Two-storey extensions for end-of-terrace houses in Cornwall
Our two-storey extensions for end-of-terrace houses service covers the whole of Cornwall. Choose your town below or book a free visit straight away.
Cornwall at a glance
- Nation
- England
- Price region
- South West England
- Postcode areas
- PL, TR
- Towns covered
- 10 listed below, plus surrounding villages
- Approval route
- Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
- Site visits
- Free, no obligation
What a two-storey extension for an end-of-terrace house involves
This service suits you if you own an end-of-terrace house with land to the side or a reasonable rear garden.
The main places we list in Cornwall are Redruth (TR5), Falmouth (TR10), St Austell (PL23), Truro (TR1), Camborne (TR14) and Newquay (PL28). We cover the villages in between too.
Guide price in South West England
A guide price for Cornwall: around £88,500–£119,000 for a 3 m × 7 m footprint on two floors (42 m² of new floor space). That works out at £2,110–£2,830 per m² of new floor space, including VAT at 20%. Design fees, structural calculations and approval fees are separate and listed on our prices page.
| Spec | Per m² | Typical project |
|---|---|---|
| Essential | £1,940–£2,610 per m² | £81,500–£109,500 |
| Standard | £2,110–£2,830 per m² | £88,500–£119,000 |
| Premium | £2,530–£3,400 per m² | £106,500–£143,000 |
Rules in England
In England, a two-storey side extension on an end-of-terrace house always needs planning permission, costing £548 (or £575 for applications made from 8 December 2026). A two-storey rear extension can be permitted development within 3 m of the original rear wall and 7 m from the rear boundary. On a corner plot, nothing can go beyond a side wall that fronts a highway under permitted development.
Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.
The Party Wall etc. Act 1996 applies, so notices may be needed for work on or near a shared wall or boundary.
Getting the design right
Corner plots
Many end-of-terrace houses sit on corners, where the side wall faces a road. In England nothing can be built beyond a side wall that fronts a highway under permitted development, and councils guard open corners, so we keep a gap to the pavement and design the side wall as a second front.
Continuing the terrace roof
A side extension on an end-of-terrace house usually continues the roofline of the row, so the pitch, eaves height and tiles must match. A small step down in the ridge and a set-back at the front often help the extension read as an addition rather than an extra house.
How we work in Cornwall
Start at your house
We come to your home in Cornwall, measure up, check the ground floor walls and roof structure, and note anything near the boundaries.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in England before drawing in detail.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
Finish and certify
Second fix, plastering and making good, then building control's final inspection and the completion paperwork.
Towns we cover in Cornwall
Two-storey extensions for end-of-terrace houses in Cornwall: questions
How much does a two-storey extension for an end-of-terrace house cost in Cornwall?
In South West England our guide is £2,110–£2,830 per m² including VAT, so about £88,500–£119,000 for a 3 m × 7 m footprint on two floors (42 m² of new floor space). Essential and Premium specs move that by roughly 8% down or 20% up.
Can an end-of-terrace house have a wraparound extension?
Yes, if there is room to the side and rear. It combines a side extension over the open plot with a rear extension, and it always needs planning permission in England. It gives a large open-plan ground floor, but it also affects the attached neighbour and the street, so we test it carefully.
Are old terrace foundations strong enough to extend next to?
Usually, but they need checking. Older terraces often have shallow brick footings, and a new two-storey extension sits on deeper, modern foundations alongside them. The structural engineer designs the junction so the two can move slightly without cracking, and we dig trial holes to see what is there before the design is fixed.
Can I build a two-storey side extension on a corner plot?
Often, but it needs planning permission and careful design. Councils protect the openness of corners and the view along the road, so they usually expect a gap to the pavement, a set-back from the front and a side wall with windows rather than a blank wall. We check local guidance and nearby examples first.
Will I need planning permission in Cornwall?
Cornwall is in England. Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
Neighbouring areas
- Two-storey extensions for end-of-terrace houses in Devon
- Two-storey extensions for end-of-terrace houses in Swansea and Neath Port Talbot
- Two-storey extensions for end-of-terrace houses in Dyfed
- Two-storey extensions for end-of-terrace houses in Cardiff and the Vale of Glamorgan
All extension services in Cornwall · About two-storey extensions for end-of-terrace houses
Ready to see what a second storey could do for your home?
Book a free site visit. We'll look at your house, talk through options and explain the approvals you'd need, then price the design stage in writing.