Double-storey extensions in Henley-on-Thames

Covering Henley-on-Thames

We work in Henley-on-Thames (RG9) and the places around it, including Reading, Maidenhead and Wokingham.

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 goes into a double-storey extension?

Two-storey work has to sit comfortably with the house and the neighbours, so most of the design effort goes into the roofline, window positions and how the new first floor connects to the landing. We handle the planning application, the structural design and the building control process, then build, roof and finish both floors.

Measured survey, design and planning drawings
Structural engineer’s design and calculations
Windows, insulation, plastering, electrics and plumbing

What will a double-storey extension cost?

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 extensions	Guide 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

What approvals does a double-storey extension need in England?

Projects in England go through two separate checks. Planning (or confirmation that the work is permitted development) comes from the district, borough or unitary council, and building regulations approval comes from the council’s building control team or a registered building control approver. Where work touches a shared wall or digs near a neighbour’s foundations, the Party Wall etc. Act 1996 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.

What can affect a double-storey extension?

The new roof is tied into the old one, so roof tiles and ridge details need to match.
The first-floor link can mean moving a bathroom or reshaping the landing.

What are the steps?

Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.

Your questions answered

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.

Is a two-storey extension better value than a single-storey one?

Per square metre, usually yes, because the foundations and roof serve two floors of space.

Can you visit a house in Henley-on-Thames to quote?

Yes. After a short call we arrange a site visit to measure up and agree what the design needs to do, then send a written price.

Double-storey extensions in nearby towns

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