Two-storey side extensions in Rhiwbina

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

Postcode districts: CF14 and CF15
County / area: Cardiff and the Vale of Glamorgan, Wales
Price region: Wales
Guide price: £79,000–£106,500 (£1,890–£2,530 per m²)
Approval route: Can be permitted development in Wales if it is 10.5 m from the side boundary, set back 1 m from the front and doesn't widen the house by more than half; otherwise planning permission.
Nearest towns: Whitchurch (Cardiff and the Vale of Glamorgan) (1.2 miles), Thornhill (1.3 miles), Llandaff (2.4 miles)
Distance to Cardiff: about 3.6 miles
First visit: Free, no obligation

About a two-storey side extension

A two-storey side extension suits a detached or semi-detached house with a side garden, driveway or garage wide enough to build on. You get a design that sits comfortably on the street, a planning application or permitted development check depending on your nation, structural design, building regulations approval and the build itself. We manage the whole process, and the work is carried out by vetted teams working under S&K.

We cover Rhiwbina (CF14 and CF15) and the places around it, including Whitchurch (Cardiff and the Vale of Glamorgan) (1.2 miles), Thornhill (1.3 miles) and Llandaff.

What it costs in Rhiwbina

Guide prices for two-storey side extensions in Wales are around £1,890–£2,530 per m² of new floor space, including VAT. For a typical project with a 3 m × 7 m footprint on two floors (42 m² of new floor space), that's roughly £79,000–£106,500. Professional fees for drawings and the structural engineer are listed separately on our prices page.

Spec	Per m²	A 3 m × 7 m footprint on two floors (42 m² of new floor space)
Essential	£1,740–£2,330 per m²	£73,000–£98,000
Standard	£1,890–£2,530 per m²	£79,000–£106,500
Premium	£2,260–£3,040 per m²	£95,000–£127,500

Planning and building regulations in Rhiwbina

In Wales, a two-storey side extension can be permitted development if it is at least 10.5 m from the boundary opposite the side wall, set back at least 1 m from the front of the house and does not increase the house's widest width by more than 50%. If it fails any test, or the house is in a protected area, a householder application 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 Rhiwbina homes

Side windows, boundaries and gutters

Upstairs windows in the side wall face the neighbour, so they are usually obscure-glazed and fixed, or left out. Building close to the boundary also raises questions about foundations, overhanging gutters and access for maintenance, so we design the eaves and gutter to stay within your land.

Matching the ridge and roof

A hipped house usually needs a hipped extension roof, and a gabled house a gable. Matching the pitch, tiles, ridge detail and brick bond is what makes a side extension look original rather than added, and councils look closely at it on a front-facing addition.

How we'd run your project

Measure and listen
A visit to Rhiwbina to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Get it approved
Once you're happy with the design we submit it to the council for Rhiwbina and deal with any questions from the planning officer.
Detail and price
Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.
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 side extensions in Rhiwbina

Do I need planning permission for a two-storey side extension in Rhiwbina?

Rhiwbina is in Wales, so Wales planning rules apply. Can be permitted development in Wales if it is 10.5 m from the side boundary, set back 1 m from the front and doesn't widen the house by more than half; otherwise planning permission. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.

Which postcodes do you cover around Rhiwbina?

We cover Rhiwbina (CF14 and CF15) and nearby places including Whitchurch (Cardiff and the Vale of Glamorgan), Thornhill and Llandaff, plus the rest of Cardiff and the Vale of Glamorgan. The first site visit is free.

How much does a two-storey side extension cost in Rhiwbina?

Our guide for Wales, which covers Rhiwbina, is £1,890–£2,530 per m² including VAT. A typical project with a 3 m × 7 m footprint on two floors (42 m² of new floor space) comes to about £79,000–£106,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Who handles building regulations for a project in Rhiwbina?

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 I build a two-storey side extension over my driveway?

Yes, if the drive is wide enough for a useful room and the council accepts the design. You may lose off-road parking, which some councils weigh up, and the foundations need to suit the ground below. We check parking, drains and meter positions at the free site visit before any drawings are prepared.

Nearby

Other towns near Rhiwbina:

Other extensions in Rhiwbina

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

The quickest next step is a visit. We'll look at your house in Rhiwbina and give you an honest view of the options.