Flat roof extensions across Horsforth
From the first sketch to final sign-off, we plan and build flat roof extensions in Horsforth and the surrounding West Yorkshire area.
- Guide price in HorsforthFrom £19,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time10–16 weeks on site
- Postcode districtsLS16, LS18

When a flat roof extension makes sense
- Modern and 1930s onwards houses
- Homeowners who want maximum light from above
- Extensions under first-floor windows where a pitch will not fit
Height is often what decides a flat roof. Under first-floor windows, a pitched roof may not fit at all; a flat roof keeps the extension low while still giving a good ceiling height inside.
Do I need planning permission in Horsforth?
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
What should I budget for a flat roof extension in Horsforth?
Prices below are for Horsforth, using the Yorkshire and the Humber factor of ×0.94. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Horsforth: £1,640 to £3,150 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £19,500 – £23,500 | £23,000 – £29,500 | £29,000 – £38,000 |
| 4 m × 5 m 20 m² | £32,500 – £39,000 | £38,500 – £49,000 | £48,500 – £63,000 |
| 5 m × 6 m 30 m² | £49,000 – £58,000 | £57,500 – £73,500 | £73,000 – £94,500 |
For a figure based on your own dimensions, use our guide-price tool.
Extensions in and around Horsforth
Site visits are available across Horsforth (LS16, LS18). Neighbouring towns we cover include Yeadon (3 miles), Pudsey (3 miles), Guiseley (4 miles), Leeds (5 miles).
Just over the North Yorkshire border, Harrogate is about 11 miles away. Yorkshire and the Humber combines stone-built terraces in the Pennine towns with brick semis and newer estates elsewhere, so materials and roof details need matching with care.
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
We visit your Horsforth home, measure up, talk through what you want and check the planning position.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Your questions about a flat roof extension in Horsforth
Will my neighbours in Horsforth be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Do you cover all of Horsforth?
Yes. We cover Horsforth and the surrounding parts of West Yorkshire. Site visits are free and there is no obligation.
Who do I contract with for a flat roof extension in Horsforth?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Are flat roof extensions cheaper?
Usually slightly, because there is less roof structure and no tiles. Our guide range is about £1,640 to £3,150 per m² including VAT.
Can I walk on a flat roof extension?
Only for maintenance unless it is designed as a terrace. A roof terrace or balcony needs planning permission and a different structure.
Book a free site visit in Horsforth
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.