|
Recommended
Timber Batten Sizes
(roofing & vertical applications)
| 450 |
1 no 75mm x 3.35mm |
38 |
25 |
| 600 |
1 no 75mm x 3.35mm |
50 |
25 |
| 900* |
1 no 100mm x 4.00mm |
50 |
50 |
| 1200* |
1 no 100mm x 4.00mm |
50 |
50 |
| 1500* |
1 no 125mm x 12g screw |
50 |
75 |
| *underlay
supports between rafters/truss to be
used, (wire support or nylon tape). |
Recommended
Roofing Underlay
| Unsupported (roofing
underlay draped over rafters or counter-battens) |
Roofing underlay should
comply with BS747 type 1F or 5U |
| Fully supported (roofing
underlad laid directly to boarding or
sarking) |
Roofing underlay should
compy with recommendations of BS5534:
Part1: 1997 section 2.10.2 and vapour
transmission tested in accordance with
BS3177 (NB. good quality BS747 type
1F underlay comply with this test) |
Recommended Laps
for Underlay
| 12° |
300mm |
200mm |
100 - 150mm |
| 12.5° to 14° |
225mm |
150mm |
100 - 150mm |
| 15° to 34° |
150mm |
100mm |
100 - 150mm |
| 35° & above |
100mm |
75mm |
100 - 150mm |
| NB. Any penetrations
to the underlay should be suitably sealed
to prevent water ingress. Roofing underlay
laps to valleys should comply with recommendations
of BS5534: Part 1: 1997 section 4.2.1.6. |
Calculation Chart
(estimating guide for 0.45 only)
Chart below allows for
a 25mm fascia and 20mm to the first batten.
| 1.250 |
1 |
0.294 |
1 |
| 2.500 |
2 |
0.663 |
2 |
| 3.750 |
3 |
1.032 |
3 |
| 5.000 |
4 |
1.401 |
4 |
| 6.250 |
5 |
1.770 |
5 |
| 7.500 |
6 |
2.139 |
6 |
| 8.750 |
7 |
2.508 |
7 |
| 10.000 |
8 |
2.877 |
8 |
| 11.250 |
9 |
3.246 |
9 |
| 12.500 |
10 |
3.615 |
10 |
| 13.750 |
11 |
3.984 |
11 |
| 15.000 |
12 |
4.353 |
12 |
| 16.250 |
13 |
4.722 |
13 |
| 17.500 |
14 |
5.091 |
14 |
| For wastage
on Hips & Valleys, allow an additional
1.32 slates per 1m. |
|
