A single-storey extension is a new ground-floor room built onto your house, usually at the rear or side, with its own foundations, walls and roof, creating a bigger kitchen, living space or bedroom without moving home.
Thornaby-on-Tees sits within our coverage for a single-storey extension, as do neighbouring Stockton-on-Tees, Yarm and Billingham. Before giving a price we want to see the property: the condition of what's there now, the access, and anything that might need extra work. The guide range for Yorkshire and the Humber is £33,000–£70,000 including VAT, and your written quote will spell out exactly what that covers.
- Guide price
- £33,000–£70,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- TS5, TS16, TS17 and TS18
- Planning rules
- England
- Local area
- Stockton-on-Tees
- Survey
- Free, with a written quote
What should you budget for a single-storey extension in Thornaby-on-Tees?
Budgeting for a single-storey extension in Thornaby-on-Tees? The numbers below include VAT and are adjusted for Yorkshire and the Humber, where costs are about 6% below the national guide. The headline range is £33,000–£70,000. Nothing is final until we have measured up at a free survey and agreed the specification with you.
| Type of job | What it usually involves | Guide in Thornaby-on-Tees |
|---|---|---|
| Small extension (8–12m²) | A modest rear or side extension, such as a utility room or a slightly larger kitchen. | £20,500–£37,500 |
| Typical rear extension (15–25m²) | A kitchen-diner or family room with bifold doors and a rooflight or lantern. | £33,000–£70,000 |
| Large or wrap-around (30m² plus) | A wrap-around or wide rear extension, often with structural steelwork into the house. | £66,000–£122,000 |
Your price depends mostly on:
- Roof type, rooflights, lanterns and the amount of glazing
- Ground conditions, foundation depth and drains to divert
- Steelwork needed to open into the existing house
- Finishes, kitchen, flooring and heating specification
Scope of the work
- Groundworks, foundations and below-ground drainage
- Steel beams to open into the existing house
- Electrics and plumbing by qualified trades, with certificates
- Windows and external doors, including bifolds if chosen
- Plastering, screed floor and internal doors
- Building control inspections and completion certificate
Building in Thornaby-on-Tees
York has medieval timber-framed, Georgian and Victorian buildings, Harrogate has stone Victorian villas and terraces, and the Dales and Moors are built of limestone and sandstone, often under stone-slate or pantile roofs. Teesside towns within the county, such as Middlesbrough and Redcar, have Victorian red-brick terraces and post-war estates.
Dales and Moors properties often need lime pointing, roof repairs and window designs acceptable within a national park. Teesside brick terraces suit loft rooms and rear extensions, and estate homes commonly take garage conversions.
That mix of housing shapes how we approach a single-storey extension in Thornaby-on-Tees: the age and construction of your home affect the materials, the method and, in the end, the price.
Do you need permission in Thornaby-on-Tees?
For anyone in Thornaby-on-Tees, the relevant framework is England's. The summary below is general, so we always contact the council about your address before putting a price in writing.
In England, many single-storey rear extensions are permitted development: typically up to 3 m deep on a semi-detached or terraced house and 4 m on a detached house, no more than 4 m high, and covering no more than half the land around the original house. Larger rear extensions can go through the prior approval process. Side extensions, flats, listed buildings, conservation areas and homes where permitted development rights have been removed need planning permission.
Building Regulations approval is needed for almost every extension, covering foundations, structure, insulation, drainage, ventilation and fire safety. If the work is on or near a shared wall or boundary, the Party Wall etc. Act 1996 may apply.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
What happens after you get in touch?
We look at the job
We begin by looking at the job in person. During the free survey we discuss options, materials and budget for a single-storey extension, and photograph or measure anything the quote needs to reflect.
Quote in writing
The quote arrives in writing, not over the phone. It covers the full scope, the finishes you've chosen, any exclusions and the payment schedule, with a fixed price tied to that specification.
Dates and permissions
With the quote agreed, we book the work in and handle preparation: permissions where needed, building control notifications, material orders and access arrangements for your Thornaby-on-Tees property.
On site to finish
On site, the agreed plan is followed and any change is put in writing first. At completion we do a final clean, go through the snagging list with you and leave you with the relevant documents.
Why homeowners choose us
Frequently asked questions
What does a typical extension build look like week by week?
A typical single-storey extension follows the same order: clearing the site and digging foundations, building walls up to roof level, then fitting the roof and windows to make it weathertight. Electrics, plumbing, insulation and plastering follow. The last stage is opening into the house, laying the screed and fitting doors and finishes. Building control inspects at key stages, and we book those visits for you.
How long does a single-storey extension take to build?
A single-storey extension usually takes 10–16 weeks on site, from digging foundations to final plastering. Bad weather, deep foundations or a complex roof can add time. Before work starts, allow several weeks for drawings, structural calculations and building control approval, and longer if planning permission is needed. We give you a stage-by-stage programme with your quote so you know what happens each week.
How long will a single-storey extension take?
On a typical home, allow 10–16 weeks on site. Larger projects, older buildings and extra work found once things are opened up can extend that, while simpler jobs may be shorter. Your quote includes an estimate of time on site, and your point of contact keeps you updated on the programme as the work progresses.
Which postcodes in Thornaby-on-Tees do you cover?
We cover TS5, TS16, TS17 and TS18, along with the rest of North Yorkshire. If your postcode is not listed, get in touch anyway: our coverage is UK-wide, and we can usually arrange a survey wherever you live. Enter your postcode in the guide-price tool or contact form and we will confirm.
What is the Party Wall Act and does it apply to me?
The Party Wall etc. Act 1996 applies in England and Wales only. In England and Wales, it requires you to give notice to neighbours before certain work on or near a shared wall, such as digging foundations within 3m of their building and deeper than its footings. Neighbours can agree or appoint a surveyor. Scotland and Northern Ireland have no equivalent Act, though general rights still apply. We identify whether notices are needed during the survey.
Near Thornaby-on-Tees
Addresses in TS5, TS16, TS17 and TS18 are all covered for Thornaby-on-Tees, along with Stockton-on-Tees, Yarm and Billingham close by. Give us your postcode when you get in touch and we will confirm the details.