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Bedroom extensions in Ashford, Surrey: design, approvals and build

Ashford, Surrey homeowners can use us for the whole bedroom extension project: survey, design, planning or permitted development checks, building regulations and the build itself.

  • Guide price in Ashford, SurreyFrom £29,000 inc VAT
  • PlanningUsually a householder application
  • Build time14–22 weeks on site
  • Postcode districtsTW15, TW16, TW18
Bedroom in an extension with a roof window and an en-suite shower room

Is a bedroom extension right for your house?

  • Homeowners who want an en-suite master bedroom
  • Multi-generational households
  • Growing families

Extensions in and around Ashford, Surrey

Site visits are available across Ashford, Surrey (TW15, TW16, TW18). We also work in nearby Staines-upon-Thames (2 miles), Sunbury-on-Thames (3 miles), Walton-on-Thames (4 miles), West Molesey (4 miles).

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.

Bedroom extension prices in Ashford, Surrey

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 Ashford, Surrey: £1,790 to £3,580 per m² including VAT, depending on specification.

SizeEssentialStandardPremium
One bedroom
12 m²
£29,000 – £35,500£29,000 – £38,000£32,000 – £43,500
Bedroom and en-suite
18 m²
£32,000 – £39,500£38,000 – £49,500£48,000 – £65,000
Two rooms
30 m²
£53,500 – £66,000£63,500 – £82,500£80,500 – £108,000

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

Planning rules that apply in Ashford, Surrey

In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.

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 regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.

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).

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

    A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.

  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

    Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.

Your questions about a bedroom extension in Ashford, Surrey

Do I need building regulations approval in Ashford, Surrey?

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

How long does a bedroom extension take to build in Ashford, Surrey?

On site, typically 14 to 22 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.

Will my neighbours in Ashford, Surrey 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.

Will a new bedroom need planning permission?

Upstairs additions usually do. Ground-floor rooms may fall within permitted development, depending on size and position.

How much does a bedroom extension cost?

Our guide range is about £1,790 to £3,580 per m² including VAT. A bedroom with an en-suite of about 18 m² is typically £38,000 to £49,500 at standard spec, depending on whether it is part of a larger two-storey build.

Book a free site visit in Ashford, Surrey

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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