First-floor extensions in Catford
We plan and build first-floor extensions for homeowners in Catford and nearby. Every project starts with a free visit and a design stage priced in writing before any work begins.
What we'd confirm first for a project in Catford.
- Postcode districts
- SE6
- 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
- Lewisham (0 miles), Ladywell (0.7 miles), Crofton Park (0.8 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 postcode district SE6 in and around Catford, along with neighbouring Lewisham, Ladywell and Crofton Park.
What it costs in Catford
Guide prices for first-floor extensions in London are around £2,160–£3,120 per m² of new floor space, including VAT. For a typical project with 4 m × 3.5 m of new first-floor space (14 m²), that's roughly £30,000–£43,500. Kitchens, bathroom fittings and flooring are priced separately so you can compare like with like.
| 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 Catford
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 Catford homes
Can the existing structure take it?
Many single-storey extensions were built with foundations, walls and lintels sized for one storey. We find out what is there with trial holes and, where available, the original building control drawings. The engineer then decides whether to reuse, strengthen or rebuild parts of the structure.
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.
How we'd run your project
Visit and first ideas
One of our team visits your house in Catford, checks the walls, roof and drains, and sketches out options with you.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in England before drawing in detail.
Detail and price
Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.
Questions about first-floor extensions in Catford
How much does a first-floor extension cost in Catford?
Our guide for London, which covers Catford, 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.
How long does a first-floor extension take?
Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.
Which postcodes do you cover around Catford?
We cover Catford (SE6) and nearby places including Lewisham, Ladywell and Crofton Park, plus the rest of Greater London. The first site visit is free.
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.
What happens to the room below while the first floor is built?
The old roof is removed, so the room below is exposed for a short period. We fit temporary weather protection, plan the work so the roof comes off only when the new structure is ready, and agree with you which rooms will be out of use and for roughly how long.
Nearby
Nearby towns we cover for first-floor extensions:
Other extensions in Catford
- 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 Catford · First-floor extensions across Greater London
Want a figure first? Try our guide price tool, then book a free visit to firm it up.