Home extensions in Penzance
We design and build house extensions for homes in Penzance and the surrounding Cornwall area, with guide prices adjusted for the region.
- Postcode districtsTR18
- Price regionSouth West England (×1.02)
- Planning rulesEngland
- Site visitFree, no obligation
What works best for Penzance houses?
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.
For many houses here, pitched roof extensions, orangery extensions or annexe extensions gives the most useful space for the budget.
Penzance extension prices at a glance
Every figure below is a guide for Penzance, adjusted for South West England build costs (×1.02) and including VAT. Design and council fees are shown separately on each page.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Side return extensions | 11 m² | £26,500 – £34,000 |
| Orangery extensions | 16 m² | £45,500 – £57,500 |
| Kitchen extensions | 20 m² | £42,500 – £54,500 |
| Double-storey extensions | 32 m² | £58,500 – £77,000 |
| Extensions over a garage | 12 m² | £25,500 – £33,500 |
| Wraparound extensions | 25 m² | £58,500 – £74,000 |
| Single-storey rear extensions | 20 m² | £41,500 – £53,500 |
Do extensions in Penzance need planning permission?
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.
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).
All extension types we build in Penzance
- Pitched roof extensions · from £22,500
- Double-storey extensions · from £38,500
- Home office extensions · from £16,000
- Single-storey rear extensions · from £21,000
- Planning permission for extensions · from £350
- Kitchen extensions · from £27,500
- Extension plans and drawings · from £1,200
- Glass box extensions · from £30,500
- Annexe extensions · from £56,000
- Wraparound extensions · from £36,500
- Bungalow extensions · from £26,500
- Porch extensions · from £4,050
- Utility and boot room extensions · from £14,000
- Extensions over a garage · from £24,000
- Bedroom extensions · from £26,500
- Side return extensions · from £18,000
- Building regulations for extensions · from £900
- Conservatory replacement extensions · from £20,000
- Flat roof extensions · from £21,000
- Side extensions · from £22,000
- Orangery extensions · from £30,500
- Timber frame 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
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
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
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions about extensions in Penzance
How much does an extension cost in Penzance?
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.
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.
Can I get a price before anyone visits?
Yes. This page shows guide prices adjusted for Penzance, and the guide-price tool gives a range for your own size and finish in about a minute.
How long does an extension take in Penzance?
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.
Book a free site visit in Penzance
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.