for UK plasterers, dry-liners, and serious DIYers.

Enter your room length, width and wall height, pick which surfaces to board (walls, ceiling, or both), choose a UK plasterboard size, and the app returns total boards including waste, plaster bag counts at British Gypsum manufacturer coverage rates, adhesive bag counts, screw counts at BS 8000-8 fixing centres, scrim-tape rolls and external corner bead — plus an optional cost breakdown.

KEY FEATURES

• Four standard UK plasterboard presets — 1800×900, 2400×900, 2400×1200 (the trade default), and 3000×1200 large boards
• Four board types — Standard, Moisture-Resistant (bathrooms), Fire-rated, and Acoustic 15mm (party walls)
• Two fixing methods — Dot & Dab (solid walls) and Screw Fix (stud walls and ceilings)
• Thistle Multi-Finish skim plaster at 10 m²/bag (British Gypsum PDS)
• Thistle BondingCoat undercoat at 3.5 m²/bag at 8mm thickness (British Gypsum PDS)
• Gyproc Dri-Wall Adhesive at 5.76 m²/bag, ~2 boards per bag (British Gypsum FAQ)
• Drywall screws at BS 8000-8 fixing centres — 32 per board on walls, 48 per board on ceilings (230mm vs 300mm field centres)
• Half-perimeter scrim-tape rule on 90m rolls
• External corner bead in 2.4m galvanised lengths — walls only
• Walls / Ceiling / Walls & Ceiling surface modes — openings only subtract from walls
• Add doors and windows from preset sizes or custom dimensions
• Configurable waste percentage (5-25%, default 10% UK trade)
• Optional cost estimation per board
• Share results to text, email or messaging apps

CALCULATION ACCURACY

Constants and rules cross-referenced with British Gypsum Thistle Multi-Finish PDS, Thistle BondingCoat PDS, Gyproc Dri-Wall Adhesive FAQ, BS 8000-8:2023 (dry lining), and BS 4787-1 (internal doorsets). Each coverage rate and fixing-centre constant is cited inline in the source code for auditability.

WHO IT'S FOR

• Plasterers and dry-liners quoting jobs
• Builders and refurb contractors ordering materials
• Homeowners planning a renovation or extension
• DIYers boarding a single room