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House Extensions Merton

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

GS Renovation designs and builds extensions throughout Merton, working with the bay-fronted Victorian and Edwardian terraces and larger suburban homes near Wimbledon Common and Morden Hall Park. Across SW19, SW20, CR4 and SM4 we have over 30 years of experience turning tight rear yards and unused side returns into bright, well-built living space.

A rear extension under construction by GS Renovation, with cavity blockwork built up and the damp proof course laid
Blockwork to damp proof course level, with the membrane dressed over before the next lift goes on.

Side-return and rear extensions in Merton

The side return alongside the rear closet wing is the classic opportunity on a Merton terrace. Infilling that narrow strip and pushing the back wall out creates the open-plan kitchen-diner that suits family life near Wimbledon and Mitcham. We handle the groundworks and foundations, the steel beams that carry the original rear wall, the roof with its rooflights, and the full fit-out inside.

Wrap-around extensions combine the side return with a rear addition for a larger footprint, while double-storey options add a bedroom above. On the generous plots found around Morden and the leafier SW20 streets there is often room to extend more ambitiously, always built to sit correctly against the existing solid-wall structure.

Planning and party walls with Merton Council

Whether your extension is permitted development or needs a full planning application depends on the property. Many single-storey rear extensions fall under permitted development, but larger schemes, side extensions, corner plots and anything near a conservation area may require permission from Merton Council. We assess your specific house first and prepare the right application rather than assume.

Every extension also brings building regulations for the foundations, steel and drainage, inspected as the work proceeds. Where your new footings or walls sit against the shared party wall, the Party Wall Act applies too, so you serve the notices your neighbours are entitled to and keep the whole approvals process moving in one coordinated programme.

  • Trial holes to set foundation depth near drains and trees
  • Wrap-around extensions and infills
  • Building control inspections at foundation, damp course and steel stages
  • Single and double storey extensions
  • Full fit-out, finishing and making good
Service areaMerton · SW19, SW20, CR4 and SM4
Local authorityMerton Council
Part ofSouth West London (Outer London)
Typical homesVictorian villas, Edwardian terraces and substantial suburban homes
Also covered nearbyWandsworth, Lambeth, Croydon, Sutton and Kingston upon Thames

Trusted House Extensions in Merton

Merton families choose GS Renovation because we manage the extension end to end, from the first structural drawings and the Merton Council application through to the finished kitchen. One accountable team means tidy working in an occupied home, honest pricing and a build that respects the period fabric, backed by 30+ years across the borough.

  • Site left safe and secure at the end of every day
  • Free follow-up visit after completion if anything needs attention
  • Garden levels and access made good where the build meets outside
  • Scaffolding and site set-up planned for tight London plots
  • Materials priced at options, so you choose the finish
  • Waste cleared as we go, not left piled in the garden
30+ YearsFounder's experience
Fully Insured5 year guarantee
4.9 / 531 MyBuilder reviews
Building ControlCompliant
Free QuotesNo obligation
Reviews

Rated 4.9 / 5 by our clients

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

★★★★★
Really great job done in our bathroom to replace the shower head in the bathtub, and install a shower screen and caddy. We are very happy with the…
anja33030Enfield · via MyBuilder
★★★★★
George was very friendly and helpful from start to finish. He worked really hard to ensure our kitchen was installed to a high standard and was…
sophie35636Wanstead, London · via MyBuilder
★★★★★
We loved working with George and Ibrahim and would highly recommend them. They have done splendid job on our new kitchen refurb which including new…
kath833Wood Green, London · via MyBuilder
Read all 31 reviews

FAQ

Frequently Asked Questions about House Extensions Merton

Is the price of house extensions higher in Merton than elsewhere in South West London?

No. House extensions are priced from scope, so a Merton home is not quoted higher than the same house over in Wandsworth. Where costs do rise is in period stock and awkward access, both of which are checked at the SW19 property. GS Renovation shows those as separate lines so you can see the reason. The SW19 survey costs nothing and there is no obligation afterwards, in Merton or anywhere in Merton. 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 soon could you begin house extensions work at an SW19 address?

Faster than most people assume, provided the survey is done early. The lead time on house extensions at an SW19 property is usually approvals and materials rather than labour, so GS Renovation starts both as soon as the Merton scope is signed off. Seasonal demand across Merton does move it. Email info@gsrenovationltd.co.uk for the current position on Victorian and Edwardian terraced properties. The SW19 survey is free and there is no obligation afterwards in Merton.

Can you give references for house extensions carried out near Merton?

Happily. Previous Merton clients are usually willing to talk about how a house extensions project actually ran, including what went wrong and how GS Renovation dealt with it. We will point you at recent work near SW19 and in Wandsworth. The 31 MyBuilder reviews behind our 4.9 rating are public and cover the same ground. Ring 07472 424 226 to arrange a Merton introduction. Nothing about a Merton reference is curated by us at SW19.

Will an extension in Merton need a CIL payment?

It can. The Community Infrastructure Levy applies above 100 square metres of new floorspace, though a residential extension to your own home usually qualifies for relief if it is claimed before work starts. Missing that claim is expensive, so we flag it early on Merton projects.

How does Merton's Victorian and Edwardian terraced housing affect a house extensions project?

It lengthens the preparation and the finishing. A house extensions job at an SW19 address of that age begins with investigation and ends with reinstating plaster, floors and joinery to match what is already in the Merton house. GS Renovation itemises both. Merton Council inspects the structural stages in between, exactly as it would in Merton generally. Email info@gsrenovationltd.co.uk and we will explain what house extensions adds in reinstatement at an SW19 address of that age.

Will my Merton rear extension need planning permission or is it permitted development?

It depends on the property. Many single-storey rear extensions on Merton terraces are permitted development within size limits, but side-return, double-storey and larger schemes, or homes in a conservation area, often need a full application to Merton Council. We check your exact address and permitted development rights first, then handle whichever route applies.

Do you work beyond Merton on house extensions projects?

Regularly, though we do not pretend to cover everywhere. The house extensions patch runs across Merton and into neighbouring parts of South West London, which is wide enough to include most enquiries we receive from around SW19. GS Renovation would rather decline a job than take one it cannot service properly. Ring 07472 424 226 and ask about your Merton address. The answer comes the same day. The SW19 survey costs nothing and carries no obligation.

Every Service, One Team

More GS Renovation Services in Merton

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

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Free, no-obligation quote for house extensions in Merton. Rated 4.9 from 31 reviews on MyBuilder, fully insured, and building control handled for you.

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