Double-storey extensions · Maidenhead

Double-storey extensions in Maidenhead

Homeowners in Maidenhead can get double-storey extensions from one company: the design, the paperwork and the building work sit with us rather than with three separate firms.

Covering Maidenhead

Alongside Maidenhead, we also cover Slough, Windsor (6 miles to the south-east) and Beaconsfield.

Homes in the South East

The South East has a lot of 1930s and post-war semi-detached housing, well suited to rear extensions and hip-to-gable loft conversions, alongside period properties in conservation areas that need a more careful design.

What does a double-storey extension involve?

A double-storey extension adds new rooms on both the ground and first floor in one build, typically a larger kitchen or living space downstairs and an extra bedroom or bathroom above. Because the roof and foundations are shared, the cost per square metre is usually lower than a single-storey extension.

  • Householder planning application
  • Structural engineer’s design and calculations
  • Windows, insulation, plastering, electrics and plumbing

How much does a double-storey extension cost in Maidenhead?

Typical ranges for double-storey extensions. Ground conditions, access and specification move the final figure, which we fix in writing before work starts.

Double-storey extensionsGuide price incl. VAT
Standard specification£2,400 to £2,900 per m²
Good specification£2,900 to £3,400 per m²
High specification£3,400 to £3,850 per m²

How is a double-storey extension approved in Maidenhead?

In England we deal with the council’s planning team for permission or a lawful development certificate, with building control (the council or a registered building control approver) for inspections, and with neighbours under the Party Wall etc. Act 1996 where it applies.

Two-storey rear extensions can sometimes be permitted development in England (no more than 3 m deep, at least 7 m from the rear boundary, roof pitch to match), but most two-storey and all two-storey side extensions need householder planning permission. Expect around eight weeks for a decision once the application is validated.

What should I think about before starting?

  • Side extensions close to a boundary are often set back or stepped down so they do not create a terraced effect.
  • The first-floor link can mean moving a bathroom or reshaping the landing.

What happens after I enquire?

  1. Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
  2. We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
  3. Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
  4. Construction and completion. One site lead co-ordinates every trade through to the building control certificate.

Double-storey extensions: common questions

How much does a two-storey extension cost?

Typically about £2,400 to £3,850 per square metre of new floor area including VAT. A 40 m² extension across two floors is often around £100,000 to £150,000 depending on specification.

Does a two-storey extension need planning permission?

Usually yes. In England some two-storey rear extensions are permitted development, but side extensions over one storey always need planning permission.

Do you work in Maidenhead?

Yes. Maidenhead is within our coverage for double-storey extensions, along with nearby Slough and Windsor.

Other towns nearby

Learn more about double-storey extensions, or see every project we cover in Maidenhead.

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