Two-storey wraparound extensions in Thornaby-on-Tees

What we'd confirm first for a project in Thornaby-on-Tees.

Postcode districts: TS17
County / area: County Durham, England
Price region: North East England
Guide price: £108,500–£148,500 (£1,940–£2,660 per m²)
Approval route: Planning permission is needed: the side part takes it outside permitted development in England.
Nearest towns: Stockton-on-Tees (2.5 miles), Yarm (3.1 miles), Billingham (3.9 miles)
Distance to Darlington: about 10.1 miles
First visit: Free, no obligation

About a two-storey wraparound extension

A two-storey wraparound extension is an L-shaped addition that extends both the side and the rear of your house, on two floors. It gives one of the largest gains in floor space of any extension, typically a big open-plan kitchen and living area below and two or more bedrooms or bathrooms above. In England it needs planning permission, because the side part is more than one storey.

We cover postcode district TS17 in and around Thornaby-on-Tees, along with neighbouring Stockton-on-Tees, Yarm and Billingham.

What it costs in Thornaby-on-Tees

In North East England, which includes Thornaby-on-Tees, we'd expect a two-storey wraparound extension to cost around £108,500–£148,500 for an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space), or £1,940–£2,660 per m² including VAT. Kitchens, bathroom fittings and flooring are priced separately so you can compare like with like.

Spec	Per m²	An L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space)
Essential	£1,780–£2,440 per m²	£99,500–£137,000
Standard	£1,940–£2,660 per m²	£108,500–£148,500
Premium	£2,320–£3,190 per m²	£130,000–£178,500

Planning and building regulations in Thornaby-on-Tees

In England, a two-storey wraparound extension needs householder planning permission, because any extension beyond a side wall must be single storey to be permitted development. The application costs £548 (or £575 for applications made from 8 December 2026). Councils weigh the side part against the street scene and the rear part against neighbours' light and outlook, and should decide within 8 weeks of validation.

Approval in England: 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.

Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.

Design points for Thornaby-on-Tees homes

Daylight to the middle

A deep L-shaped plan can leave the middle of the ground floor dark, because the old rear rooms are now enclosed. We use wide rear openings, a well-placed stair and, where part of the extension is single storey, roof lights, while keeping total glazing within the Part L allowance.

The corner post

At the outside corner of the L, there is no existing wall to carry the floor above. Opening the ground floor fully usually means a steel frame or a corner post, and the engineer's design sets how slim it can be. We decide early whether you want a clear corner or a visible post.

How we'd run your project

Free site visit
We visit your home in Thornaby-on-Tees, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.

Questions about two-storey wraparound extensions in Thornaby-on-Tees

Do I need planning permission for a two-storey wraparound extension in Thornaby-on-Tees?

Thornaby-on-Tees is in England, so England planning rules apply. Planning permission is needed: the side part takes it outside permitted development in England. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.

Who handles building regulations for a project in Thornaby-on-Tees?

We handle it as part of the project. What's needed in England: building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.

How long does a two-storey wraparound extension take?

Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.

Can I stay at home during a wraparound extension?

Many people do, but a wraparound affects two sides of the house and usually the kitchen, so there will be weeks without a full kitchen. We plan a temporary kitchen, keep a route through the house and seal off the work area. For some families, moving out while the rear wall is opened up is easier.

Does a wraparound extension need steel?

Almost always. Opening the corner of the house and the old rear wall to make one open-plan space means steel beams, and often a steel post or frame at the outside corner. The structural engineer sizes these, and the steel is ordered once the design is fixed, which is one reason a wraparound needs careful sequencing.

Nearby

We also cover places near Thornaby-on-Tees, including:

Other extensions in Thornaby-on-Tees

All two-storey extension services in Thornaby-on-Tees · Two-storey wraparound extensions across County Durham

Tell us about your house in Thornaby-on-Tees and we'll call you back to arrange a free, no-obligation visit.