Two-storey wraparound extensions in Southsea

Before you start in Southsea, here's what applies.

Postcode districts: PO4 and PO5
County / area: Hampshire, 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: Portsmouth (1.1 miles), Gosport (1.9 miles), Cosham (4.5 miles)
Distance to Southampton: about 16 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 Southsea (PO4 and PO5) and the places around it, including Portsmouth (1.1 miles), Gosport (1.9 miles) and Cosham.

What it costs in Southsea

For budgeting in Southsea, 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. Steelwork for wide openings is the item most likely to move the figure; we'll know once the engineer has designed it.

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 Southsea

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 Southsea homes

Phasing the build

A wraparound touches two sides of the house at once, so the kitchen and often the rear rooms are out of use for part of the build. We plan the sequence so you keep a working kitchen and bathroom for as long as possible, or advise when moving out briefly makes sense.

Two roofs that meet

A wraparound needs the side roof and rear roof to join cleanly, often with a valley or hip where they meet. Getting pitches and ridge heights right keeps rainwater moving and avoids a bulky mass at the back corner, which neighbours and planners notice.

How we'd run your project

Look at the house
We start in Southsea with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Design and approvals
We draw the extension and check it against the rules for England, then apply for planning permission or a certificate of lawfulness, whichever fits.
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 Southsea

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.

Who handles building regulations for a project in Southsea?

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.

Which postcodes do you cover around Southsea?

We cover Southsea (PO4 and PO5) and nearby places including Portsmouth, Gosport and Cosham, plus the rest of Hampshire. The first site visit is free.

How much floor space does a wraparound extension add?

It depends on the width of the side plot and the depth at the rear. Our guide prices are based on a typical wraparound with an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space). Yours may be larger or smaller, and the measured survey shows what your plot can take.

Is a wraparound extension better than separate side and rear extensions?

Building both at once usually costs less than two separate projects, because you pay for one set-up, one scaffold, one roof junction and one set of approvals. It also lets the layout be designed as a whole. The trade-off is a larger single outlay and a longer build, often 16 to 24 weeks at this size.

Nearby

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

Other extensions in Southsea

All two-storey extension services in Southsea · Two-storey wraparound extensions across Hampshire

Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.