Part single, part two-storey extensions in Aberdare
Adding a part single, part two-storey extension in Aberdare 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.
Before you start in Aberdare, here's what applies.
- Postcode districts
- CF44
- County / area
- Mid 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
- Hirwaun (3.1 miles), Abercanaid (3.6 miles), Mountain Ash (3.6 miles)
- Distance to Rhondda
- about 3.8 miles
- First visit
- Free, no obligation
About a part single, part two-storey extension
A part single, part two-storey extension is an extension where the ground floor is wider or deeper than the floor above, so only part of it rises to two storeys. It usually gives a large kitchen or living area with roof lights below and one bedroom or bathroom above. It is often a good way to add space while limiting the effect on neighbours.
We cover Aberdare (CF44) and the places around it, including Hirwaun (3.1 miles), Abercanaid (3.6 miles) and Mountain Ash.
What it costs in Aberdare
A guide price for Aberdare: 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). That works out at £1,840–£2,530 per m² of new floor space, including VAT at 20%. These are guides, not quotes. Ground conditions, steelwork and access can move the figure either way.
| 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 Aberdare
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 Aberdare 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.
Where to put the two-storey part
The two-storey section usually works best away from the closest neighbour, with the single-storey part on that boundary side. We test a few positions against neighbours' windows, the upstairs layout and the roof shape before choosing the one to take forward.
How we'd run your project
Free site visit
We visit your home in Aberdare, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in Wales before drawing in detail.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
Finish and certify
Second fix, plastering and making good, then building control's final inspection and the completion paperwork.
Questions about part single, part two-storey extensions in Aberdare
How much does a part single, part two-storey extension cost in Aberdare?
Our guide for Wales, which covers Aberdare, 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.
Which postcodes do you cover around Aberdare?
We cover Aberdare (CF44) and nearby places including Hirwaun, Abercanaid and Mountain Ash, plus the rest of Mid Glamorgan. The first site visit is free.
Who handles building regulations for a project in Aberdare?
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.
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.
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.
Nearby
Other towns near Aberdare:
Other extensions in Aberdare
- Rear
- Side
- Wraparound
- Over a garage
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Aberdare · Part single, part two-storey extensions across Mid Glamorgan
Want a figure first? Try our guide price tool, then book a free visit to firm it up.