The four main covering materials for a pitched roof in the UK are natural slate, clay tiles, concrete tiles and fibre-cement slate. Each performs differently in terms of lifespan, structural load, minimum pitch and planning status, and the right choice depends on the building's structure, its location and any planning constraints that apply to it. This article sets out what the key differences are, what regulations govern the installation and what tradespeople and property owners need to check before committing to a material.
Natural Slate
Lifespan and performance. Natural slate is the longest-lasting and most prestigious covering. Welsh slate routinely serves 100 years and more. When a slate roof fails, it is usually nail sickness or rotten battens rather than the slate itself, which is why so much slate gets reclaimed and reused.
Weight. Natural slate is comparatively light, which can matter on older structures. This is a meaningful advantage when re-roofing a period property whose timbers were not designed for heavier coverings.
Minimum pitch. Natural slate requires a minimum pitch that varies depending on slate size and head lap. BS 5534, the Code of Practice for Slating and Tiling, governs these requirements.
Installation. The catch is price: slate costs the most to supply and is slower and more skilled to lay, as each slate is holed and nailed individually. Only engage a roofer with demonstrable slate experience - ask to see examples of previous work and confirm they work to BS 5534.
Clay Tiles
Lifespan and performance. Clay tiles have a long lifespan, with machine-made versions at the lower end and handmade at the top. Clay's colour is fired all the way through rather than coated on, so it does not fade; many clay roofs look better at 40 years than they did new as they weather and mellow.
Weight. Clay tiles are heavier than natural slate depending on profile. A structural check is advisable before switching from slate to clay on an older building.
Minimum pitch. Clay tiles require a minimum pitch that varies by tile type. Manufacturer specifications and local exposure zone - as defined under BS 5534 - may require a steeper angle.
Where clay is typical. Clay is the traditional choice across much of Kent and the South East. It is also strongly favoured by conservation officers and listed building authorities, where handmade or reclaimed clay is often the only acceptable option.
Concrete Tiles
Lifespan and performance. Concrete tiles have a finite lifespan before the surface erodes and the tiles become porous and brittle. The surface pigment can fade or grow moss over time, which affects appearance before structural integrity is threatened.
Weight. A concrete tile roof is heavy, and the roof timbers must be designed to carry the load. Swapping a slate roof for concrete tiles can more than double the dead load on the structure , so a structural engineer's assessment is essential in that scenario.
Minimum pitch. The minimum roof pitch for standard concrete interlocking tiles varies by manufacturer and tile type. As with other materials, BS 5534 requires the pitch to reflect the local exposure zone, and manufacturers' fixing specifications may require a steeper pitch in areas of high wind-driven rain.
Practical advantages. Concrete is the default on most post-war UK housing for good reason: it is the cheapest per square metre, widely stocked, and every roofer can fit it. Interlocking concrete tiles lock together at the edges, so fewer tiles cover each square metre and installation is quick.
Fibre-Cement Slate
Fibre-cement slate is lightweight and has a lifespan shorter than natural slate. It is a manufactured product designed to replicate the look of natural slate at a lower supply cost and with a lighter structural load. Lightweight options like fibre-cement slates benefit retrofits and structures with limited load capacity. Colour stability is generally fair to good rather than the true permanence of fired clay or natural stone, and some conservation planning authorities will not accept fibre-cement as a substitute for natural slate. Always check with the local planning authority before specifying it on a heritage property.
Building Regulations and Minimum Standards
UK pitched roofs are governed by BS 5534:2014+A2:2018 (slating and tiling code of practice) and Building Regulations Part L (thermal) and Part C (moisture). Tile selection, batten size, fixing pattern and underlay all depend on roof pitch, exposure zone and tile or slate type.
Building Regulation Approved Document C2 requires that all tiled and slated roofs are designed and constructed to keep out wind-driven and deluge rainfall, or have a means of draining away safely any water that does enter the roof system.
On thermal performance, Building Regulations require specific U-value standards for pitched roofs to reduce heat loss and improve energy efficiency.
Building Regulations are minimum standards, not best practices. Many roofing professionals recommend pitches at least one step above the regulatory minimum to provide an extra margin of safety against wind-driven rain.
Pre-start checklist for any re-roofing project
- Check structural capacity. Confirm the roof timbers can carry the dead load of the proposed material, particularly if changing from slate to concrete or clay tile.
- Confirm planning status. Establish whether the property is listed, in a conservation area or subject to an Article 4 direction before ordering materials.
- Verify minimum pitch. Match the material to the existing roof pitch using the manufacturer's data sheet and BS 5534 exposure zone maps.
- Specify underlay and battens. BS 5534 provides comprehensive guidance for slating and tiling on pitched roofs, covering installation methods, materials, and performance requirements. This standard specifies minimum laps, fixing requirements, and ventilation provisions that must be followed to ensure weather-tight construction.
- Check U-value compliance. Ensure the build-up meets the relevant U-value target under Approved Document L.
- Use a qualified contractor. The National Federation of Roofing Contractors (NFRC) publishes a find-a-contractor service for members working to BS 5534.
Planning Rules for Roof Covering Changes
The Planning Portal, which publishes the Government's official guidance on permitted development, confirms that work to the roof of a house - for example, re-roofing - that does not materially affect its external appearance will usually not require planning permission.
In England, Wales and Scotland, replacing the covering of an existing roof with the same or similar materials is generally considered permitted development, meaning it can be carried out without needing to apply for planning permission. This covers the most common scenario: tiles or slates that are at the end of their life being replaced with equivalent tiles or slates.
However, permitted development is not a blanket right. In conservation areas, Article 4 directions often restrict changes to roof materials and coverings that would otherwise be permitted. Replacing natural slate with concrete tiles, or changing clay pantiles to interlocking concrete tiles, might need planning permission in a conservation area where the Article 4 covers roof alterations.
Listed buildings always require listed building consent for any external changes, including roof material changes. Specialist materials - handmade clay, reclaimed stone, traditional lime mortars - are usually required.
Where there is any doubt as to whether a development would be permitted development, advice should be sought from the local planning authority. To be certain that a proposed development is lawful and does not require an application for planning permission, it is possible to apply for a Lawful Development Certificate from the local authority.
If you are looking for qualified tradespeople to carry out roofing work, trade services listed on GetBrent cover roofers and related contractors across the country. For jobs in the capital, browse trade services in London, or if you are based further south-east you can find trade services in Bromley covering the surrounding area.
GetBrent connects property owners and project managers with local roofing contractors, scaffolders, skip hire firms and other trades. Search trade services near you on GetBrent to find firms that can quote for your re-roofing project - and always ask any contractor to confirm they work to BS 5534 and hold current public liability insurance before work begins.
