Cornwall
Rear extensions for terraced houses in Cornwall
Rear and side return extensions for terraces, with access through the house and two neighbours. Rear extensions in Cornwall: we cover 10 towns including Redruth, Falmouth and St Austell, with design, approvals and the build under one contract.

On a Redruth terrace both neighbours usually need party wall notices or agreement, so we talk to them early. Stone-built and rendered houses are common around Cornwall, 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 much does a terraced house rear extension cost in Cornwall?
A terraced house rear extension in Cornwall is priced at £2,130–£3,430 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 wide × 4.5 m deep (13.5 m²) | £29,000–£46,500 |
| 3 m wide × 6 m deep (18 m²) | £38,500–£62,000 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission in Cornwall?
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.
Because rear extensions often sit on or near the boundary, the Party Wall etc. Act 1996 usually applies in England. Notices go out one or two months before work depending on the type of work, and a surveyor's award is only needed if a neighbour does not consent.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent.
Where in Cornwall do we work?
FAQ
Questions people ask
Can you build without side access?
Yes. Materials come through the house in protected runs or over the roof by crane on tight sites.
Do both neighbours need party wall notices?
Usually yes in England and Wales, because the extension often sits on or near both boundaries.
How deep can I go on a terrace?
3 metres under permitted development in England, or up to 6 metres with prior approval outside designated land.
Do you cover all of Cornwall?
We cover 10 towns and districts in Cornwall, including Redruth, Falmouth and St Austell.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.