Keynsham, Somerset
Two-storey rear extension in Keynsham
Two-storey rear extension in Keynsham: a larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. We measure the house, show you what the rules allow, price it in writing and build it.
Keynsham and its postcode districts BS31 are part of our Somerset coverage. In Keynsham, a two-storey rear extension is worth comparing with the cost of moving once stamp duty, agents' and legal fees are counted.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a two-storey rear extension cost in Keynsham?
A two-storey rear extension in Keynsham is priced at £1,870–£2,810 per square metre including VAT as a guide, before kitchen fit-out and fees. South West prices run slightly above our West Midlands baseline; natural stone to match the house is the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m × 5 m footprint, two floors (30 m²) | £56,000–£84,000 |
| 4 m × 6 m footprint, two floors (48 m²) | £90,000–£135,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a two-storey rear extension in Keynsham?
Planning for a two-storey rear extension in Keynsham follows the English householder rules.
England's rules allow a rear extension of more than one storey without an application only when it is no deeper than 3 metres and at least 7 metres from the boundary opposite the rear wall, and never on designated land. Most two-storey schemes need householder planning permission.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. Before any drawing we look up the property's history with the council, because earlier extensions and removed rights change the answer.
What are homes in Keynsham like to extend?
Stone-built and rendered houses are common around Keynsham, so matching the walling is a design decision in its own right: natural stone, reconstituted stone or a render finish across old and new.
How a two-storey rear extension in Keynsham comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Two-storey rear extensions near Keynsham
Neighbouring places we cover include Kingswood (2.7 miles) and Mangotsfield (5.1 miles).
- Two-storey rear extension in Kingswood
- Two-storey rear extension in Mangotsfield
- Two-storey rear extension in Bristol
- Two-storey rear extension in Bishopsworth
- Two-storey rear extension in Bath
Other work in Keynsham:
FAQ
Two-storey rear extension questions in Keynsham
How long does a rear extension take to build in Keynsham?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
How much does a two-storey rear extension cost in Keynsham?
As a guide, £1,870–£2,810 per square metre including VAT for a standard specification. For example, 3 m × 5 m footprint, two floors (30 m²): about £56,000–£84,000 at that rate. Your written price follows the survey.
Is two-storey cheaper per square metre than single-storey?
Usually yes, because the foundations and roof are shared across twice the floor area. The total cost is higher.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.