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House Extensions Lewisham

Single and double storey extensions in Lewisham. Trusted, professional, 30+ years' hands-on experience.

GS Renovation designs and builds extensions across Lewisham, adding space to the bay-fronted Victorian and Edwardian terraces of Catford, Forest Hill and New Cross. With 30+ years working in SE6, SE23 and SE26, we handle everything from foundations and steel to the final fit-out, whether your project runs as permitted development or needs a full planning application.

House Extensions in Lewisham, London by GS Renovation
House Extensions by GS Renovation in Lewisham.

Side-return and rear extensions in Lewisham

The side return, that narrow strip beside the rear closet wing, is the most valuable space on a Lewisham terrace. Filling it in widens a cramped galley kitchen into a proper kitchen-diner running the full width of the house. We dig new foundations to suit the ground and any nearby trees, tie the new brickwork into the existing wall, and carry the original structure on a steel beam where the outside wall comes out.

A rear extension pushes the back of the house into the garden, often combined with the side return as a wrap-around. On these terraces we usually add generous rooflights or a lantern to bring daylight deep into the plan, since the middle of a terrace can be dark. Bi-fold or sliding doors open the new room to the garden. We manage the roof works, insulation and weathering so the extension is warm, dry and built to current standards.

Planning and permitted development across Lewisham

Many single storey rear and side-return extensions in Lewisham fall under permitted development, meaning no full planning application, though we normally secure a lawful development certificate from Lewisham Council for peace of mind and future sale. Size limits, height and how close you build to the boundary all matter. Double storey extensions, anything facing the street, and work in a conservation area or on a listed building usually need planning permission.

Parts of Blackheath, Telegraph Hill and the streets around the Horniman Museum sit in conservation areas, where the council looks closely at materials and appearance. Whichever route applies, the build itself must meet building regulations, covering foundations, structure, insulation, fire safety and drainage, all inspected by building control. We advise early on the likely route for your address, prepare the drawings, and handle party wall notices where the extension affects a shared boundary.

  • Full fit-out, finishing and making good
  • Architectural drawings and structural coordination
  • Single and double storey extensions
  • Side-return and rear extensions
  • Wrap-around extensions and infills
Service areaLewisham · SE4, SE6, SE8 and SE13
Local authorityLewisham Council
Part ofSouth East London (Inner London)
Typical homesBay-fronted Victorian and Edwardian terraces with rear closet wings and side returns
Also covered nearbyGreenwich, Southwark and Bromley

Why Choose GS Renovation in Lewisham

Homeowners across SE4, SE13 and SE23 choose GS Renovation because we take an extension from first sketch to finished room as one team. We advise honestly on planning versus permitted development, engineer the structure properly, and coordinate the party wall side. With 30+ years on Lewisham terraces, you deal with one accountable contractor throughout.

  • Free, no-obligation quotations
  • Over 30 years of hands-on experience
  • Dedicated project management
  • Fully insured and guaranteed work
  • Building control and planning support
  • Clean, tidy and reliable tradespeople
30+ YearsExperience
Fully Insured& Guaranteed
500+ ProjectsCompleted
Building ControlCompliant
Free QuotesNo obligation
Reviews

Rated 4.9 / 5 by our clients

★★★★★ 4.9 average from 31 verified reviews on MyBuilder

★★★★★
George was brilliant. Lovely bloke, very reasonably priced and a perfectionist to boot. He completed our small kitchen renovation with care and great attention to detail. I've already recommended him to others.
OscarCrofton Park, London · via MyBuilder
★★★★★
Splendid job on our new kitchen refurb, including new flooring, moving the services, installing RSJ and preparing space for new back doors… George was always friendly, communicative and has an excellent attention to detail, ensuring everything is finished to a high standard.
KathWood Green, London · via MyBuilder
★★★★★
Giorgio is an excellent and intelligent workman, and with very reasonable prices!… He paid a lot of attention to detail that is not common at all, and the final result was immaculate. Highly recommended!
Adil KhanWoolwich, London · via MyBuilder
Read all 31 reviews on MyBuilder

FAQ

Frequently Asked Questions about House Extensions Lewisham

How much does house extensions cost in Lewisham?

Every Lewisham project is priced on its own merits, as the cost of house extensions varies with the size, specification and condition of the home. We give a clear, itemised quote up front with no obligation. Call 07472 424 226 for an estimate tailored to your property. As a rough guide, house extensions in London typically starts from roughly £40,000 for a single-storey rear extension and rises with size and specification (indicative London ranges, MyBuilder and Checkatrade, 2026). Your figure depends on the size, specification and condition of the property, which is why we survey before quoting.

How long does house extensions take in Lewisham?

Timescales for house extensions in Lewisham vary with the size and complexity of the job. After our survey we give you a realistic schedule and keep you updated at every stage of the project.

Why choose GS Renovation for house extensions in Lewisham?

With more than three decades of hands-on trade experience behind us, GS Renovation is a trusted choice for house extensions in Lewisham. You get one accountable team, transparent pricing, fully insured tradespeople and genuine aftercare on every project.

Do I need planning permission for an extension in Lewisham?

Many single-storey rear extensions in Lewisham fall under permitted development, but side returns, double-storey extensions and work in conservation areas usually need full planning permission. We assess your property and manage both the planning application and building control.

Do you work on Victorian and Edwardian terraced homes in Lewisham?

Yes. A large share of Lewisham's homes are Victorian and Edwardian terraced properties, and we renovate them regularly. We plan each house extensions around their particular characteristics, such as solid brick walls, rear closet wings, side returns and original period features, so the result suits the building and meets building control.

Will my Lewisham side-return extension need planning permission?

Often it will not. A single storey side-return or rear extension on a Lewisham terrace frequently falls within permitted development, so no full planning application is needed, and we obtain a lawful development certificate to confirm it. However, if your home is in a conservation area near Blackheath or the Horniman Museum, is listed, or exceeds the size limits, planning permission from Lewisham Council is required. We check your address first.

Do you cover all of Lewisham?

Absolutely. Our team works right across Lewisham and the SE4 area and neighbouring parts of South East London. Get in touch on 07472 424 226 to check coverage for your address.

Every Service, One Team

More GS Renovation Services in Lewisham

The same trusted team, 30+ years' hands-on experience and free, no-obligation quotes apply to every GS Renovation service in Lewisham. Explore what else we do locally:

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Ready to Start Your Lewisham Project?

Contact GS Renovation today for a free, no-obligation quote for house extensions in Lewisham.

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Call 07472 424 226