How it’s worked out
- Wall area = 2 × (length + width) × height, less about 1.7 m² per door and 1.5 m² per window. We don’t subtract small openings, because the offcuts rarely get used.
- Sheets = area × 1.1 ÷ sheet area (1.2 m × sheet length), rounded up, with walls and ceiling counted separately.
- Screws: a rough allowance of about 10 per m² on walls and 12 per m² on ceilings. Fixing patterns vary by product and whether you also use adhesive, so follow the manufacturer’s fixing guide.
- Joint tape: about one metre of recessed-edge joint for every 1.2 m² of board, plus 15% for butt joints and corners.
- Cornice = the room’s perimeter plus 10%, in standard lengths.
Patching rather than re-sheeting? See how to patch a hole in plasterboard. Painting afterwards? Use the paint calculator.
Questions
How many plasterboard sheets do I need for a room?
Work out the wall area (perimeter × height) and ceiling area, subtract large openings, add about 10% for cuts, then divide by the area of one sheet. A 2400 × 1200 mm sheet covers 2.88 m².
What thickness plasterboard for walls and ceilings?
In Australian homes, 10 mm is standard for walls and commonly used for ceilings on battens at standard spacings; 13 mm is used for ceilings with wider framing spacings or where more sag resistance is needed. Wet areas need wet-area (water-resistant) board. Check the manufacturer’s span and fixing tables.
What sheet length should I buy?
Pick a length that spans the wall with the fewest butt joints. Sheets are usually laid horizontally on walls, so a 3600 mm sheet along a 3.6 m wall avoids a join entirely.
Is plasterboard sheeting DIY-legal?
Yes, hanging and setting plasterboard is DIY-legal. Anything behind it isn’t: moving power points, switches or cables needs a licensed electrician, and plumbing needs a licensed plumber. Homes built before 1990 may have asbestos sheeting, so get older sheet material tested before removing it.
Estimates only. Check the product label and your measurements before you buy. More free tools: see them all.