What is a wraparound extension?
A wraparound extension combines a side return and a rear extension into one L-shaped addition. It gives the largest possible ground floor, often creating an open-plan kitchen, dining and living space across the whole width of the house.
How much does a wraparound extension cost in Cornwall?
In Cornwall, a wraparound extension typically costs £2,250–£3,250 per m² of floor area, including VAT at 20% (standard rate). For a typical 28 m² project that is roughly £63,000–£91,000. Building costs in the South West are close to the UK average, so the figures for Cornwall are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (20 m²) | £45,000–£65,000 |
| Typical project (28 m²) | £63,000–£91,000 |
| Larger project (39 m²) | £88,000–£127,000 |
| Rate per m² | £2,250–£3,250 |
The main things that change the cost:
- Total footprint and the amount of glazing
- Steelwork and propping of the existing house
- Access for materials on terraced streets
- Kitchen and flooring specification
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a wraparound extension in Cornwall?
Here is how the rules work for a wraparound extension in England. In England a wraparound extension combines side and rear elements, which normally takes it outside permitted development, so a householder planning application is made.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
From survey to sign-off, the job normally involves:
- Design and planning application
- Structural engineer’s design for steels and supports
- Building control completion
- Foundations and drainage
- Underfloor heating option, electrics and plastering
- Party wall notices and surveyor liaison
How long does it take?
Expect 12 to 18 weeks on site. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Cornwall
The South West mixes stone and render cottages with post-war and newer estates, and local materials matter more here when matching an extension.
Towns we cover in Cornwall include Redruth, Falmouth, St Austell, Truro, Camborne and Newquay.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about wraparound extensions in Cornwall
Who approves a wraparound extension in Cornwall?
Planning matters in Cornwall go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
How long does it take to build?
Around 12 to 18 weeks on site after approvals. Design, planning and party wall matters usually take 3 to 4 months beforehand.
What about the old back addition?
The side wall of the back addition is usually removed and replaced with a steel beam, so the old kitchen joins the new space.
How much does a wraparound extension cost in Cornwall?
In Cornwall, a wraparound extension typically costs £2,250–£3,250 per m² of floor area, including VAT at 20% (standard rate). A typical 28 m² project comes to roughly £63,000–£91,000. Your fixed price depends on the survey and drawings.
Can we keep a separate living room?
Yes. Many clients keep the front room separate and open up only the back of the house.