Having the Beams team on hand to manage the project and provide extra reassurance on build decisions was incredibly helpful and made the whole experience stress free.
Kerry
London
They have been extremely efficient and reassuring. It was a complex project but they took it all in their stride. They recommended very good contractors who were all punctual, polite and capable.
Andrew
London
All about trust. I felt comfortable with my money, my project, and my home knowing that the outcome would be to my satisfaction or would be made good.
Chris
London
Lambeth extension builders who design and build
An extension in Lambeth usually means working within a terrace, a conversion, or a tight urban plot around Clapham, Brixton, Kennington or Vauxhall. Beams handles design and build under one roof, so the same team that draws the plans is accountable for delivering them, on a fixed price agreed before work starts.
Our in-house designers plan the extension around your home and how you live, and a vetted builder delivers it, with milestone payments and a 12-month workmanship warranty.
Types of house extension we build
Side-return extension: Fills the alley beside a terrace to widen the kitchen.
Rear extension: Extends into the garden for a bigger kitchen or living space.
Wraparound extension: Combines side-return and rear for maximum ground-floor space.
Double-storey extension: Adds space on two floors at once.
What a house extension costs in Lambeth
Cost depends on the footprint, the structural work involved and the specification. Based on Beams estimates for London house extension projects, here is a general guide:
Project type | Typical estimate |
|---|---|
Lower end | £45,000 |
Most projects | £75,000 |
Larger or higher spec | £120,000 |
Top 10% of projects | £180,000 |
These are estimate ranges rather than fixed quotes. A single-storey side-return sits at the lower end, while a wraparound or double-storey extension pushes it higher. Your fixed price is confirmed once the design is agreed.
Planning permission for extensions in Lambeth
Many single-storey rear extensions fall under permitted development, though this varies with your home and street. Lambeth has more than 60 conservation areas, including Kennington, Albert Square, Clapham Old Town and Vauxhall, and homes within them, along with flats, maisonettes and listed buildings, generally need full planning permission for any extension. We check the position for your address and, where needed, manage the application with Lambeth Council.
Our design and build process
1. Free first call: Tell us about your home, budget and what you need the space for.
2. Design and planning: Our designers draw the extension and handle any planning application.
3. Fixed-price build: A vetted builder delivers it under contract, with milestone payments.
Why an extension is worth it
Moving house comes with stamp duty, agent fees and the upheaval of a new area. Extending gives you the space you need while staying put, and a well-designed extension adds day-to-day comfort as well as resale value.
Extending a home in Lambeth
Lambeth's terraced streets around Clapham, Brixton and Stockwell are classic side-return territory, while Georgian terraces near Kennington and Vauxhall often carry conservation area rules that call for full planning permission rather than permitted development. Streatham, the borough's southern neighbourhood, is covered by its own dedicated Beams pages.
With the average Lambeth home selling for around £537,000 in the year to July 2026 (ONS/HM Land Registry, provisional), a well-planned extension is a strong way to add both space and value. Our designers and vetted builders also cover the nearby boroughs of Southwark and Wandsworth.
Other services in Lambeth
We also help Lambeth homeowners with:
Bathroom renovation in Lambeth
Basement conversion in Lambeth
House extensions in nearby areas:
Ready to extend your Lambeth home?
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