Two-storey extensions in Thornbury
Homeowners in Thornbury can use us for the whole project or just the drawings and approvals. Start with a free visit.
Thornbury at a glance
- Postcode districts
- BS35
- Area
- Gloucestershire, England
- Price region
- South West England
- Nearest towns
- Stoke Gifford (6.4 miles), Yate (6.4 miles), Severn Beach (7 miles), Mangotsfield (8.4 miles)
- Distance to Gloucester
- about 21.3 miles
- Approvals
- Two-storey rear: up to 3 m deep and 7 m from the rear boundary under permitted development. Side, wraparound and front: planning permission.
We cover postcode district BS35 in and around Thornbury, along with neighbouring Stoke Gifford, Yate and Severn Beach.
Extensions available in Thornbury
Two-storey rear extensions
Thornbury guide price from £57,500, Standard spec.
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Two-storey side extensions
For homes in Thornbury: typical guide from £88,500.
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Two-storey wraparound extensions
For homes in Thornbury: typical guide from £124,000.
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Part single, part two-storey extensions
From £74,000 in Thornbury. Free visit to firm it up.
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Extensions over a garage
Design, approvals and build for Thornbury homes. Guide from £32,500.
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First-floor extensions
Thornbury guide price from £26,000, Standard spec.
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Two-storey extensions for semi-detached houses
Our South West England guide starts at £57,500 for this type.
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Two-storey extensions for detached houses
From £88,500 in Thornbury. Free visit to firm it up.
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Kitchen extensions with bedrooms above
Thornbury guide price from £57,500 (before kitchen units), Standard spec.
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Extra bedroom and en-suite extensions
Guide from £57,500 (plus en-suite) in Thornbury, including VAT.
Learn moreWhich type suits your house?
Start with what you need the space for. Bedrooms and an en-suite upstairs with a bigger kitchen below is the classic two-storey brief, but in Thornbury we also design annexes, home offices and bedrooms over garages.
Also available in Gloucestershire
- Two-storey front extensions
- Two-storey extensions for end-of-terrace houses
- Two-storey annexe extensions
- Garage conversions with a room above
- Two-storey extension plans and drawings
- Planning permission for two-storey extensions
- Structural engineering for two-storey extensions
- Building regulations for two-storey extensions
- Party wall notices for extensions
- Design and build two-storey extensions
Rules for Thornbury
Thornbury is in England. Two-storey rear: up to 3 m deep and 7 m from the rear boundary under permitted development. Side, wraparound and front: planning permission. 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.
The full England rules explained
Questions about extensions in Thornbury
Do you cover Thornbury?
Yes. We cover Thornbury (BS35) and the surrounding area, including Stoke Gifford and Yate. The first site visit is free.
What does a two-storey extension cost in Thornbury?
Using our South West England guide, a two-storey rear extension with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) is about £57,500–£78,000 including VAT. An extension over a garage is about £32,500–£47,500.
Which other places near Thornbury do you cover?
Everywhere around it, including Stoke Gifford (6.4 miles), Yate (6.4 miles) and Severn Beach (7 miles), and the rest of Gloucestershire.