Mortlake, Greater London
Wraparound extension in Mortlake
An L-shaped extension that fills the side return and runs across the back. We design, get the approvals for and build wraparound extensions in Mortlake and the surrounding area, with one contract from the first survey to building control sign-off.
We cover Mortlake (SW13, SW14 and TW9) as part of our Greater London work. Wraparound projects around Mortlake often involve two neighbours, so we start the party wall conversations early.
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 wraparound extension cost in Mortlake?
For Mortlake we work from the London rate: £2,860–£4,680 per square metre of new floor, including VAT, standard specification. 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 |
|---|---|
| L-shaped, about 22 m² of new floor | £63,000–£103,000 |
| L-shaped, about 30 m² of new floor | £86,000–£140,500 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a wraparound extension in Mortlake?
Here is how the rules in England apply to a wraparound extension in Mortlake.
Side return infills and the side leg of a wraparound are treated as side extensions in England: single-storey, no more than 4 metres high and no wider than half the original house. They are not permitted development in conservation areas, National Parks or National Landscapes, and a joined wraparound often needs a planning application because the side and rear rules apply together.
The Party Wall etc. Act 1996 applies in England: you serve notice two months before work to a shared wall, and one month before digging foundations within 3 metres (or 6 metres for deeper foundations) of a neighbour's building. Neighbours can agree in writing; if they dissent, surveyors agree an award.
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 Mortlake like to extend?
Period terraces in Mortlake sit alongside flats, and the difference matters: houses usually keep permitted development rights, while flats and maisonettes need planning permission for any rear extension.
How a wraparound extension in Mortlake comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
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.
Wraparound extensions near Mortlake
Neighbouring places we cover include East Sheen (0.5 miles) and Barnes (0.9 miles).
- Wraparound extension in East Sheen
- Wraparound extension in Barnes
- Wraparound extension in Kew
- Wraparound extension in Roehampton
- Wraparound extension in Chiswick
Other work in Mortlake:
FAQ
Wraparound extension questions in Mortlake
Do I need planning permission for a rear extension in Mortlake?
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 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.
Can the corner be all glass?
Yes, with a steel or aluminium post or a structural glass corner. It needs careful thermal detailing to meet Building Regulations.
How long does a rear extension take to build in Mortlake?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.