Slate vs Tile: Choosing a Covering for a North East Roof

Real slate is split stone, and it is the longest lived covering you can put on a house. Welsh and Spanish slates in good condition regularly exceed eighty years, and on many local terraces the original slate has outlasted the nails holding it several times over.

It looks right on period property in a way nothing else quite matches, because the slight variation in thickness and colour catches the light. It also suits steeper pitches and is happy down to around 22 degrees with the right headlap.

The cost is the drawback. Material is expensive and it is slower to fix because every slate is individually nailed and each course is set out by hand. Expect a slate roof to cost 30 to 60 per cent more than concrete tile on the same house.

Clay is fired earth, and its great virtue is that the colour goes all the way through and never fades. A clay roof at fifty years old looks like a clay roof, weathered but not tired.

Plain clay tiles give a fine grained traditional appearance suited to older houses. Clay pantiles, with their distinctive S profile, are part of the North East vernacular and appear across older coastal and rural properties.

Clay sits between slate and concrete on price. Modern clay is frost resistant and well suited to this climate, and a good clay roof should give sixty years or more.

Concrete interlocking tiles are the workhorse of British roofing and cover the vast majority of post-war housing. They are large, they interlock so fewer are needed per square metre, and they go on fast, which is why they are much cheaper installed.

The honest weakness is appearance over time. Concrete tiles are coloured with a surface pigment that gradually erodes, so a thirty year old concrete roof looks grey and chalky compared with a new one. Structurally it may have decades left.

Modern through-coloured and granule-faced tiles have improved this considerably. On a standard semi or estate house, concrete is almost always the right value decision, and the range of profiles now includes convincing slate-effect options.

This is the technical constraint people forget. Natural slate is heavy per square metre, and so are plain clay tiles because you need so many of them. Large format concrete interlocking tiles are lighter per square metre than either.

If you are moving from concrete interlocking to natural slate or plain tile, the roof structure needs checking, because you may be adding significant load to rafters designed for something lighter.

Going the other way, from slate to a lightweight tile, is structurally easy but changes the look of the house, and on a terrace where every other roof is slate it can look out of place.

In a conservation area or on a listed building, you will normally be required to match the existing covering. That can mean natural slate rather than a slate-effect substitute, and it is worth checking with the local authority before pricing anything.

Even outside those designations, a terrace reads as one roof from the street. Putting a modern grey concrete tile into a run of Welsh slate is legal and looks wrong, and it can affect saleability.

Reclaimed slate is an option for matching, and we source it where it makes sense. It must be sorted and graded properly, because reclaimed slate with old nail holes at the wrong height is a false economy.

Period terrace or a conservation area: natural slate, or a high quality fibre cement slate where budget genuinely will not stretch and the setting permits it.

Older property with a pantile or clay character: clay, matched to the existing profile.

Post-war semi, detached or estate house: concrete interlocking, with a good through-coloured tile so it ages well.

Whichever you choose, the underlay, battens, fixings and detail work matter as much as the covering. A cheap installation of an expensive slate will fail before a careful installation of a modest tile.