Cost Guide 2025

House Extension Cost in Richmond

A house extension can transform your home, adding valuable living space. Costs cover foundations, structural work, roofing, glazing, internal fit-out, and connection to existing services. In Richmond (TW9, TW10), costs reflect the area's Inner London market position, with a 5% premium over London averages.

£2,625 – £5,775/sqm Estimated range for
Richmond (TW9, TW10)

House Extension Costs in Richmond

Richmond is one of London's most attractive boroughs, known for its riverside setting, stunning park, and charming Georgian town centre. Properties range from riverside mansions to elegant terraced houses.

Specification Price per sqm Typical 25sqm Project Includes
Standard
Quality materials, clean design
£2,625 – £3,360 £65,625 – £84,000 All structural work, standard fixtures, full fit-out and decoration
Premium
Designer brands, bespoke elements
£3,360 – £4,200 £84,000 – £105,000 Premium materials, designer fixtures, underfloor heating, smart controls
Luxury
Finest materials, fully bespoke
£4,200 – £5,775 £105,000 – £144,375 Bespoke joinery, natural stone, top-tier appliances, architectural detailing

Prices include VAT and are based on Richmond (TW9, TW10) market rates. Prices reflect Inner London market conditions and local construction costs. Actual costs depend on site-specific factors. All prices are guide estimates for 2025.

A 25sqm House Extension in Richmond

Here's what a typical 25sqm house extension project would cost in Richmond at each specification level.

Standard
£65,625 – £84,000
25sqm at £2,625–£3,360/sqm
Quality materials, clean finish
Premium
£84,000 – £105,000
25sqm at £3,360–£4,200/sqm
Designer brands, bespoke elements
Luxury
£105,000 – £144,375
25sqm at £4,200–£5,775/sqm
Finest materials, fully bespoke

What Affects House Extension Costs in Richmond

Richmond has extensive conservation areas covering the town centre, riverside, and Richmond Hill. The famous view from Richmond Hill is legally protected by Act of Parliament.

Key streets and roads in Richmond include Richmond Hill, The Terrace, Friars Stile Road, Queen's Road, Ormond Road. Properties in these locations often have specific architectural characteristics that influence renovation costs, including protected viewpoint considerations, riverside flood risk, Georgian property specialist requirements, premium location commanding premium specifications.

  • Foundation requirements and ground conditions
  • Proximity to boundaries and neighbours
  • Roof design — flat, pitched or glazed
  • Level of glazing and bi-fold doors
  • Connection to existing structure

Richmond Area Profile

Postcodes: TW9, TW10

Market tier: Inner London

Price adjustment: +5% vs base London rates

Richmond is one of London's most attractive boroughs, known for its riverside setting, stunning park, and charming Georgian town centre. Properties range from riverside mansions to elegant terraced houses.

Richmond: ×1.05 multiplier

Get a Precise Quote for Your Richmond Project

Every house extension is unique. Let our RIBA chartered architects provide a detailed, no-obligation estimate tailored to your property and specification.

Use our interactive calculator for a personalised estimate

House Extension in Richmond — FAQs

How much does a house extension cost in Richmond?
House extensions in Richmond cost between £2,200-£4,000/sqm depending on specification. A standard 25sqm rear extension starts around £55,000, while a premium specification with high-end finishes can exceed £80,000-£100,000.
Do I need planning permission for a house extension in Richmond?
Many single-storey rear extensions of up to 6m (detached) or 3m (terraced/semi) fall under permitted development. However, properties in conservation areas in Richmond often have restricted PD rights. We provide full planning guidance for every project.
How long does a house extension take in Richmond?
A typical ground-floor rear extension takes 10-16 weeks on site. Side-return extensions are often quicker at 8-12 weeks. Double-storey extensions may take 14-20 weeks. Access constraints in Richmond can affect programme.
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