Two-storey wraparound extensions in Seaham

Useful details for planning a two-storey wraparound extension in Seaham.

Postcode districts: SR7
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: Ryhope (2.4 miles), Hetton-le-Hole (4.4 miles), Houghton-le-Spring (4.7 miles)
Distance to Darlington: about 23.2 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.

Around Seaham we also work in Ryhope, Hetton-le-Hole and Houghton-le-Spring, and across the rest of County Durham. Postcode district in and near Seaham: SR7.

What it costs in Seaham

Expect a two-storey wraparound extension in Seaham to land somewhere 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). Our North East England guide rate is £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 Seaham

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 Seaham 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

Measure and listen
A visit to Seaham to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Get it approved
Once you're happy with the design we submit it to the council for Seaham and deal with any questions from the planning officer.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.

Questions about two-storey wraparound extensions in Seaham

Who handles building regulations for a project in Seaham?

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 much does a two-storey wraparound extension cost in Seaham?

Our guide for North East England, which covers Seaham, is £1,940–£2,660 per m² including VAT. A typical project with an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space) comes to about £108,500–£148,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

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.

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.

Can a wraparound extension be part single, part two-storey?

Yes. Many wraparounds keep the rear part single storey with roof lights over the kitchen and put the two-storey part to the side. This can reduce the effect on neighbours and the cost. We set out both options at the design stage, so you can compare floor space against price before choosing.

Nearby

Close to Seaham? We work across the area, including:

Other extensions in Seaham

All two-storey extension services in Seaham · Two-storey wraparound extensions across County Durham

The quickest next step is a visit. We'll look at your house in Seaham and give you an honest view of the options.