Clay and concrete roof tiles are the two dominant pitched roof coverings in UK residential construction. Both shed water effectively, both are available in profiles that approximate traditional British roofscapes, and both comply with BS 5534:2014+A2:2018 (the standard for slating and tiling). But they differ significantly in cost, lifespan, weight, minimum pitch, and visual quality — differences that matter when re-roofing an existing house, extending a property in a conservation area, or specifying a new-build in a planning-sensitive context.
Key Differences at a Glance
| Property | Clay tiles | Concrete tiles |
|---|---|---|
| Typical lifespan | 60–100+ years | 40–60 years |
| Weight (kg/m²) | 40–75 kg/m² (plain tiles) | 42–80 kg/m² (interlocking) |
| Typical minimum pitch | 35° (plain clay); 17.5° (single lap) | 17.5° (interlocking); 22.5° (plain) |
| Installed cost (£/m²) | £35–£70 | £25–£50 |
| Frost resistance (EN 539-2) | Class F2 (frost-resistant required for UK) | Not applicable; cement-based |
| Colour stability | Excellent (fired-in) | Fades over 15–25 years |
| Conservation area acceptance | Generally acceptable | Often refused; check LPA guidance |
Clay Roof Tiles
Clay tiles are manufactured from natural clay, extruded or pressed into shape, then fired in a kiln at 900–1,100°C. The firing process vitrifies the surface, making it inherently dense, waterproof, and dimensionally stable. The colour is fired into the body of the tile and does not fade — a 50-year-old clay tile looks much the same as a new one, which is why they work so well in conservation areas and for matching original roofscapes.
Types of Clay Tile
Plain clay tiles are the traditional small-format tile (265 × 165 mm is the most common size) laid in a double-lap pattern — each tile overlaps the one two courses below it, creating a three-layer covering at every point. This gives excellent weather resistance but uses many tiles (approximately 60 tiles/m²), making labour cost higher. Plain tiles require a minimum pitch of 35° for most profiles, though machine-made plain tiles with nibs can go to 30° in sheltered locations.
Interlocking single-lap clay tiles (also called pantiles, roman, or double-roman profiles) have a moulded edge that locks into the adjacent tile, requiring only single-lap in the head lap direction. This halves the number of tiles per m² and reduces minimum pitch to 17.5–22.5° depending on profile and exposure. Examples include profiles resembling the S-shaped pantile or the half-round roman tile. These are typically more expensive per tile but faster to lay.
Specialist clay tiles include valley tiles, hip tiles, ridge tiles, and eaves ventilation tiles. A well-detailed clay roof also uses clay fittings at all these junctions — critical for long-term watertightness and visual consistency.
Relevant standards:
- BS EN 1304:2013 — clay roofing tiles and fittings
- BS EN 539-2:2007 — determination of frost resistance
- Clay tiles for UK use must achieve Class F2 (frost-resistant), which all reputable UK suppliers stock as standard
Clay Tile Performance
The longevity advantage of clay is largely attributed to the absence of carbonation or alkaline leaching that affects concrete. Clay does not shrink, does not effloresce, and does not absorb significant moisture once fired. Where clay roofs fail, the cause is almost always degraded fixings (nails, torching, or mortar bedding), failed underlay, or ridge/hip detail failure — not the tiles themselves.
Concrete Roof Tiles
Concrete tiles are manufactured from portland cement, sand, aggregate, and pigment, pressed under high pressure into moulds and cured. They are generally interlocking (single-lap) and have been the dominant new-build roofing material in the UK since the 1960s.
Types of Concrete Tile
Concrete interlocking tiles (e.g. 430 × 380 mm or similar large-format) are the most common type. They cover approximately 10 tiles/m² and can be laid at pitches as low as 17.5° with the correct head lap and underlay specification. They are suitable for most UK exposure zones at pitches of 22.5° and above.
Concrete plain tiles mimic the size and profile of traditional clay plain tiles (265 × 165 mm) but at lower cost. They are used where the pitch or planning context requires a plain tile appearance but budget is constrained. Lifespan is 30–50 years, shorter than clay plain tiles.
Concrete granular or slate-effect tiles have a crushed stone or granular surface texture that gives a rougher, darker appearance resembling fibre cement or slate from a distance.
Concrete Tile Degradation
The principal weakness of concrete tiles is colour fading and surface carbonation. The iron oxide pigments used for colouring are generally stable, but the cement matrix carbonates and the algae/lichen colonisation that all roof tiles attract appears differently on concrete versus clay. Many concrete tiles develop a patchy appearance after 20–30 years that is difficult to restore without recoating. Some tiles manufactured in the 1970s–1990s also develop surface delamination as the surface layer spalls.
Relevant standards:
- BS EN 490:2011 — concrete roofing tiles and fittings
- BS EN 491:2011 — test methods for concrete tiles
- BS 5534:2014+A2:2018 — slating and tiling (applies to both clay and concrete)
Weight and Structural Implications
Both clay and concrete tiles impose significant dead loads on the roof structure. For an existing roof being re-tiled, the rafter and ceiling joist sizes must be checked against BS EN 1995-1-1 (Eurocode 5) or the TRADA span tables to confirm they can carry the tile weight. Plain clay tiles at 75 kg/m² loading plus sarking and battens is a heavier load than many older rafter sections were sized for.
If replacing concrete interlocking tiles (which may have been lighter) with plain clay tiles, a structural check is advisable. Some reroofing jobs require sister-rafting or new structural elements as a result.
Minimum Pitch and Exposure
Pitch and exposure zone determine what head lap (the overlap between successive courses) is required to maintain weather resistance. BS 5534 requires the designer or tiler to check the manufacturer’s pitch/lap/exposure tables — “minimum pitch” quoted by manufacturers assumes a standard exposure zone; in severe exposure areas (west-facing roofs in Wales, Northern Ireland, NW Scotland), minimum pitch increases by 2.5–5° or head lap increases.
| Tile type | Minimum pitch (standard exposure) | Minimum pitch (severe exposure) |
|---|---|---|
| Clay plain tile | 35° | 40° |
| Clay interlocking (single lap) | 17.5° | 22.5° |
| Concrete interlocking | 17.5° | 22.5° |
| Concrete plain tile | 30° | 35° |
For pitches below these minima, specialist low-pitch systems (fibre cement, metal, or membrane) are required.
Cost Per m² Installed (2026, England)
| Tile type | Material cost (£/m²) | Installed cost (£/m²) |
|---|---|---|
| Clay plain tile (standard) | £18–£35 | £40–£70 |
| Clay interlocking | £15–£28 | £35–£60 |
| Concrete interlocking (standard) | £8–£15 | £25–£45 |
| Concrete plain tile | £10–£18 | £28–£50 |
Installed costs include new underlay (breathable felt membrane to BS 5534), treated SW battens (25 × 50 mm or 38 × 25 mm), fixings, ridge tiles in mortar or dry-fix system, and hip/valley fittings. Scaffold is additional (typically £1,500–£4,000 for a standard semi-detached).
Which to Choose?
Choose clay when:
- The property is in a conservation area or Article 4 Direction area requiring traditional materials (check with the Local Planning Authority — LPAs routinely refuse concrete plain tiles as a like-for-like replacement for clay)
- You are matching an existing clay roof — colour, texture, and profile need to be consistent
- You want a 60–100 year material life without periodic re-colouring or treatment
- The project is a high-spec new-build or refurbishment where quality and longevity justify the premium
Choose concrete when:
- Budget is the primary driver on a standard extension or new-build in a non-sensitive context
- The pitch is 17.5–30° and a large-format interlocking tile is needed
- The roof area is large and the cost saving is material (£10–£20/m² over clay on 250 m² is £2,500–£5,000)
- The design life requirement is 40–50 years and re-roofing in that timeframe is acceptable
[!note] Dry-fix vs mortar at ridge and hips Modern BS 5534:2014 guidance strongly recommends dry-fix mechanical ridge and hip systems over traditional mortar bedding. Mortar-bedded ridge tiles are a leading cause of roof failures in the UK — mortar cracks, falls away, and allows water ingress within 15–25 years. Dry-fix systems (proprietary plastic unions and mortar-free caps) are more expensive upfront (add £8–£15/m run of ridge) but last the life of the tile.
UK Standards Summary
- BS 5534:2014+A2:2018 — code of practice for slating and tiling (the primary fixing and detailing standard for all pitched roofs)
- BS EN 1304:2013 — clay roofing tiles and fittings
- BS EN 539-2:2007 — clay tiles frost resistance testing
- BS EN 490:2011 — concrete roofing tiles and fittings
- BS EN 491:2011 — test methods for concrete roofing tiles
- Building Regs Approved Document A — structural loading; rafter/ceiling joist sizing
- Building Regs Approved Document C — weather resistance
- Planning Policy (NPPF) — heritage and conservation area considerations for material choice
