Two-storey wraparound extensions in Westbury

Westbury: the key facts for this kind of project.

Postcode districts: BA13
County / area: Wiltshire, England
Price region: South West England
Guide price: £124,000–£170,000 (£2,210–£3,040 per m²)
Approval route: Planning permission is needed: the side part takes it outside permitted development in England.
Nearest towns: Warminster (3.9 miles), Trowbridge (4.2 miles), Frome (6.2 miles)
Distance to Swindon: about 27 miles
First visit: Free, no obligation

About a two-storey wraparound extension

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.

We cover postcode district BA13 in and around Westbury, along with neighbouring Warminster, Trowbridge and Frome.

What it costs in Westbury

For budgeting in Westbury, allow around £124,000–£170,000 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 £2,210–£3,040 per m² including VAT for South West 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	£2,040–£2,800 per m²	£114,000–£156,500
Standard	£2,210–£3,040 per m²	£124,000–£170,000
Premium	£2,660–£3,650 per m²	£149,000–£204,000

Planning and building regulations in Westbury

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 Westbury 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.

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

Measure and listen
A visit to Westbury to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
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.
Build and hand over
We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.

Questions about two-storey wraparound extensions in Westbury

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

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

Our guide for South West England, which covers Westbury, is £2,210–£3,040 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 £124,000–£170,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Which postcodes do you cover around Westbury?

We cover Westbury (BA13) and nearby places including Warminster, Trowbridge and Frome, plus the rest of Wiltshire. 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.

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 Westbury, including:

Other extensions in Westbury

All two-storey extension services in Westbury · Two-storey wraparound extensions across Wiltshire

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