Carshalton, Greater London
Glazed rear extension in Carshalton
For homes in Carshalton, a glazed rear extension is often the simplest way to gain space without moving. Full-height glass, slim frames and big rooflights for the most open rear room. We take it from survey to completion certificate.
Carshalton sits in Greater London, with postcode districts including SM1, SM5 and SM6. If your garden in Carshalton faces south, expect us to talk about overhangs and solar-control glass before frame colours.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a glazed rear extension cost in Carshalton?
Guide prices for a glazed rear extension in Carshalton start from our London rate of £3,640–£6,240 per square metre, including VAT. London prices sit at the top of our range because of labour rates, access through the house, parking suspensions and skip licences.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £43,500–£75,000 |
| 4 m wide × 6 m deep (24 m²) | £87,500–£150,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a glazed rear extension in Carshalton?
The planning route for a glazed rear extension in Carshalton is set by England's householder rules and your council.
Under England's householder permitted development rules you can usually add 3 metres at the back of an attached house, or 4 metres on a detached house, without a planning application, as long as the extension stays under 4 metres high and its eaves stay under 3 metres where it is within 2 metres of a boundary.
New fabric must meet Approved Document L (2021 edition incorporating 2023 amendments): walls 0.18, roof 0.15 and floor 0.18 W/m²K, windows 1.4 W/m²K or Band B. Under the simple route, new windows, doors and rooflights should not exceed 25% of the extension floor area plus any openings removed; more glass is possible with a whole-house calculation.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Carshalton like to extend?
Carshalton is mostly 1930s semis, short terraces and post-war houses, so full-width single-storey and two-storey rear extensions are realistic on many plots. Some later estates had permitted development rights removed by condition, so we check the planning history first.
How a glazed rear extension in Carshalton comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Glazed rear extensions near Carshalton
We also build glazed and glass-box rear extensions in nearby Wallington (0.7 miles) and St Helier (1.2 miles).
- Glazed rear extension in Wallington
- Glazed rear extension in St Helier
- Glazed rear extension in Sutton
- Glazed rear extension in Belmont
- Glazed rear extension in Cheam
Other work in Carshalton:
FAQ
Glazed rear extension questions in Carshalton
How long does a rear extension take to build in Carshalton?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
What postcode areas do you cover around Carshalton?
Including SM1, SM5 and SM6, and the surrounding Greater London area.
Can I have a level threshold?
Yes, with a drainage channel outside the doors and the slab set to the patio level.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
Do I need planning permission for a rear extension in Carshalton?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.
Do you handle building control in Carshalton?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.