Thornbury, Bristol and South Gloucestershire
Two-storey rear extension in Thornbury
Thinking about a two-storey rear extension in Thornbury? A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. Our team handles the drawings, the planning route and the build, and your contract is with one company throughout.
We cover Thornbury (BS35) as part of our Bristol and South Gloucestershire work. In Bristol and South Gloucestershire we check the neighbours' rear windows first, because the upper floor is where most two-storey schemes win or lose planning.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a two-storey rear extension cost in Thornbury?
Guide prices for a two-storey rear extension in Thornbury start from our South West England rate of £1,870–£2,810 per square metre, including VAT. 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 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a two-storey rear extension in Thornbury?
Planning for a two-storey rear extension in Thornbury follows the English householder rules.
A two-storey rear extension can be permitted development in England only if it projects no more than 3 metres, stays at least 7 metres from the rear boundary, matches the existing roof pitch and has obscure-glazed upper side windows. In practice most double-storey rear extensions go through a householder planning application.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.
What are homes in Thornbury like to extend?
Thornbury has Victorian terraces nearer the centre and post-war semis on the edges. Sloping gardens are frequent, which affects floor levels and steps down to the patio.
How a two-storey rear extension in Thornbury comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Two-storey rear extensions near Thornbury
From Thornbury, the nearest places we also cover are Stoke Gifford (6.4 miles) and Yate (6.4 miles).
- Two-storey rear extension in Stoke Gifford
- Two-storey rear extension in Yate
- Two-storey rear extension in Chepstow
- Two-storey rear extension in Mangotsfield
- Two-storey rear extension in Dursley
Other work in Thornbury:
FAQ
Two-storey rear extension questions in Thornbury
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
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.
Do you handle building control in Thornbury?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
Can you match the brick or stone on my Thornbury house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
Do I need planning permission for a rear extension in Thornbury?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.