Part single, part two-storey extensions in Whitchurch (Cardiff and the Vale of Glamorgan)
Adding a part single, part two-storey extension in Whitchurch (Cardiff and the Vale of Glamorgan) gives you two new rooms stacked on one footprint. Here's how we'd approach it, what it typically costs and the rules that apply in Wales.
Quick reference for homeowners in Whitchurch (Cardiff and the Vale of Glamorgan).
- Postcode districts
- CF14
- County / area
- Cardiff and the Vale of Glamorgan, Wales
- Price region
- Wales
- Guide price
- £66,000–£91,000 (£1,840–£2,530 per m²)
- Approval route
- It may be permitted development if the ground floor goes no more than 4 m and the first floor no more than 3 m beyond the original rear wall, with the first floor 10.5 m from the rear boundary.
- Nearest towns
- Rhiwbina (1.2 miles), Llandaff (1.3 miles), Thornhill (2.4 miles)
- Distance to Cardiff
- about 2.8 miles
- First visit
- Free, no obligation
About a part single, part two-storey extension
A part single, part two-storey extension suits you if you want a generous ground floor but only need one extra room upstairs, or if a full two-storey design would affect a neighbour too much. You get design options that test where the two-storey part works best, the approvals your nation needs, structural design, building regulations approval and the build, carried out by vetted teams working under S&K.
We cover postcode district CF14 in and around Whitchurch (Cardiff and the Vale of Glamorgan), along with neighbouring Rhiwbina, Llandaff and Thornhill.
What it costs in Whitchurch (Cardiff and the Vale of Glamorgan)
In Wales, which includes Whitchurch (Cardiff and the Vale of Glamorgan), we'd expect a part single, part two-storey extension to cost around £66,000–£91,000 for a 6 m × 4 m ground floor and a first floor over half of it (36 m² in total), or £1,840–£2,530 per m² including VAT. Professional fees for drawings and the structural engineer are listed separately on our prices page.
| Spec | Per m² | A 6 m × 4 m ground floor and a first floor over half of it (36 m² in total) |
|---|---|---|
| Essential | £1,690–£2,330 per m² | £61,000–£84,000 |
| Standard | £1,840–£2,530 per m² | £66,000–£91,000 |
| Premium | £2,210–£3,040 per m² | £79,500–£109,500 |
Planning and building regulations in Whitchurch (Cardiff and the Vale of Glamorgan)
In Wales, a part two-storey rear extension can be permitted development if the first floor goes no more than 3 m and the ground floor no more than 4 m beyond the original rear wall, with the first floor at least 10.5 m from the rear boundary. Conservation areas and other protected areas are excluded. If the design falls outside these limits, 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 Whitchurch (Cardiff and the Vale of Glamorgan) homes
Structure at the step
The first-floor wall above often sits over the new open-plan space, so it needs a steel beam or frame to carry it. Loads come down at different points than in a full two-storey design, and the engineer sizes the foundations to suit each part.
The roof junction
Where the single-storey roof meets the two-storey wall you need a sound weathering detail, usually a lead or similar flashing, and enough height for roof lights or a lantern. We set the roof falls and the upstairs window sill heights together so they do not clash.
How we'd run your project
Free site visit
We visit your home in Whitchurch (Cardiff and the Vale of Glamorgan), look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Drawings and permission
Our designers produce plans and elevations, then we take care of planning or permitted development checks with the council covering Whitchurch (Cardiff and the Vale of Glamorgan).
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 part single, part two-storey extensions in Whitchurch (Cardiff and the Vale of Glamorgan)
How much does a part single, part two-storey extension cost in Whitchurch (Cardiff and the Vale of Glamorgan)?
Our guide for Wales, which covers Whitchurch (Cardiff and the Vale of Glamorgan), is £1,840–£2,530 per m² including VAT. A typical project with a 6 m × 4 m ground floor and a first floor over half of it (36 m² in total) comes to about £66,000–£91,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
How long does a part single, part two-storey 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.
Which postcodes do you cover around Whitchurch (Cardiff and the Vale of Glamorgan)?
We cover Whitchurch (Cardiff and the Vale of Glamorgan) (CF14) and nearby places including Rhiwbina, Llandaff and Thornhill, plus the rest of Cardiff and the Vale of Glamorgan. The first site visit is free.
Can the single-storey part be deeper than the two-storey part?
With planning permission, yes, and that is often the point of the design: the ground floor projects further into the garden while the first floor stays back from neighbours. Under permitted development, the depth limits for extensions of more than one storey can apply to the whole extension, so we confirm which route applies before drawings are finalised.
Which side should the two-storey part go on?
Usually the side furthest from the nearest neighbour's windows, so the single-storey part sits nearest them and keeps their light. Other factors are where the stairs land upstairs, which room needs the extra space and where drains run. We sketch options at the design stage and explain which is most likely to be approved.
Nearby
Nearby towns we cover for part single, part two-storey extensions:
Other extensions in Whitchurch (Cardiff and the Vale of Glamorgan)
- Rear
- Side
- Wraparound
- Over a garage
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Whitchurch (Cardiff and the Vale of Glamorgan) · Part single, part two-storey extensions across Cardiff and the Vale of Glamorgan
Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.