Flat roof extensions across Berkshire
We design and build flat roof extensions for houses in Berkshire, with a written price once the survey and design are done and one point of contact throughout.
- Guide priceFrom £23,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Towns covered11
- Site visitFree, no obligation

Towns in Berkshire
What is included
- Membrane choice: single-ply, EPDM or GRP
- Lanterns or rooflights with upstands
- Warm-roof design with insulation above the deck
- Falls and outlets designed to drain properly
- Parapets or edge trims and flashings to the house
Extensions in and around Berkshire
Towns we cover in Berkshire include Reading, Slough, Bracknell, Maidenhead, Wokingham, Newbury, Earley, Windsor. Homes across the South East range from Victorian terraces in the older town centres to large detached houses on the edges, so the right extension type varies street by street.
Planning and approvals in Berkshire
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 Berkshire 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.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
Flat roof extension prices in Berkshire
These guide figures apply our South East England adjustment (×1.12) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Berkshire: £1,960 to £3,750 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £23,500 – £28,000 | £27,500 – £35,000 | £34,500 – £45,500 |
| 4 m × 5 m 20 m² | £39,000 – £46,000 | £45,500 – £58,500 | £58,000 – £75,500 |
| 5 m × 6 m 30 m² | £58,500 – £69,000 | £68,500 – £87,500 | £87,000 – £113,000 |
For a figure based on your own dimensions, use our guide-price tool.
Our process, step by step
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
We visit your Berkshire home, measure up, talk through what you want and check the planning position.
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
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Questions people ask about flat roof extensions
Do you cover all of Berkshire?
Yes, across the whole of Berkshire. Site visits are free and there is no obligation.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Berkshire, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Will my neighbours in Berkshire 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.
Are flat roof extensions cheaper?
Usually slightly, because there is less roof structure and no tiles. Our guide range is about £1,960 to £3,750 per m² including VAT.
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.
Book a free site visit in Berkshire
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.