Side extensions in Thornaby-on-Tees
A side extension in Thornaby-on-Tees starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in Thornaby-on-TeesFrom £20,000 inc VAT
- PlanningSingle storey can be permitted development
- Build time10–18 weeks on site
- Postcode districtsTS17
When a side extension makes sense
- Detached and semi-detached houses with side land
- Homes needing a utility, study or ground-floor bedroom
- Houses where the rear garden is small
Local to Thornaby-on-Tees
Our survey diary covers Thornaby-on-Tees, including TS17. The same team covers Stockton-on-Tees (3 miles), Yarm (3 miles), Billingham (4 miles), Darlington (10 miles), all within easy reach.
The North East has many brick terraces, colliery-era housing and post-war semis, with rear extensions and kitchen extensions the most common requests.
Guide prices for Thornaby-on-Tees
Labour and material costs vary across the UK, so for Thornaby-on-Tees we use our North East England factor (×0.91). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Thornaby-on-Tees: £1,590 to £3,090 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £20,000 – £24,500 | £22,000 – £29,000 | £28,000 – £37,500 |
| 3 m × 6 m 18 m² | £28,500 – £34,500 | £33,500 – £43,500 | £42,500 – £56,000 |
| 3 m × 8 m 24 m² | £38,000 – £46,000 | £44,500 – £58,000 | £56,500 – £74,500 |
Try the guide-price tool to see a range for your own size and finish.
Planning rules that apply in Thornaby-on-Tees
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
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.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
How the project works
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
We visit your Thornaby-on-Tees home, measure up, talk through what you want and check the planning position.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Side extension questions answered
Do you cover all of Thornaby-on-Tees?
Yes. We cover Thornaby-on-Tees and the surrounding parts of County Durham. Site visits are free and there is no obligation.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Thornaby-on-Tees, 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 I need building regulations approval in Thornaby-on-Tees?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How close to the boundary can I build?
It depends on height. In England, within 2 m of a boundary the eaves must not exceed 3 m under permitted development. Building on the boundary is possible but brings party wall and maintenance access issues we plan for.
How much does a side extension cost?
Our guide range is about £1,590 to £3,090 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £33,500 to £43,500 in Thornaby-on-Tees.
Book a free site visit in Thornaby-on-Tees
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.