Search for what a roof costs and you'll find plenty of numbers. Most of them are per-square-metre figures that price the one variable that's easy to measure and ignore the ones that actually move the total.
We're not going to add another number to that pile. What we can do is tell you precisely what changes the price, so that when you do get quotes — ours or anyone's — you can see what you're paying for.
The things that move the price
1. Area
Size moves the price, no question — but it's a weaker guide than people expect, which is exactly why per-square-metre figures mislead. A small roof with three chimneys, a valley and no rear access can cost more than a larger, simpler one.
Pitch comes up less often than you'd think. It becomes a cost of its own only where a roof was pitched wrongly in the first place and the pitch has to be rebuilt to put it right. That isn't something we run into regularly.
2. Getting to it safely
Access is one of the biggest swings, and one people rarely think about. A detached house with a clear drive on all four sides is straightforward. A mid-terrace with no rear access, a conservatory underneath, or a roof over a public footpath is a different scaffold job entirely — and scaffolding is a real cost, not a line item to pad a quote with.
3. What's underneath the covering
This is the one that can't be fully known up front, and the honest way to handle it is to say so.
On a flat roof the deck decides the most. A sound timber deck means an overlay is possible, and an overlay is the cheaper job — but it doesn't make it automatic. Often the covering has failed badly enough that replacing it is the better call anyway, and sometimes that's your decision rather than ours. A water-damaged or failing deck settles the question: the whole thing comes off.
On a pitched roof more things are in play than on a flat one. Water getting in. A tiling membrane that's failed — or was never there at all, which is common enough on older houses. A roof that was laid out wrong to begin with. Slate that's started to shale, meaning it's splintering apart in layers. The timbers matter too, and worth knowing: individual joists can be replaced rather than the whole roof structure, so it isn't the wholesale job people fear.
Where we can see it, we tell you on the visit. Where we genuinely can't, the quote carries a priced contingency, so the number is agreed before work starts rather than discovered during it.
4. Insulation
Whether the roof needs insulation, and how much, depends on what sits underneath it — and it lands on the total either way. A flat roof over non-habitable space, a garage being the usual example, often needs none at all. Habitable space underneath is a different build-up and a different figure. This applies to pitched and flat roofs alike.
5. Strip off, or overlay
Directly downstream of the above, and a large difference in both labour and waste. We don't charge for a strip-off a roof doesn't need.
6. The material
The biggest single multiplier on a pitched roof. Natural slate and concrete interlocking tile are not close on price. Clay sits between them. Neither is "better" in the abstract — what's right depends on the building, and on a period property or one in a conservation area the choice may be narrowed for you.
7. Reusing what's there
Reclaiming existing slate saves materials and costs labour. See the question below — it's often slower, not cheaper.
8. Number of layers, on a flat roof
A three-layer built-up bitumen system is not the same job as a two-layer overlay, and a warm deck with insulation above the deck is more work again than a cold deck. As a reference point, a 30 sq m garage roof in a three-layer system is about two days' work.
9. Ridge and gable
Dry systems — mechanically fixed and ventilated — are what we'd put on almost every roof, and what current standards favour. A traditional wet ridge bedded in mortar is the right call on a listed building or one inside a conservation area, and is sometimes what a specification asks for.
10. Chimneys, valleys and lead work
Detailing is where roofs leak and where the skilled time goes. Two chimney stacks, a valley and new lead flashings add real hours. A simple gable-to-gable roof with nothing coming through it doesn't.
11. Listed and conservation constraints
On a listed building we obtain a product specification before work starts, so what goes on the roof is what meets the requirements. In a conservation area no specification is required, but sourcing a close match takes time. Either way it narrows material choice, which affects cost.
12. The guarantee the system carries
Our workmanship guarantee on a re-roof runs from ten to twenty-five years, depending on the materials and system used. That range isn't marketing — it's the actual trade-off. A longer term reflects a specification built to last longer, and the figure for your roof is confirmed in your written quote before you commit.
This is the useful way to think about roofing cost: not cheap versus expensive, but upfront cost against how long it lasts.
What we do instead of a price list
Come and look, for free. Tell you the findings and the sensible options on site — sometimes there's more than one system that would work, and they carry different guarantee terms. Then a written quote within seven days, with payment terms, full T&Cs and the guarantee written in.
Quotes for homeowners include VAT. Commercial quotes usually show it separately. Either way the quote states which, in writing.
Ask us to come and look — or send a photo first, if you'd rather start there.