What is a side return extension?
A side return extension fills the narrow passage that runs alongside the back addition of many Victorian and Edwardian terraced houses. It widens a galley kitchen into a proper kitchen-diner, usually with a sloping glazed roof to keep the room bright.
How much does a side return extension cost in Penzance?
In Penzance, a side return extension typically costs £2,350–£3,350 per m² of floor area, including VAT at 20% (standard rate). For a typical 12 m² project that is roughly £28,000–£40,000. Prices in the South West sit near the national average for this kind of work, and the range for Penzance reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (8 m²) | £19,000–£27,000 |
| Typical project (12 m²) | £28,000–£40,000 |
| Larger project (17 m²) | £40,000–£57,000 |
| Rate per m² | £2,350–£3,350 |
Your quote will depend mainly on:
- Access through the house for materials
- Party wall surveyor fees
- Steel beams and propping of the back addition
- Moving drains and soil stacks
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 side return extension in Penzance?
Approvals for a side return extension in Penzance follow the rules for England. In England a side return infill is treated as a side extension. It may be permitted development if it is single-storey, no more than 4 metres high and no wider than half the original house, but not in a conservation area. Because side returns sit on the boundary, party wall notices are almost always needed.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
The work we manage on a side return extension:
- Foundations and drainage, including any build-over agreement
- Drawings and planning or permitted development check
- Glazed or solid roof with insulation
- Party wall advice and notices
- Steel beams to remove the side wall
- Floor levelling, heating and electrics
How long does it take?
The build itself usually takes 10 to 14 weeks on site. Design and approvals come first and typically take 3 to 4 months, depending on the approval route.
Building in Penzance
In parts of the South West, protected landscapes and conservation areas shape what can be built, so materials and roof forms are chosen carefully.
We work across Penzance and neighbouring areas such as Camborne, Redruth and Falmouth. Postcodes we cover in Penzance include TR18.
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 in place
We handle planning, building control and neighbour notices before work starts.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about side return extensions in Penzance
How much does a side return extension cost in Penzance?
In Penzance, a side return extension typically costs £2,350–£3,350 per m² of floor area, including VAT at 20% (standard rate). A typical 12 m² project comes to roughly £28,000–£40,000. Your fixed price depends on the survey and drawings.
Is a glass roof too hot or cold?
Modern solar-control double or triple glazing reduces glare and heat loss. Building regulations also limit how much glazing you can have unless the design shows it performs well enough.
Can I stay in the house?
Usually, though the kitchen will be out of action for several weeks. We plan a temporary kitchen area where possible.
How do you get materials in?
Mid-terrace houses often have no rear access, so materials come through the house. We protect floors and plan deliveries carefully.
Do you build side return extensions in Penzance?
Yes. We build side return extensions across Penzance, including postcodes TR18. Every project starts with a free home visit.