Two-storey wraparound extensions in Cardiff

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

Postcode districts: CF10, CF11 and CF24
County / area: Cardiff and the Vale of Glamorgan, Wales
Price region: Wales
Guide price: £111,000–£152,000 (£1,980–£2,710 per m²)
Approval route: Usually needs planning permission, because the combined side and rear works rarely meet every permitted development test.
Nearest towns: Llandaff (1.9 miles), Whitchurch (Cardiff and the Vale of Glamorgan) (2.8 miles), Penarth (2.9 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 Cardiff (CF10, CF11 and CF24) and the places around it, including Llandaff (1.9 miles), Whitchurch (Cardiff and the Vale of Glamorgan) (2.8 miles) and Penarth.

What it costs in Cardiff

In Wales, which includes Cardiff, we'd expect a two-storey wraparound extension to cost around £111,000–£152,000 for an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space), or £1,980–£2,710 per m² including VAT. We'll give you a written design-stage price first, then a fixed build price once the drawings are agreed.

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	£1,820–£2,500 per m²	£102,000–£140,000
Standard	£1,980–£2,710 per m²	£111,000–£152,000
Premium	£2,370–£3,260 per m²	£133,000–£182,500

Planning and building regulations in Cardiff

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).

Design points for Cardiff homes

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.

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

Free site visit
We visit your home in Cardiff, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Detail and price
Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.

Questions about two-storey wraparound extensions in Cardiff

How long does a two-storey wraparound extension take?

Allow 4 to 8 weeks for survey and design, then the approval period (councils normally decide householder applications within 8 weeks), 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.

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

Cardiff is in Wales, so Wales planning rules apply. Usually needs planning permission, because the combined side and rear works rarely meet every permitted development test. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.

Who handles building regulations for a project in Cardiff?

We handle it as part of the project. What's needed in Wales: building regulations approval under the Welsh Approved Documents, which differ from England's in places (notably energy efficiency). We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.

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.

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.

Nearby

Nearby towns we cover for two-storey wraparound extensions:

Other extensions in Cardiff

All two-storey extension services in Cardiff · Two-storey wraparound extensions across Cardiff and the Vale of Glamorgan

Book a free site visit in Cardiff and we'll tell you what's possible, what approvals you need and what the design stage would cost.