Two-storey rear extensions in Greenford

Before you start in Greenford, here's what applies.

Postcode districts: UB6
County / area: Greater London, England
Price region: London
Guide price: £67,000–£90,500 (£2,400–£3,240 per m²)
Approval route: It may be permitted development if it goes no more than 3 m beyond the original rear wall (counting any single-storey part) and stays 7 m from the rear boundary; otherwise it needs planning permission.
Nearest towns: Northolt (1.5 miles), Southall (1.5 miles), West Ealing (1.7 miles)
First visit: Free, no obligation

About a two-storey rear extension

A two-storey rear extension suits you if you need more room on both floors and have a reasonably deep garden. You get one team for the whole job: a measured survey, the design, a check on whether permitted development applies, planning drawings where they are needed, structural design, building regulations approval and the build itself, carried out by vetted teams working under S&K. Every project starts with a free site visit.

Around Greenford we also work in Northolt, Southall and West Ealing, and across the rest of Greater London. Postcode district in and near Greenford: UB6.

What it costs in Greenford

Most of the cost of a two-storey rear extension is set by its size and specification. For Greenford and the rest of London, our guide is £2,400–£3,240 per m² including VAT, so about £67,000–£90,500 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). Kitchens, bathroom fittings and flooring are priced separately so you can compare like with like.

Spec	Per m²	A 4 m × 3.5 m footprint on two floors (28 m² of new floor space)
Essential	£2,210–£2,980 per m²	£62,000–£83,500
Standard	£2,400–£3,240 per m²	£67,000–£90,500
Premium	£2,880–£3,890 per m²	£80,500–£109,000

Planning and building regulations in Greenford

In England, a two-storey rear extension can be permitted development if it goes no more than 3 m beyond the rear wall of the original house, stays at least 7 m from the rear boundary and matches the house's materials and roof pitch. It is not permitted development in conservation areas, National Landscapes, National Parks, World Heritage Sites or the Broads. Otherwise a householder application costs £548 (or £575 for applications made from 8 December 2026).

Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.

Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.

Design points for Greenford homes

Depth and neighbours' light

Councils check that a two-storey rear extension does not take too much light or outlook from neighbouring windows, and many use a 45-degree line drawn from the nearest habitable window. We test this at sketch stage, so the depth you are shown is one that can realistically be approved.

Roof form

A hipped or gabled roof that matches the pitch of the main house usually looks best, and matching the pitch is a permitted development condition in England. Keeping the ridge below the main ridge makes the extension read as secondary and avoids awkward junctions with existing gutters and windows.

How we'd run your project

Measure and listen
A visit to Greenford to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in England before drawing in detail.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
Build and hand over
We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.

Questions about two-storey rear extensions in Greenford

How much does a two-storey rear extension cost in Greenford?

Our guide for London, which covers Greenford, is £2,400–£3,240 per m² including VAT. A typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) comes to about £67,000–£90,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Which postcodes do you cover around Greenford?

We cover Greenford (UB6) and nearby places including Northolt, Southall and West Ealing, plus the rest of Greater London. The first site visit is free.

Do I need planning permission for a two-storey rear extension in Greenford?

Greenford is in England, so England planning rules apply. It may be permitted development if it goes no more than 3 m beyond the original rear wall (counting any single-storey part) and stays 7 m from the rear boundary; otherwise it needs planning permission. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.

Will a two-storey rear extension block my neighbour's light?

It can if it is too deep or too close to the boundary, which is why councils look closely at its effect on neighbouring windows and gardens. We test the design against light and outlook early, keep the first floor shorter or set in where needed, and use a hipped roof to reduce bulk on the boundary side.

Can I have a balcony on a two-storey rear extension?

In England, balconies, verandas and raised platforms are not permitted development, so a balcony on a two-storey rear extension needs planning permission. A Juliet balcony, a guard rail across full-height doors with no platform to stand on, is often a practical alternative, but it still needs checking against the rules and the council's approach to overlooking.

Nearby

The same service in neighbouring towns:

Other extensions in Greenford

All two-storey extension services in Greenford · Two-storey rear extensions across Greater London

Tell us about your house in Greenford and we'll call you back to arrange a free, no-obligation visit.