Home Extensions London 2026: Complete Guide to Costs, Types and Planning

A home extension is one of the most effective ways to add space and value to your London property. Whether you are planning a rear extension to create an open plan kitchen diner, a side return extension to widen the ground floor, a wraparound extension for maximum space or a double storey extension for both floors — LCCL Construction delivers all types of home extension across London and Hertfordshire as part of our complete design and build service.

LCCL Construction — specialist home extension builders across London and Hertfordshire

How Much Do Home Extensions Cost in London in 2026?

Home extension costs in London range from £42,000 inc. VAT (£35,000 + VAT) for a small single storey rear extension to £160,000 for a large double storey extension. The most popular home extension — a single storey rear extension creating a new kitchen diner — costs £42,000 – £90,000 inc. VAT (£35,000 – £75,000 + VAT). A wraparound extension combining rear and side return costs £42,000 – £93,600 inc. VAT (£35,000 – £78,000 + VAT). See our full house extension cost guide for a full breakdown by extension type.

Types of Home Extension in London

Rear home extension: The most popular type — extends the ground floor at the back of the property to create a new kitchen, dining room or open plan living space. From £42,000 inc. VAT (£35,000 + VAT).

Side return extension: Fills the narrow side alley alongside the rear of a terraced house to create a wider kitchen. From £42,000 inc. VAT (£35,000 + VAT).

Wraparound extension: Combines rear and side return for maximum ground floor space. From £72,000 inc. VAT (£60,000 + VAT).

Double storey extension: Adds space on both ground and first floors. From £85,000.

Do I Need Planning Permission for a Home Extension in London?

Most single storey rear home extensions in London can be built under permitted development without planning permission. Under the Larger Home Extension Scheme you can extend up to 6 metres for a terraced or semi-detached house and 8 metres for a detached house without planning permission. Properties in conservation areas always require planning permission. See our full guide to house extension planning permission in London.

How Much Value Does a Home Extension Add in London?

A well-designed home extension typically adds 10 to 20 per cent to the value of a London property. A wraparound extension costing £60,000 to £128,000 typically adds £110,000 to £180,000 in value — a return of 140 to 210 per cent. See our full guide on how much value an extension adds in London.

Why Choose LCCL Construction for Your Home Extension in London?

LCCL Construction is one of London's most trusted home extension companies. Over 20 years experience. 200+ reviews at 4.7/5. LABC Award Winners 2024 — Best Residential Extension London. LABC Registered Partners. NFB members. Complete design and build service — one company from initial design through planning permission, building regulations and construction to handover.

Can it be done under permitted development?

A single-storey rear extension of 3 m on a terrace or semi (4 m on a detached house), a side-return infill and a side extension up to half the original width are permitted development on a house outside a conservation area or Article 4 street — no planning application, just a Lawful Development Certificate, which we apply for on every one. Fixed-price permitted development extensions start from £42,000 inc. VAT (£35,000 + VAT) at economy specification, design and build inclusive, and the 6 m / 8 m larger home extension goes through a 42-day prior approval notification rather than a full application. See our permitted development projects page for every product with its from-price and the checks we run before we confirm a project qualifies. Not sure whether your project needs a planning application? Check if you need planning permission

Frequently Asked Questions About Home Extensions in London

How much does a home extension cost in London?

Between £35,000 and £160,000 depending on type and size. A typical rear extension costs £42,000 – £90,000 inc. VAT (£35,000 – £75,000 + VAT). A wraparound costs £72,000 – £153,600 inc. VAT (£60,000 – £128,000 + VAT).

Do I need planning permission for a home extension?

Most single storey rear extensions can be built under permitted development without planning permission. Conservation areas always require permission.

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