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Flat roof extensions for homes in New Malden

New Malden homeowners can use us for the whole flat roof extension project: survey, design, planning or permitted development checks, building regulations and the build itself.

  • Guide price in New MaldenFrom £27,000 inc VAT
  • PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
  • Build time10–16 weeks on site
  • Postcode districtsKT1, KT2, KT3, KT4, KT5
Flat roof of an extension with a membrane finish, a roof lantern and flat rooflights

Local to New Malden

Across KT1, KT2, KT3, KT4, KT5, SW20, we can visit, measure and advise. Nearby, we also take on projects in Worcester Park (2 miles), Surbiton (2 miles), Morden (3 miles), Wimbledon (3 miles).

For homes towards Surrey, Ewell is around 4 miles away. In London, space is at a premium and gardens are often short, so side returns, wraparounds and carefully planned rear extensions tend to make the most of every metre.

Planning and approvals in New Malden

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 New Malden address depends on its history and any designations, which is why we check it at the first visit.

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.

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).

What is included

  • Parapets or edge trims and flashings to the house
  • Lanterns or rooflights with upstands
  • Falls and outlets designed to drain properly
  • Membrane choice: single-ply, EPDM or GRP

Flat roof extension prices in New Malden

For New Malden we adjust our national guide rates by ×1.3, the factor we use for London. Figures include VAT; your written quote after the survey replaces them.

Typical rates in New Malden: £2,280 to £4,360 per m² including VAT, depending on specification.

SizeEssentialStandardPremium
3 m × 4 m
12 m²
£27,000 – £32,000£31,500 – £41,000£40,500 – £52,500
4 m × 5 m
20 m²
£45,500 – £53,500£53,000 – £68,000£67,500 – £87,500
5 m × 6 m
30 m²
£68,000 – £80,000£79,500 – £101,500£101,000 – £131,000

For a figure based on your own dimensions, use our guide-price tool.

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

    First, a site visit: we look at the house, garden, access and drains and listen to what you need.

  2. Design and approvals

    Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.

  3. Fixed written price

    With the design and specification agreed, you get a fixed written price and a start date.

  4. Build and sign-off

    Work is carried out to the agreed programme, inspected by building control and signed off at the end.

Common questions in New Malden

Do I need building regulations approval in New Malden?

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

Who do I contract with for a flat roof extension in New Malden?

Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.

Do you cover all of New Malden?

Yes. We cover New Malden and the surrounding parts of Greater London. 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 £2,280 to £4,360 per m² including VAT.

Book a free site visit in New Malden

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

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