Roofing tiles: clay, stone-coated steel and shingles

What counts as a roofing tile

In shops and searches, roofing tiles covers four different products: fired clay tiles, steel tiles faced with stone chips, long steel sheets pressed to look like tiles, and shingles — thin overlapping pieces, often of asphalt. They differ in weight, in the slope they need and in how they are fixed, which is why the choice affects the roof frame as much as the look.

Clay roof tiles: two examples by data sheet

Clay tiles come in two broad kinds: small plain tiles hung in many overlapping courses, and larger interlocking tiles that lock along their sides. Two UK makers’ data sheets show the difference:

Clay roof tiles: two examples by data sheet

	Plain clay tile — Keymer Goxhill	Interlocking clay tile — Wienerberger Modula
Tile size	265 × 165 mm	443 × 328 mm
Tiles per m²	60	9.7 (at 100 mm headlap)
Weight per tile	1.202 kg	3.89 kg
Weight as laid	72.2 kg/m²	37.8 kg/m² (at 100 mm headlap)
Minimum roof pitch	35°	17.5° at 100 mm headlap; 22.5° at 75 mm

Both makers note that clay tiles vary slightly in size from drying and firing, so the roofer checks each batch before setting the batten gauge. Headlap — how far each course overlaps the one below — changes both the minimum pitch and the weight.

Battens and fixing for clay tiles

Clay tiles hang on timber battens nailed across the rafters, and the data sheets size those too. Wienerberger asks for 38 × 25 mm battens where rafters are up to 450 mm apart and 50 × 25 mm up to 600 mm, with ring-shank, clout-head nails for the tiles; at 75 mm headlap it needs 2.8 m of batten per square metre of roof. Keymer specifies 38 × 25 mm battens for its plain tile and an aluminium nail of 38 × 3.35 mm. Wienerberger also requires its tiles to be laid and fixed to BS 5534, the British code of practice for slating and tiling.

Stone-coated steel roofing tiles

Stone-coated tiles are pressed steel panels faced with stone granules; by ALAF’s figures about two panels cover a square metre (our calculation: 5.98 ÷ 2.8). ALAF, the Tanzanian sheet maker, sells them as Lifestile in Wave, Roman and Shingle profiles. Its figures: 2.8 kg per tile, 5.98 kg per m², materials that are non-combustible, and a rating for winds up to 233 km/h; ALAF describes it as eight times lighter than clay or concrete tiles.

Decra roofing tiles, searched for by brand name, are stone-coated steel too: the maker’s Tanzania site lists Classic, Milano, Shingle, Slate, Heritage and Shake profiles and states a 50-year warranty.

Steel sheets with a tile profile

Between tiles and plain sheets sit steel roofing sheets pressed to look like rows of tiles. ALAF’s Romantile and Versatile are examples: long sheets cut to the roof’s length, coated with aluminium-zinc and painted, in gloss or textured finishes. ALAF lists what it sees as the gains of Romantile over loose tiles: one continuous length per run, so fewer joints that can leak; a light sheet that is safer to lift; quick coverage from large panels; no underlay; and a profile shaped to stop water creeping back by capillary action. It also says each sheet is inspected more than six times before dispatch. Their prices per metre are listed on the roofing sheets price page, and profiles and gauges are explained under roofing sheets.

Roof shingles and tar shingles

A shingle, in the definition of the construction glossary Kreo, is a piece of roof covering — of asphalt, wood, tile, slate or other material — laid in overlapping courses. Asphalt shingles are searched for as tar shingles too; stone-coated steel is also sold in shingle shapes, as ALAF’s and Decra’s Shingle profiles show.

Weight, pitch and the roof frame

Over a whole roof the weight gap becomes tonnes. Our calculation for a 100 m² roof: about 7.2 tonnes of Goxhill plain tiles (72.2 × 100), 3.8 tonnes of Modula interlocking tiles (37.8 × 100), and 0.6 tonnes of Lifestile (5.98 × 100). ALAF makes the point that a lighter covering allows a lighter supporting structure, and the data sheets in the table show the small plain tile also needs the steeper pitch: 35° against 17.5° for the interlocking tile. Ridges for each covering are matched to it — see ridge caps.