House Extensions South London 2026: Complete Guide to Costs, Planning and Areas

South London is one of the fastest-growing residential markets for home extensions in the capital — with strong property values across Wandsworth, Lambeth, Southwark, Merton, Richmond and surrounding boroughs. The area's mix of Victorian and Edwardian terraces, together with excellent transport connections and rising demand from families, makes house extensions here one of the smartest home improvement investments available. This guide sets out extension costs, planning permission rules and best extension types across all of South London for 2026. LCCL Construction delivers house extensions across South London and all of Greater London as part of our complete design and build service.

LCCL Construction — specialist house extension builders across South London

Best House Extension Types for South London Properties

South London's Victorian terraces suit wraparound extensions combining rear and side return for maximum ground floor space. Semi-detached properties in Balham, Streatham and Wimbledon are ideal for double storey extensions that add bedrooms upstairs plus kitchen/dining space downstairs.

House Extension Costs in South London 2026

Rear extension: £35,000 to £75,000.

Side return: £35,000 to £75,000.

Wraparound: £60,000 to £128,000.

Double storey: £75,000 to £165,000.

All include full design and build. See our full home extension cost guide.

South London Areas We Cover

LCCL Construction covers all South London postcodes including Clapham SW4, Wandsworth SW18, Battersea SW11, Balham SW12, Tooting SW17, Streatham SW16, Brixton SW2, Wimbledon SW19, Putney SW15, Fulham SW6, Chelsea SW3, Southfields SW18, Earlsfield SW18, Roehampton SW15, Richmond TW9 TW10, Barnes SW13, East Sheen SW14, Twickenham TW1 TW2, Kingston KT1 KT2, Dulwich SE21 SE22, East Dulwich SE22, Peckham SE15, Camberwell SE5, Herne Hill SE24, Forest Hill SE23 and surrounding areas.

Planning Permission for South London House Extensions

Planning requirements vary significantly across South London boroughs. The London Borough of Wandsworth covers most of Wandsworth, Balham, Battersea, Tooting and Putney with extensive conservation areas. Lambeth covers Clapham, Brixton and Streatham. Merton covers Wimbledon. Southwark covers Dulwich and Peckham. Article 4 directions apply in many streets. LCCL Construction handles all planning applications. See our full house extension planning permission guide.

How Much Value Does a House Extension Add in South London?

A wraparound extension costing £85,000 typically adds £150,000 to £280,000 to the value of a South London Victorian terrace.

A double storey extension costing £110,000 typically adds £190,000 to £330,000.

Extensions in premium South London locations (Chelsea, Fulham, Wimbledon, Richmond) can deliver even higher returns.

Frequently Asked Questions About House Extensions in South London

How much does a house extension cost in South London?

From £35,000 for a small rear extension to £165,000+ for a large double storey. Premium locations like Wimbledon and Richmond cost 10-20 per cent more.

Do I need planning permission for an extension in South London?

Most extensions in South London require planning permission due to widespread conservation areas and Article 4 directions across Wandsworth, Lambeth and Merton.

To book a free consultation call LCCL Construction on 020 8037 7332 or get an instant quote online.