AvoGuide · plasterboard sheet sizes
Plasterboard sheet sizes, joints and waste: estimating sheets, not just m²
Common 10 mm residential plasterboard in Australia comes 1200 or 1350 mm wide and from 2400 to 6000 mm long (check the manufacturer’s current range). Work out sheets from the wall and ceiling layout, not from total m² plus a guessed waste percentage: the right width and length can remove a whole row of joints.
Sheet sizes from the manufacturer
| Board (Gyprock) | Widths (mm) | Lengths (mm) |
|---|---|---|
| Plus 10 mm (walls; ceilings at 450 mm centres) | 1200, 1350 | 2400, 2700, 3000, 3600, 4200, 4800, 5400, 6000 |
| Supaceil 10 mm (ceilings up to 600 mm centres) | 1200, 1350 (900 WA only) | 2400, 2700, 3000, 3600, 4200, 4800, 5400, 6000 |
| Aquachek 10 mm (wet areas) | 1200, 1350 | 2400, 2700, 3000, 4200, 4800, 6000 |
Why the size changes joints and waste
Every joint is setting labour, and every offcut you can’t use is waste. Matching the sheet width to the ceiling height, and the length to the wall, cuts both.
From m² to sheets
Lay out each wall or ceiling with the sheet you will use, count the sheets, then add only the waste you can see in the layout. A blanket percentage hides the walls where you will waste a third of a sheet.
Worked example: a 4.8 m wall, 2.7 m high
| Sheet laid horizontally | Rows | Sheets | Board bought | Offcut |
|---|---|---|---|---|
| 4800 × 1200 | 2.7 ÷ 1.2 = 2.25 → 3 | 3 | 17.28 m² | 4.32 m² |
| 4800 × 1350 | 2.7 ÷ 1.35 = 2 | 2 | 12.96 m² | nil |
Ask which sizes the builder stocks
Some builders and plasterers standardise on one or two sizes. Ask which they stock, and measure to the sizes they will actually order.
Sources
- Gyprock — Plus 10 mm (product page)
- Gyprock — Supaceil (product page)
- Gyprock — Aquachek 10 mm (product page)
- Gyprock — The Red Book (installation guides)