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Flat roof extensions across East Molesey

If you live in East Molesey and want more space without moving, a flat roof extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.

  • Guide price in East MoleseyFrom £23,500 inc VAT
  • PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
  • Build time10–16 weeks on site
  • Postcode districtsKT7, KT8
Flat roof of an extension with a membrane finish, a roof lantern and flat rooflights

Planning rules that apply in East Molesey

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.

Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.

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).

How much does a flat roof extension cost in East Molesey?

For East Molesey we adjust our national guide rates by ×1.12, the factor we use for South East England. Figures include VAT; your written quote after the survey replaces them.

Typical rates in East Molesey: £1,960 to £3,750 per m² including VAT, depending on specification.

SizeEssentialStandardPremium
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.

Working in East Molesey

Site visits are available across East Molesey (KT7, KT8). The same team covers West Molesey (1 mile), Esher (2 miles), Walton-on-Thames (3 miles), Sunbury-on-Thames (3 miles), all within easy reach.

For homes towards Greater London, Hampton is around 1 mile away. 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.

Included in a typical project

  • 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
  • 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.

From first visit to completion

Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.

  1. Free site visit

    It starts with a visit to your house to measure, check access and talk through ideas and budget.

  2. Design and approvals

    Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.

  3. Fixed written price

    We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.

  4. Build and sign-off

    We build it with one project manager, book the building control inspections and hand over the completion certificate.

Common questions in East Molesey

Do I need building regulations approval in East Molesey?

Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.

Will my neighbours in East Molesey 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.

How long does a flat roof extension take to build in East Molesey?

On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.

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 £1,960 to £3,750 per m² including VAT.

Book a free site visit in East Molesey

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 .

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