Two-storey wraparound extensions in Portslade

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

Postcode districts: BN41
County / area: East Sussex, England
Price region: South East England
Guide price: £132,500–£181,500 (£2,360–£3,250 per m²)
Approval route: Planning permission is needed: the side part takes it outside permitted development in England.
Nearest towns: Hove (2.3 miles), Shoreham-by-Sea (2.6 miles), Brighton (3.5 miles)
Distance to Brighton: about 3.5 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 Portslade (BN41) and the places around it, including Hove (2.3 miles), Shoreham-by-Sea (2.6 miles) and Brighton.

What it costs in Portslade

For budgeting in Portslade, allow around £132,500–£181,500 for a two-storey wraparound extension with an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space). That's based on £2,360–£3,250 per m² including VAT for South East England. 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	£2,180–£2,990 per m²	£122,000–£167,000
Standard	£2,360–£3,250 per m²	£132,500–£181,500
Premium	£2,840–£3,890 per m²	£159,000–£218,000

Planning and building regulations in Portslade

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 Portslade homes

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.

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.

How we'd run your project

Start at your house
We come to your home in Portslade, measure up, check the ground floor walls and roof structure, and note anything near the boundaries.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
Finish and certify
Second fix, plastering and making good, then building control's final inspection and the completion paperwork.

Questions about two-storey wraparound extensions in Portslade

Do I need planning permission for a two-storey wraparound extension in Portslade?

Portslade 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.

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.

How much does a two-storey wraparound extension cost in Portslade?

Our guide for South East England, which covers Portslade, is £2,360–£3,250 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 £132,500–£181,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

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

We also cover places near Portslade, including:

Other extensions in Portslade

All two-storey extension services in Portslade · Two-storey wraparound extensions across East Sussex

Ready to talk it through? Call us or send the form and we'll arrange a visit to your home in Portslade.