Double-storey extensions · Brighton

Double-storey extensions in Brighton

Our double-storey extensions service covers Brighton and the rest of East Sussex. You get a fixed price in writing for the agreed specification, and one person co-ordinating the trades.

Covering Brighton

Our coverage around Brighton (BN2) also includes Hove, Rottingdean and Burgess Hill.

Homes in the South East

Many South East homes are inter-war or post-war semis and detached houses with room for rear and side extensions, while historic town centres and villages bring conservation area and listed building controls.

What is included in a double-storey extension in Brighton?

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.

  • Measured survey, design and planning drawings
  • Structural engineer’s design and calculations
  • Foundations, steelwork, brick and block walls, roof

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

What double-storey extensions typically cost. These are guide ranges; the written quote for your house replaces them.

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

Do you need permission for a double-storey extension in Brighton?

English projects need planning clearance from the local council, building regulations sign-off from building control, and party wall notices where the work is on or near a shared boundary. We prepare and manage all three.

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.

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.
  • Neighbours’ light is assessed using the 45-degree guide many councils use.

What are the steps?

  1. Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
  2. Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
  3. Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
  4. We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.

Questions about a double-storey extension in Brighton

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.

How long does a two-storey extension take?

Around 14 to 24 weeks on site, plus the planning period before that.

Do you work in Brighton?

Yes. Brighton is within our coverage for double-storey extensions, along with nearby Hove and Rottingdean.

Also covering

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

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