Double-storey extensions across Horsforth
Thinking about a double-storey extension for your Horsforth home? Start with a free site visit: we measure up, check what the council will allow and give you honest guide figures on the day.
- Guide price in HorsforthFrom £35,500 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsLS16, LS18
What is included
- Breaking through at both levels, stairs and landing changes where needed
- Measured survey, design and planning drawings
- Ground and first floor structure, roof tied into the existing roof
- Foundations sized for two floors
- Householder planning application where needed
- Building regulations drawings and structural design
The roof is what makes a two-storey extension look right or wrong. We match the pitch and materials of the main house wherever possible and plan the upstairs layout around the existing landing so the new rooms feel original rather than bolted on.
Working in Horsforth
Our survey diary covers Horsforth, including LS16, LS18. Nearby, we also take on projects in Yeadon (3 miles), Pudsey (3 miles), Guiseley (4 miles), Leeds (5 miles).
For homes towards North Yorkshire, Harrogate is around 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.
Guide prices for 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: £1,460 to £2,820 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m, two floors 24 m² | £35,500 – £43,000 | £40,500 – £53,500 | £51,500 – £68,000 |
| 4 m × 4 m, two floors 32 m² | £46,500 – £56,000 | £54,000 – £71,000 | £69,000 – £90,500 |
| 4 m × 6 m, two floors 48 m² | £69,500 – £83,500 | £81,000 – £106,500 | £103,500 – £135,500 |
Try the guide-price tool to see a range for your own size and finish.
Will the council need to approve it?
In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
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).
Our process, step by step
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
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Questions people ask about double-storey extensions
How long does a double-storey extension take to build in Horsforth?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 8–16 weeks design and approvals.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Horsforth, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
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.
Is a two-storey extension cheaper per square metre?
Usually. Our guide range is about £1,460 to £2,820 per m² of new floor area including VAT, compared with £1,640 to £3,200 per m² for single-storey work, because the foundations and roof are shared across two floors.
Does a double-storey extension need planning permission?
Often, yes. In England a two-storey rear extension can be permitted development only if it projects no more than 3 m and sits at least 7 m from the rear boundary, with matching roof pitch and obscure side windows. Side extensions over one storey always need planning permission. We confirm the route at the survey.
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.