House extensions in Keynsham
From a small utility to a two-storey addition, we take on house extensions throughout Keynsham, starting with a free visit and a planning check.
- Postcode districtsBS31
- Price regionSouth West England (×1.02)
- Planning rulesEngland
- Site visitFree, no obligation
Areas we cover around Keynsham
We cover Keynsham and the postcode districts BS31. We also work in nearby Bath (6 miles), Nailsea (11 miles), Portishead (13 miles), Frome (15 miles), Clevedon (16 miles). For homes towards Gloucestershire, Kingswood is around 3 miles away.
Planning and building control in Keynsham
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 England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
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).
Which extension suits a Keynsham home?
South West homes range from terraced streets in the cities to stone cottages and bungalows in the countryside, and conservation areas are common in historic centres.
The types we would usually look at first for a home in Keynsham are pitched roof extensions, single-storey rear extensions and orangery extensions, depending on the garden and how the house is laid out.
Guide prices for Keynsham
Use these Keynsham guide prices to sense-check a budget; the guide-price tool narrows them to your own size, and the site visit turns them into a written figure.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Conservatory replacement extensions | 14 m² | £30,500 – £39,500 |
| Single-storey rear extensions | 20 m² | £41,500 – £53,500 |
| Kitchen extensions | 20 m² | £42,500 – £54,500 |
| Side return extensions | 11 m² | £26,500 – £34,000 |
| Double-storey extensions | 32 m² | £58,500 – £77,000 |
Choose an extension type
- Bedroom extensions · from £26,500
- Pitched roof extensions · from £22,500
- Bungalow extensions · from £26,500
- Kitchen extensions · from £27,500
- Extensions over a garage · from £24,000
- Porch extensions · from £4,050
- Double-storey extensions · from £38,500
- Building regulations for extensions · from £900
- Wraparound extensions · from £36,500
- Utility and boot room extensions · from £14,000
- Side return extensions · from £18,000
- Single-storey rear extensions · from £21,000
- Orangery extensions · from £30,500
- Side extensions · from £22,000
- Extension plans and drawings · from £1,200
- Planning permission for extensions · from £350
- Timber frame extensions · from £21,000
- Glass box extensions · from £30,500
- Annexe extensions · from £56,000
- Home office extensions · from £16,000
- Conservatory replacement extensions · from £20,000
- Flat roof extensions · from £21,000
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
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.
Questions about extensions in Keynsham
How much does an extension cost in Keynsham?
Using our South West England factor (×1.02), a standard-spec single-storey extension of 20 m² is a guide £41,500 to £53,500 including VAT, and a 32 m² two-storey extension £58,500 to £77,000. Your written price follows the survey.
Who do I contract with?
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.
How long does an extension take in Keynsham?
Usually 2 to 4 months of design and approvals, then 10 to 16 weeks on site for a single-storey extension or 16 to 24 weeks for two storeys.
Will my neighbours need to be told?
If you apply for planning or prior approval the council notifies them, and in England party wall notices may be needed for work near a shared boundary.
Book a free site visit in Keynsham
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.