Flat roof cost estimator
Measure your roof, choose the work you need, and get an honest guide price range for a premium single-ply flat roof — confirmed with a free, no-obligation survey.
Your guide price in under a minute
A professionally installed single-ply flat roof typically falls around £90–£150 per m². This tool turns your measurements into a realistic guide range — the exact figure always comes from a free survey and a fixed written quote.
What does your roof need?
Not sure? Pick the closest — the survey confirms the right approach either way.
Your measurements
In metres, to the outer edges. Odd shape? Add a section per rectangle — how to measure.
How big is the problem?
Options
That’s exactly what the free survey is for
Joel will inspect the roof, tell you honestly whether it needs a repair, a re-cover or a full replacement, and give you a fixed written quote — no obligation, nothing to pay.
Guide range including materials and labour — confirmed by a free survey.
| Item | Guide range |
|---|
Get your exact fixed quote
Send your details and this estimate to Joel — he’ll arrange a free survey and a fixed written quotation, backed by our 20-year workmanship warranty.
How to measure your flat roof
You only need two numbers per rectangle — and you never need to climb on the roof to get them.
Simple rectangle
Measure the longest edge (length) and the widest edge (width) in metres, to the outside of any upstands or edge trims. Multiply them together — that’s your area.
L-shapes & odd shapes
Split the roof into rectangles, measure each one length × width, and add them together. In the estimator, just use “add another section” for each rectangle.
- Stay off the roof. Measure from the ground along the walls below, pace it out, use architect’s drawings, or check your property on Google Earth — a metre or so out is fine for a guide price.
- Measure to the outer edges, including any upstands, parapets and edge trims — the membrane has to cover and detail all of it.
- Round up to the nearest half metre. It’s a guide price — the survey measures it properly.
- Can’t measure it at all? Skip the tool and book a free survey — we’ll do the measuring and give you a fixed written quote.
What moves a flat roof price
Two roofs with the same area can quote differently. These are the factors the survey pins down — and why the estimator gives a range, not a single figure.
- Access & scaffolding — working height and how easily materials reach the roof.
- Condition of the deck — rotted timber or a failed substrate must be put right before any membrane goes down.
- Detailing — upstands, outlets, penetrations and edges take time to weld and finish properly.
- Insulation spec — a warm-roof build-up adds cost up front and saves it on heating ever after.
- Rooflights & extras — a lantern or skylight changes both materials and labour.
For the full pricing breakdown, see our UK flat roof cost guide.
Related guides
Questions about the estimate
How accurate is the online estimate? +
It’s an honest guide range built on typical single-ply installation rates of £90–£150 per m², plus realistic allowances for insulation, rooflights and repairs. It can’t see your access, deck condition or detailing — that’s what the free survey is for, and it’s why the final fixed quote can land above or below the range.
What could make the real price higher or lower? +
The usual movers are scaffolding and access, the condition of the deck beneath the existing covering, the amount of detailing (upstands, outlets, penetrations), the insulation specification and any rooflights. Large simple roofs often price keener per m²; small awkward ones cost more.
Is the estimate a quote? +
No — it’s a guide to help you budget and compare. Your actual price is a fixed written quotation after a free, no-obligation survey, specifying the exact membrane, insulation, detailing and warranty. The survey costs nothing and you’re under no pressure to proceed.
Does the guide price include VAT? +
Guide ranges cover materials and labour for a typical installation. Your written quotation sets out the full price line by line, so you can see exactly what you’re paying and there are no surprises on the invoice.
Why does the estimator only price single-ply PVC? +
Because that’s all we fit. A correctly welded single-ply PVC roof lasts 30–40+ years and carries our 20-year workmanship warranty on top of the manufacturer’s guarantee — we don’t believe felt or GRP offers our customers the same value, so we don’t install them.
Is there a minimum job size? +
Very small roofs carry a minimum job value, because access, setup and materials have fixed costs however small the area — the estimator builds this in automatically. Repairs are priced individually, and we’ll always tell you honestly if a repair is the better-value option.
Prefer a real price to a guide price?
Book a free, no-obligation survey and get a fixed written quotation — exact system, exact spec, no surprises.