Covering Carshalton
Alongside Carshalton, we also cover Sutton, Mitcham (2 miles to the north) and Morden.
Homes in London
Terraced houses dominate many London neighbourhoods, so most projects involve shared walls, narrow access and a party wall process. Conservation areas are widespread, and some boroughs have their own mansard and basement guidance.
What is a single-storey extension?
We design the extension around how you use the house: where the light comes from, how the new room joins the old one, and what happens to the drains and the garden. The structure is built in brick or block to match the house, finished with a flat roof and lantern or a pitched roof, then insulated, plastered and handed back ready to decorate.
- Building control application and inspections
- Foundations, drainage and structural steel
- First-fix and second-fix electrics, plastering and making good
How much should I budget for a single-storey extension?
What single-storey extensions typically cost. These are guide ranges; the written quote for your house replaces them.
| Single-storey extensions | Guide price incl. VAT |
|---|---|
| Standard specification | £2,600 to £3,000 per m² |
| Good specification | £3,000 to £3,500 per m² |
| High specification | £3,500 to £4,000 per m² |
Do you need permission for a single-storey extension in Carshalton?
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.
In England a single-storey rear extension can often go ahead under permitted development: up to 3 m deep on an attached house or 4 m on a detached one, no higher than 4 m, with eaves no higher than 3 m within 2 m of a boundary. Deeper extensions, up to 6 m or 8 m, need prior approval from the council first.
What should I think about before starting?
- Building on or near a shared boundary usually means serving a party wall notice in England and Wales.
- Kitchens and doors have long lead times, so we order them early.
What happens after I enquire?
- Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
- We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
- Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
- Construction and completion. One site lead co-ordinates every trade through to the building control certificate.
Questions about a single-storey extension in Carshalton
Do I need planning permission for a single-storey extension?
Often not in England, if the extension stays within permitted development limits: 3 m deep on an attached house or 4 m on a detached house, and no higher than 4 m. Larger ones need prior approval or a planning application. Wales, Scotland and Northern Ireland have their own rules.
Will the brick match?
We source the closest available match for colour, size and texture and agree a sample panel with you before laying.
Do you work in Carshalton?
Yes. Carshalton is within our coverage for single-storey extensions, along with nearby Sutton and Mitcham.
Other towns nearby
- Single-storey extensions in Sutton
- Single-storey extensions in Mitcham
- Single-storey extensions in Morden
- Single-storey extensions in Croydon
Learn more about single-storey extensions, or see every project we cover in Carshalton.

