A pitched roof is a complex system of interlocking components. While the tiles provide the primary shield against the elements, it is the unseen fasteners that provide the critical strength and security. Selecting the correct nails, clips, and fixings is not just a matter of best practice; it is essential for ensuring a roof’s longevity, weather resistance, and compliance with British Standards.
Using the wrong fastener can lead to catastrophic failures, voided warranties, and costly repairs. This guide, based on the book co-written by the Roof Tile Association and National Federation of Roofing Contractors, The Design and Installation Guide for Roof Tiling – 1st Edition, provides a clear overview of the essential fasteners needed for a durable, compliant roofing project.
Nails for Tiles: The First Line of Defence
The primary fixing for most roof tiles is the nail. Choosing the right material and size is crucial for achieving the required holding strength and long-term durability.
Typically, clout head nails are used, and they must penetrate the roof batten by at least 15 mm. The most common diameters are 3.35 mm and 2.65 mm, with the final specification depending on wind load calculations.
Approved Nail Materials (BS 1202 & BS EN 10088-3)
The material of the nail is just as important as its size. To prevent corrosion and ensure a long service life, only approved materials should be used.
| Material | British Standard | Common Applications |
| Copper | BS 1202 | High-quality, durable fixing suitable for most environments. |
| Aluminium | BS 1202 | A common and cost-effective choice for standard applications. |
| Stainless Steel | BS EN 10088-3 | Essential for coastal, marine, or aggressive environments (Grade 304 or 316). |
| Zinc-Coated Steel | BS EN 10230-1 | Galvanised nails for use where a protective coating will not be damaged. |
In highly aggressive environments, the manufacturer may specify alternative materials, such as silicon-bronze, to prevent premature failure.
Tile Clips: Securing Against Wind Uplift
While nails provide the primary fixing, tile clips are essential for providing mechanical security against wind uplift, particularly for large format tiles. All proprietary tile clips are designed and tested by manufacturers for use with their specific tile profiles.
Important: Using third-party or generic clips that the tile manufacturer has not approved may void the roof tile warranty. Always refer to the manufacturer’s specifications and the guidance within BS 5534 for correct clip selection and installation.
Fasteners for Fittings: Ridges, Hips, and Verges
Roof fittings such as ridge, hip, and verge tiles require robust mechanical fixing to prevent dislodgement. For all mortar-bedded applications, a mechanical fixing is mandatory.
- Hip Irons: These simple but effective hooks are fixed to the base of the hip rafter to provide a secure anchor for the first hip tile.
- Fixings for Mortar-Bedded Fittings: All ridge, hip, and verge tiles must be mechanically fixed, even when bedded in mortar. The tile manufacturer typically supplies/prescribes these fixings.
- Dry-Fixed Systems: Alternatively, proprietary dry-fix systems for ridges, hips, and verges can be used. These products must meet the requirements of BS 8612 to be considered compliant.
Nails for Securing Battens: The Foundation of the Roof
The security of the entire roof covering depends on the battens being fixed correctly to the rafters. The standard fixing for this is a 65 mm long, 3.35 mm diameter round wire nail, which must achieve a minimum penetration of 40 mm into the rafter.
For areas with high wind loading, longer or improved fixings (such as ring-shank nails or screws) may be necessary. If using a mechanical nail gun, always consult the manufacturer’s guidance to ensure the fixings meet the required performance standards. For detailed guidance on calculating wind load resistance, refer to BS 5534 Annexe H7.
Flashings and Junctions: Preventing Water Ingress
Metal flashings at abutments, chimneys, and other junctions must be fixed with materials that prevent corrosion and failure.
- Fixing Lead Flashings: Use only copper or stainless steel nails. Aluminium nails must never be used to fix lead sheet, as this will cause rapid galvanic corrosion, leading to failure of the fixing.
- Nail Sizing: Nail sizes should follow the recommendations of the Lead Sheet Training Academy.
- Exposed Areas: In highly exposed locations, consider additional clipping of flashings as detailed in the Rolled Lead Sheet Manual.
Get the Complete Guide for Design and Installation
This article provides a summary of the key considerations for selecting and installing roofing fasteners. For comprehensive technical details, wind-loading calculations, and full specifications, these topics are covered in depth in the official Design and Installation Guide for Roof Tiling.
This new guide has been written and released in partnership between the RTA (Roof Tile Association) and NFRC (National Federation of Roofing Contractors) to provide the most comprehensive and up-to-date guidance for roof tiling available, covering all the information that budding tilers, and those with experience, need to know when they’re on the job.
We are currently able to offer a 25% discount for the The Design and Installation Guide for Roof Tiling, ISBN 9781032053134 using the code RTA25. Purchase the full guide here