Cornwall
Two-storey rear extensions in Cornwall
A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. Rear extensions in Cornwall: we cover 10 towns including Redruth, Falmouth and St Austell, with design, approvals and the build under one contract.
In Cornwall we check the neighbours' rear windows first, because the upper floor is where most two-storey schemes win or lose planning. 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 two-storey rear extension cost in Cornwall?
A two-storey rear extension in Cornwall 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 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission in Cornwall?
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.
Where in Cornwall do we work?
FAQ
Questions people ask
Does a two-storey rear extension need planning permission?
Almost always. England and Northern Ireland allow 3 metres without an application only if at least 7 metres remains to the rear boundary; Wales and Scotland are similar or stricter.
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.
Can I add an en-suite upstairs?
Yes. We plan the soil pipe route early so the bathroom sits where drainage works without boxing through the room below.
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.