Annexe extensions in Truro
If you live in Truro and want more space without moving, an annexe extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.
- Guide price in TruroFrom £56,000 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsTR1
What is included
- Planning application describing ancillary use
- Separate or shared heating and hot water
- Kitchenette, shower room and bedroom finish
- Design for accessibility: level thresholds, wider doors, walk-in shower
Working in Truro
Postcode districts we cover around Truro include TR1. Nearby, we also take on projects in Falmouth (8 miles), Redruth (8 miles), Newquay (10 miles), Camborne (11 miles).
South West homes range from terraced streets in the cities to stone cottages and bungalows in the countryside, and conservation areas are common in historic centres.
Planning rules that apply in Truro
In England an annexe that stays part of the household and connects to the house is assessed as an extension, but its size usually takes it beyond permitted development, so a householder application describing the ancillary use is the normal route.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
What should I budget for an annexe extension in Truro?
Labour and material costs vary across the UK, so for Truro we use our South West England factor (×1.02). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Truro: £2,040 to £3,880 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Studio annexe 25 m² | £56,000 – £70,500 | £61,000 – £76,500 | £76,500 – £97,000 |
| One-bedroom annexe 35 m² | £71,000 – £89,500 | £85,500 – £107,500 | £107,000 – £136,000 |
| Larger annexe 45 m² | £91,500 – £115,000 | £110,000 – £138,000 | £137,500 – £174,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Questions people ask about annexe extensions
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Truro, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of Truro?
Yes. We cover Truro and the surrounding parts of Cornwall. Site visits are free and there is no obligation.
Will my neighbours in Truro be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Will an annexe affect council tax?
It can. Some annexes are assessed separately for council tax, with discounts or exemptions in some cases when occupied by a relative. Check with the Valuation Office Agency (England and Wales), your local assessor (Scotland) or Land & Property Services (Northern Ireland).
How much does an annexe extension cost?
Our guide range is about £2,040 to £3,880 per m² including VAT. A one-bedroom annexe of about 35 m² is typically £85,500 to £107,500 at standard spec in Truro.
Book a free site visit in Truro
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.