First-floor extensions in Fulham
For a first-floor extension in Fulham, the first questions are always the same: how big, which approvals, and what it will cost. This page answers all three for Greater London.
Fulham: the key facts for this kind of project.
- Postcode districts
- SW6
- County / area
- Greater London, England
- Price region
- London
- Guide price
- £30,000–£43,500 (£2,160–£3,120 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
- Earls Court (0.8 miles), Chelsea (1.4 miles), Putney (1.6 miles)
- First visit
- Free, no obligation
About a first-floor extension
A first-floor extension is a new upstairs room built on top of an existing single-storey part of your house, such as a rear kitchen extension, a utility or a side annexe. It adds a bedroom, bathroom or study without enlarging the footprint. Whether it works depends mainly on whether the walls and foundations below can carry the extra load.
We cover Fulham (SW6) and the places around it, including Earls Court (0.8 miles), Chelsea (1.4 miles) and Putney.
What it costs in Fulham
Our guide for London is £2,160–£3,120 per m² including VAT. On a project with 4 m × 3.5 m of new first-floor space (14 m²), that puts a first-floor extension in Fulham at roughly £30,000–£43,500. Professional fees for drawings and the structural engineer are listed separately on our prices page.
| Spec | Per m² | 4 m × 3.5 m of new first-floor space (14 m²) |
|---|---|---|
| Essential | £1,990–£2,870 per m² | £28,000–£40,000 |
| Standard | £2,160–£3,120 per m² | £30,000–£43,500 |
| Premium | £2,590–£3,740 per m² | £36,500–£52,500 |
Planning and building regulations in Fulham
In England, adding a first floor turns a single-storey extension into one of more than one storey. To be permitted development, the extension as a whole must go no more than 3 m beyond the rear wall of the original house and stay at least 7 m from the rear boundary, with matching materials and roof pitch. Over a side extension it always needs planning permission, costing £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 Fulham homes
Tying into the house
The new floor and walls must line up with the existing first floor, often through a new opening in the rear wall above the old one. Floor levels, the position of upstairs windows and the existing roof all affect where the opening can go, so we survey both floors carefully.
Matching the roofline
A first-floor extension often changes how the back or side of the house looks more than the original single storey did. Matching the main roof pitch and materials, and keeping the ridge below the main ridge, usually gives the best result and is expected for permitted development in England.
How we'd run your project
Free site visit
We visit your home in Fulham, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
Build and hand over
We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.
Questions about first-floor extensions in Fulham
How much does a first-floor extension cost in Fulham?
Our guide for London, which covers Fulham, is £2,160–£3,120 per m² including VAT. A typical project with 4 m × 3.5 m of new first-floor space (14 m²) comes to about £30,000–£43,500. 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 Fulham?
We cover Fulham (SW6) and nearby places including Earls Court, Chelsea and Putney, plus the rest of Greater London. The first site visit is free.
Do I need planning permission for a first-floor extension in Fulham?
Fulham 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 the first-floor extension match my house?
It should, and in England matching materials and roof pitch is a condition of permitted development. We match brick, tile, mortar colour and window style where we can, and tell you at the design stage if an exact brick match is not available, so you can choose between the closest match and render or cladding.
Can I build on top of my existing single-storey extension?
Often yes, but only after the structure has been checked. Foundations, walls and lintels built for one storey may not carry two. We dig trial holes, look for the original building control approval and ask the structural engineer to confirm what can stay, what needs strengthening and what must be rebuilt.
Nearby
Other towns near Fulham:
Other extensions in Fulham
- Rear
- Side
- Wraparound
- Part two-storey
- Over a garage
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Fulham · First-floor extensions across Greater London
Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.