Two-Storey Wraparound Extensions: Side and Rear

What you get

A two-storey wraparound extension suits a house with space both beside it and behind it, where you want to transform the layout rather than add a single room. You get one design for the whole L-shape, the planning application, structural design for the corner and the openings into the house, building regulations approval and the build, managed by us and carried out by vetted teams working under S&K.

It suits you if…

You want a large open-plan kitchen, dining and family room plus extra bedrooms
Your house has a side drive or garden as well as a reasonable rear garden
You plan to stay long term and would rather do one big project than two smaller ones
Your current layout has a narrow kitchen or a poor connection to the garden

Line drawing: existing house in outline, new work in brick, blue dashed line at first-floor level.

Design points that matter

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.

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.

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.

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.

Neighbours on both sides

The rear part affects the neighbour behind or alongside, while the side part affects the street and the neighbour to that side. We check light, outlook and overlooking on both, and plan party wall notices in England and Wales for any work on or near shared boundaries.

Planning and approvals by nation

England

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.

Wales

In Wales, a wraparound would have to pass both the side and rear tests to be permitted development: 10.5 m to the opposite side boundary, a 1 m set-back from the front and no more than 50% added width, plus the 4 m and 3 m rear depth limits and 10.5 m to the rear boundary. Many wraparounds therefore need a householder application, which costs £585.

Approval in Wales: Householder planning application: £585. Councils normally decide householder applications within 8 weeks.

Building regulations: Building regulations approval under the Welsh Approved Documents, which differ from England's in places (notably energy efficiency).

Scotland

In Scotland, a two-storey wraparound would need to be at least 10 m from every boundary to be permitted development under Class 1B, and not on an elevation fronting a road. That is rarely possible, so plan for a householder planning application, which costs £371 and is decided within two months, followed by a building warrant before work starts.

Approval in Scotland: Householder planning application: £371. Councils have two months to decide a local planning application.

Building standards: A building warrant from the council's building standards service before work starts, and a completion certificate at the end. Scotland uses its own Technical Handbooks.

Northern Ireland

In Northern Ireland, the permitted development allowance for two-storey extensions covers rear extensions of up to 3 m that stay 7 m from the rear boundary. A wraparound adds a side element on two floors, so it normally needs a planning application. The fee is £347 per dwelling, and councils aim for an average of 15 weeks for local applications.

Approval in Northern Ireland: Planning application for works to a house: £347. Councils aim to decide local applications within an average of 15 weeks; many take longer.

Building control: Building control approval from the local council under the Building Regulations (Northern Ireland), using the Technical Booklets.

Guide price

As a guide, a two-storey wraparound extension costs £120,500–£165,000 including VAT at 20% for an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space), based on West Midlands prices and our Standard spec; London and the South East are higher.

Guide prices by region
Region	Per m² of new floor	Typical project
London	£2,580–£3,540 per m²	£144,500–£198,000
South East England	£2,360–£3,250 per m²	£132,500–£181,500
East of England	£2,210–£3,040 per m²	£124,000–£170,000
South West England	£2,210–£3,040 per m²	£124,000–£170,000
West Midlands	£2,150–£2,950 per m²	£120,500–£165,000
East Midlands	£2,110–£2,890 per m²	£118,000–£162,000
North West England	£2,040–£2,800 per m²	£114,500–£157,000
Yorkshire and the Humber	£1,980–£2,710 per m²	£111,000–£152,000
North East England	£1,940–£2,660 per m²	£108,500–£148,500
Wales	£1,980–£2,710 per m²	£111,000–£152,000
Scotland	£2,020–£2,770 per m²	£113,000–£155,500
Northern Ireland	£1,890–£2,600 per m²	£106,000–£145,500

Typical project: an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space). Including VAT at 20%, Standard spec. Essential spec is about 8% less, Premium about 20% more. See all prices and fees or work out your own guide price.

What's included

Free site visit
Measured survey, priced in writing with the design stage
One design for the side and rear together
Planning drawings and application
Structural design for the corner and openings
Building regulations drawings and approval
Party wall notices in England and Wales where needed
A build sequence planned around your kitchen
The build, carried out by vetted teams working under S&K

How it works

Free site visit
We look at your house, the boundaries, access and drains, and talk through what you need the new space to do.
Design and approval
Measured survey and drawings, then planning permission or a lawful development certificate, depending on the rules where you live.
Engineering and fixed price
Structural calculations and building regulations approval, then a fixed build price in writing.
Build and sign-off
Vetted teams working under S&K build it, and we arrange the completion certificate.

Questions about two-storey wraparound extensions

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.

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.

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.

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.

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.

Related services

Two-storey side extensions

A two-storey side extension is a new two-floor addition built into the space beside your house, often over a driveway or side passage.

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Two-storey rear extensions

A two-storey rear extension is a new two-floor addition built onto the back of your house, usually giving a larger kitchen or living space on the ground floor and one or two bedrooms or a bathroom above.

Learn more

Structural engineering for two-storey extensions

Structural engineering for a two-storey extension involves calculating how the new floors, walls and roof carry their loads down to the ground, and designing the beams, lintels, foundations and ties into the existing house to suit.

Two-storey wraparound extensions