Fittings and fixings
Nails and clips for tiles and slates (to the fixing specification)
- where
- nails
- total tiles or slates
- perimeter tiles
- nails per main-area tile
- nails per perimeter tile
- spare allowance (%)
- clips, hooks or rivets
- clips per main-area tile
- clips per perimeter tile
Explain this equation
Counts the nails and clips needed once you know the fixing specification for the main roof and the perimeter. Use it when ordering fixings for a re-roof.
Tiles at eaves, verges, ridges and abutments get more wind uplift, so the specification usually asks for more fixings there. N − N_p is the number of main-area tiles; each gets n_f nails and c_f clips. The N_p perimeter tiles get n_p and c_p. The totals are increased by the spare allowance w and rounded up.
It is a weighted count: two groups of tiles, each with its own fixing rate.
Sense check: 1016 tiles with 200 perimeter tiles, one nail each and one clip on each perimeter tile, gives 1016 nails and 200 clips.
Watch out: the fixing rates must come from a BS 5534 wind-uplift assessment or the manufacturer's fixing specification for your site, not a rule of thumb.
Counts nails and clips from the fixing specification: one rate for the main area of the roof and another for perimeter tiles, which BS 5534 requires to be fixed twice.
Enter your values to see the result.
Good to know
Under BS 5534 every single-lap tile must be mechanically fixed (at least nailed), with perimeter tiles at eaves, verges and ridge given two fixings (for example nail plus clip); a wind-uplift fixing calculation decides whether main-area tiles also need clips. Plain tiles: each tile in every fifth course twice nailed (average 0.4 nails per tile) with perimeter tiles, including the first two eaves courses and last two ridge courses, twice nailed. Natural slates are normally twice nailed; fibre cement slates take 2 nails and 1 disc rivet. Get the manufacturer’s fixing specification for the site.
Common mistake
Ordering one fixing per tile on a plain-tile or perimeter-heavy roof. Perimeter tiles need two fixings each.
Limits
Counts only. The fixing specification (number and type of fixings, nail length and gauge) depends on wind zone, height, pitch and exposure and comes from the manufacturer’s BS 5534 calculation.
Sources
- Marley: What are the fixing requirements of BS 5534? (all single-lap, ridge and hip tiles mechanically fixed; perimeter tiles fixed twice)
- Wienerberger (Sandtoft): BS 5534 roof tile fixing requirements (plain tiles every fifth course twice nailed, perimeter two fixings)
- Marley Rivendale fibre cement slate fitting instructions (gauge formula, 5 mm gap, 2 nails + 1 disc rivet per slate, coverage and weight table)
- NHBC Standards 7.2.19 Fixing tiles and slates
- BS 5534:2014+A2:2018 Slating and tiling for pitched roofs and vertical cladding. Code of practice (BSI)
Results are calculations from the published methods and figures shown, and depend on the data you enter. Follow the roof covering manufacturer’s fixing specification, BS 5534, BS 8000-6, BS 6229, the Lead Sheet Training Academy guidance and Building Regulations. Wind uplift and structural design need a competent designer.