How many slates per square metre (m2)?
This table shows the required number of slates per square metre for effective coverage.
The number of roof slates that are needed depends on the slate size and the lap in mm.
| Quantity of Slates | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Slate Size | Lap mm | |||||||||||
| (Nominal) mm | 50 | 65 | 75 | 80 | 90 | 100 | 110 | 115 | 120 | 130 | 140 | 150 |
| 600 x 300 | 12.1 | 12.5 | 12.7 | 12.8 | 13.1 | 13.3 | 13.6 | 13.7 | 13.9 | 14.2 | 14.5 | 14.8 |
| 500 x 300 | 14.8 | 15.3 | 15.7 | 15.9 | 16.3 | 16.7 | 17.1 | 17.3 | 17.5 | 18.0 | 18.5 | 19.0 |
| 500 x 250 | 17.8 | 18.4 | 18.8 | 19.0 | 19.5 | 20.0 | 20.5 | 20.8 | 21.0 | 21.6 | 22.2 | |
| 450 x 300 | 16.7 | 17.3 | 17.8 | 18.0 | 18.5 | 19.0 | 19.6 | 19.9 | 20.2 | 20.8 | 21.5 | |
| 400 x 250 | 20.2 | 20.8 | 21.3 | 21.6 | 22.2 | 22.9 | 23.5 | 23.9 | 24.2 | 25.0 | 25.8 | |
| 450 x 230 | 21.7 | 22.6 | 23.2 | 23.5 | 24.2 | 24.8 | 25.6 | 26.0 | 26.3 | 27.2 | 28.1 | |
| 400 x 300 | 19.0 | 19.9 | 20.5 | 20.8 | 21.5 | 22.2 | 23.0 | 23.4 | 23.8 | |||
| 400 x 250 | 22.9 | 23.9 | 24.6 | 25.0 | 25.8 | 26.7 | 27.6 | 28.1 | 28.6 | |||
| 400 x 200 | 28.6 | 29.9 | 30.8 | 31.3 | 32.3 | 33.3 | 34.5 | 35.1 | 35.7 | |||
| 350 x 300 | 22.2 | 23.4 | 24.2 | 24.7 | 25.6 | 26.7 | 27.8 | |||||
| 350 x 250 | 26.7 | 28.1 | 29.1 | 29.6 | 30.8 | 32.0 | 33.3 | |||||
| 350 x 200 | 33.3 | 35.1 | 36.4 | 37.0 | 38.5 | 40.0 | 41.7 | |||||
| 320 x 220 | 33.7 | 35.7 | 37.1 | 37.9 | 39.5 | 41.3 | 43.3 | |||||
| 320 x 180 | 41.2 | 43.6 | 45.4 | 46.3 | 48.3 | 50.5 | 53.0 | |||||
| 300 x 200 | 40.0 | 42.6 | 44.4 | 45.5 | 47.6 | 50.0 | ||||||
| 300 x 150 | 53.3 | 56.7 | 59.3 | 60.6 | 63.5 | 66.7 | ||||||
