Flat roof extensions in Dereham
Planning a flat roof extension in Dereham? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide price in DerehamFrom £22,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time10–16 weeks on site
- Postcode districtsNR19
Guide prices for Dereham
Labour and material costs vary across the UK, so for Dereham we use our East of England factor (×1.06). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Dereham: £1,860 to £3,550 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £22,000 – £26,500 | £26,000 – £33,500 | £33,000 – £43,000 |
| 4 m × 5 m 20 m² | £37,000 – £43,500 | £43,000 – £55,500 | £55,000 – £71,500 |
| 5 m × 6 m 30 m² | £55,500 – £65,500 | £65,000 – £83,000 | £82,500 – £107,000 |
For a figure based on your own dimensions, use our guide-price tool.
What is included
- Lanterns or rooflights with upstands
- Membrane choice: single-ply, EPDM or GRP
- Parapets or edge trims and flashings to the house
- Warm-roof design with insulation above the deck
- Falls and outlets designed to drain properly
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.
Working in Dereham
We cover Dereham and the postcode districts NR19. The same team covers Wymondham (11 miles), Norwich (16 miles), Thetford (20 miles), North Walsham (22 miles), all within easy reach.
Just over the Suffolk border, Bury St Edmunds is about 32 miles away. Across the East of England many houses sit on generous plots, and single-storey and wraparound extensions are a natural fit.
Planning rules that apply in Dereham
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.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
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).
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
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.
Flat roof extension questions answered
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Dereham, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of Dereham?
Yes. We cover Dereham and the surrounding parts of Norfolk. Site visits are free and there is no obligation.
Do I need building regulations approval in Dereham?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Are flat roof extensions cheaper?
Usually slightly, because there is less roof structure and no tiles. Our guide range is about £1,860 to £3,550 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 Dereham
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.