Swanley timber frame extensions, designed and built
Thinking about a timber frame extension for your Swanley 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 SwanleyFrom £23,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time8–14 weeks on site
- Postcode districtsBR8

Will the council need to approve it?
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 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.
Applications are decided by the local planning authority (your district, borough or unitary council).
Who a timber frame extension suits
- Sites where weight or speed matters
- Contemporary designs with timber or board cladding
- Homeowners who want strong energy performance
Moisture is the enemy of any timber building. We design ventilated cladding cavities, breather membranes and a proper damp-proof course height, and keep the frame dry during construction.
How much does a timber frame extension cost in Swanley?
Labour and material costs vary across the UK, so for Swanley we use our South East England factor (×1.12). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Swanley: £1,960 to £3,810 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £23,500 – £28,500 | £27,500 – £36,000 | £34,500 – £46,000 |
| 4 m × 5 m 20 m² | £39,000 – £47,500 | £45,500 – £59,500 | £58,000 – £76,500 |
| 5 m × 6 m 30 m² | £58,500 – £71,000 | £68,500 – £89,500 | £87,000 – £114,500 |
For a figure based on your own dimensions, use our guide-price tool.
Local to Swanley
Postcode districts we cover around Swanley include BR8. The same team covers Dartford (4 miles), Sevenoaks (9 miles), Gravesend (9 miles), Strood (13 miles), all within easy reach.
Homes across the South East range from Victorian terraces in the older town centres to large detached houses on the edges, so the right extension type varies street by street.
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
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
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Your questions about a timber frame extension in Swanley
Do I need building regulations approval in Swanley?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How long does a timber frame extension take to build in Swanley?
On site, typically 8 to 14 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.
Do you cover all of Swanley?
Yes. We cover Swanley and the surrounding parts of Kent. Site visits are free and there is no obligation.
Does a timber frame extension need planning permission?
The same planning rules apply as for any extension. If the cladding looks different from the house, permitted development’s matching-materials condition may mean an application is needed.
Is timber frame cheaper than brick?
It is similar overall. The frame can save time on site, but the cladding choice has a big effect on cost. Our guide range is about £1,960 to £3,810 per m² including VAT.
Book a free site visit in Swanley
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.