Flat roof extensions for homes in Doncaster
Our design and build teams take on flat roof extensions in Doncaster, from the first measured survey through planning and building control to the finished room.
- Guide price in DoncasterFrom £19,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time10–16 weeks on site
- Postcode districtsDN1, DN2, DN3, DN4, DN5

Flat roof extension prices in Doncaster
Prices below are for Doncaster, using the Yorkshire and the Humber factor of ×0.94. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Doncaster: £1,640 to £3,150 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £19,500 – £23,500 | £23,000 – £29,500 | £29,000 – £38,000 |
| 4 m × 5 m 20 m² | £32,500 – £39,000 | £38,500 – £49,000 | £48,500 – £63,000 |
| 5 m × 6 m 30 m² | £49,000 – £58,000 | £57,500 – £73,500 | £73,000 – £94,500 |
For a figure based on your own dimensions, use our guide-price tool.
Included in a typical project
- Falls and outlets designed to drain properly
- Membrane choice: single-ply, EPDM or GRP
- Lanterns or rooflights with upstands
- Parapets or edge trims and flashings to the house
- Warm-roof design with insulation above the deck
Height is often what decides a flat roof. Under first-floor windows, a pitched roof may not fit at all; a flat roof keeps the extension low while still giving a good ceiling height inside.
Will the council need to approve it?
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
The planning position for a specific Doncaster address depends on its history and any designations, which is why we check it at the first visit.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
Working in Doncaster
Postcode districts we cover around Doncaster include DN1, DN2, DN3, DN4, DN5, DN12. Neighbouring towns we cover include Adwick le Street (4 miles), Rawmarsh (10 miles), Dinnington (11 miles), Rotherham (11 miles).
Just over the West Yorkshire border, South Elmsall is about 8 miles away. Yorkshire and the Humber combines stone-built terraces in the Pennine towns with brick semis and newer estates elsewhere, so materials and roof details need matching with care.
How the project works
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Common questions in Doncaster
How long does a flat roof extension take to build in Doncaster?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.
Will my neighbours in Doncaster be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Do you cover all of Doncaster?
Yes. We cover Doncaster and the surrounding parts of South Yorkshire. Site visits are free and there is no obligation.
Can I walk on a flat roof extension?
Only for maintenance unless it is designed as a terrace. A roof terrace or balcony needs planning permission and a different structure.
Are flat roof extensions cheaper?
Usually slightly, because there is less roof structure and no tiles. Our guide range is about £1,640 to £3,150 per m² including VAT.
Book a free site visit in Doncaster
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.