Anyone who has looked up at an old slate roof still shedding rain after a century understands why people choose it. It is also not the right covering for every building. It asks for a sound structure underneath, a roofer who knows how to fix it, and a budget that can carry a higher up-front price than concrete tile.
This guide weighs both sides. It covers life, appearance, weather and fire resistance, weight, cost and the skills needed for repair, using published figures where they exist and plain observation where they do not. It does not rank slate against other coverings on price alone, and it does not go into lifespan in depth: our page on how long a slate roof lasts does that. The service overview is on our slate roofing page.
The advantage everyone cites: a long working life
The strongest argument for natural slate is how long it stays on the roof. MyBuilder's slate roof cost guide, updated 21 August 2026, gives natural slate 80 to 100 years or more, against 40 to 60 for clay tiles and 30 to 50 for concrete. Synthetic and fibre-cement slate is put at 30 to 50 years in the same guide. Sources do disagree about clay and concrete: Marley, a tile maker, cites a minimum life expectancy of 60 years for clay, and CORC's guidance gives clay 100 years or more if well maintained. The ordering is nonetheless consistent, with natural slate at or near the top.
Long life matters for two reasons. The covering is the most expensive part of a re-roof to replace, so one that lasts through several generations of owners spreads its price very thinly. And a roof that does not need re-covering is a roof whose battens, underlay and fixings do not need renewing on the same timetable.
The caveat that goes with it
The stone is rarely what fails first. On older roofs it is usually the fixing, the nail through the slate, that gives up, and slates then slip while still perfectly sound. A quoted lifespan is therefore a ceiling for the slate itself, not a promise for the roof. Typical ranges rely on exposure, workmanship and upkeep, and none of them is a guarantee.
Look and finish: what slate gives a house
Slate has a flat, fine-grained surface and a crisp edge line that no moulded tile quite copies. Courses run true across a slope, and the colour is the colour of the stone, not a surface coating that can fade. Roofs in blue-grey and dark grey tones sit well against both stone and brick, and slate has been the covering on many Victorian and Edwardian houses for the simple reason that it was available and suited the period.
On older houses, it is often the right answer
For a building that was slated originally, slate is the covering a conservation officer is most likely to expect to see go back. Stroud District has 41 conservation areas, and listed buildings are protected throughout, whatever their grade, so a change of covering can need consent. Putting slate back where slate was is the simplest way to keep the street scene intact, as well as the simplest to explain to the planning team.
The drawback on appearance
A slate roof is uniform by design, which some owners find severe next to stone or clay. On a Cotswold stone house, slate is the wrong material: stone stays stone, and our page on Cotswold stone roofing covers that. Look is a matter of taste, and a sample held against your walls settles it faster than description.
Weather and fire resistance
Slate is a dense stone that takes up very little water, and it does not rot, rust or burn. Frost, sun and years of rain wear it slowly, which is why so many roofs survive. Fire performance is a quality of the stone rather than of any coating. Fire rating also enters the rules: a change to a covering that behaves quite differently in a fire counts, for the Planning Portal, as a reason to seek approval, so a move away from slate is a question for building control.
Where the weathering sits in practice
Rain is kept out by the lap between slates, not by the slate alone. Each slate overlaps the courses below by a measured headlap, and that headlap needs to suit the slate size and the pitch. Cupa Pizarras, a slate producer, publishes the headlap for a 500 mm by 300 mm slate: 115 mm at 20°, 105 mm at 22.5° and 95 mm at 25°, all for moderate exposure. BS 5534:2014 sets 20° as the lowest pitch for natural slate in those conditions.
The drawback on shallow roofs
That minimum pitch is a real limit. A roof below it cannot simply be slated, and Cupa adds that hook fixings should not go on a pitch below 25°. Low-pitched extensions, porches and dormer cheeks often need a different covering or a different detail, such as lead. We check the pitch at survey before suggesting slate at all.
Weight and what the structure has to carry
A covering is also a load, and slate is a heavy one compared with some lighter alternatives. The weight per square metre varies with the slate's thickness and size, so there is no single figure to rely on. The data sheet for the exact slate gives it.
Why it matters is spelled out in the regulations. Two government documents set the 15% line. For the Planning Portal, approval is needed once a new covering weighs 15 per cent more, or beyond; Approved Document A calls a rise above 15% significant, and strengthening follows where the structure cannot sustain it. Where the new covering is much heavier, the Portal itself suggests asking a structural engineer or surveyor before starting.
When slate replaces something lighter
Swapping a lightweight roof for slate is a decision that should start with the timbers. Old rafters may be undersized or sagging, and a roof that has carried a light covering for decades can show it once a heavier one goes on. We look at the loft from underneath at survey and say if a structural check is needed first.
When slate replaces slate
Like-for-like slate over a sound structure raises no new load question, which is part of why we re-slate in slate. Where a different thickness is chosen, we compare weights and tell you the result.
Cost: a higher price at the start
Slate is not the economy option. MyBuilder puts a slate re-roof at £100 to £180 per m² installed, with Welsh at £140 to £180 and Spanish at £100 to £130. Checkatrade's full re-roof guide, updated October 2026, gives £110 to £260 per m² for a gable roof and £145 to £285 for a hipped one, across all coverings and excluding VAT. Slate therefore sits in the middle to upper part of the range for pitched roofs. A re-slate also commonly needs scaffold, which MyBuilder prices at about £1,125 for a re-roof. Disposal of the old covering is a further line, which the same guide gives as £100 to £1,000 depending on volume. Neither is peculiar to slate, but both belong in the comparison when you set a slate quote beside a quote for a lighter covering that is quicker to lay.
Setting price against life
A fairer comparison is cost per year of service. A covering that costs more but lasts two or three times as long can cost less over the life of the house. That argument holds only if the roof is kept and the building is staying put. For a house you plan to sell soon, the saving arrives for someone else. Our re-slating guide follows what a full job involves.
Slate costs more on day one and less per year if the roof is kept and maintained. Whether that suits you depends on how long you expect to own the house.
Every price above is a national figure from a third-party guide. Ours follows the visit, in writing, so any part of it can be queried.
Repair skills and upkeep
Slate is repairable, which is another advantage: a cracked or slipped slate can be replaced individually without disturbing the whole roof. MyBuilder prices a single slate repair at £60 to £120, and five to ten slates at £150 to £350. A slater's day rate is quoted at £200 to £300.
The drawback on skills
Slate work is slower and less forgiving than fixing machine-made tiles. Each slate is a thin sheet of stone, so a dropped tool, a heavy boot or a ladder resting in the wrong place can crack several at once, and a cracked slate under another is hard to see from the ground. Slates are nailed or hooked individually, cut to fit at valleys, hips and abutments, and can crack if walked on or hit. A roofer unused to slate can do more harm than good, particularly with tools and weight on the surface. We look at the nail fixings first when slates are slipping, since fatigued nails are one of the first things to check.
Upkeep
Slate does not need sealing or painting, but gutters, flashings and valleys do need looking at. Lead flashing can last more than 80 years when correctly fitted, according to MyJobQuote, but the junctions around it need checking. Moss can build up on shaded slopes; MyBuilder prices slate roof cleaning at £500 to £1,000, adding that jet-washing can mark fragile tiles. Our slate roof maintenance guide sets out what to do and how often.
Does slate suit your house?
Pulling the threads together, slate tends to suit a house when several of these hold.
- The roof was slated originally, or sits in a street of slate roofs.
- The pitch is comfortably above the 20° minimum, with no shallow extension slopes.
- The timbers are sound or can be made sound, so the load is not a problem.
- You plan to keep the house for many years.
- The budget can stretch to a higher start-up cost.
It suits less well on a stone-tiled Cotswold cottage, a very shallow roof, a structure that cannot take the weight, or a short ownership horizon.
How we help you decide
At survey we measure the pitch, check the timbers from the loft, photograph the existing covering and note any listing or conservation constraint. The quote covers the slate options. Our workmanship guarantee lasts 10 years in writing. We remove the waste and leave the site in order.