Two-storey extensions for semi-detached houses in Abertillery
Thinking about a two-storey extension for a semi-detached house in Abertillery? We design it, take it through the approvals it needs and build it, with one team responsible from the first visit to the final certificate.
Abertillery: the key facts for this kind of project.
- Postcode districts
- NP13
- County / area
- Gwent, Wales
- Price region
- Wales
- Guide price
- £51,500–£69,500 (£1,840–£2,480 per m²)
- Approval route
- Depends on position: rear (3 m first floor, 10.5 m to the boundary) and some side extensions (10.5 m, 1 m set-back) can be permitted development in Wales.
- Nearest towns
- Crumlin (Gwent) (3.6 miles), Blaenavon (3.7 miles), Pontypool (4.3 miles)
- Distance to Newport (Gwent)
- about 11.4 miles
- First visit
- Free, no obligation
About a two-storey extension for a semi-detached house
A two-storey extension for a semi-detached house is a two-floor addition to the rear, the open side, or both, designed around the attached neighbour on one side. The rear is often the simplest option and can sometimes be permitted development, while a side extension uses the gap on the detached side. Both need care with the shared party wall and the neighbour's light.
We cover Abertillery (NP13) and the places around it, including Crumlin (Gwent) (3.6 miles), Blaenavon (3.7 miles) and Pontypool.
What it costs in Abertillery
Most of the cost of a two-storey extension for a semi-detached house is set by its size and specification. For Abertillery and the rest of Wales, our guide is £1,840–£2,480 per m² including VAT, so about £51,500–£69,500 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). 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 | A 4 m × 3.5 m footprint on two floors (28 m² of new floor space) |
|---|---|---|
| Essential | £1,690–£2,290 per m² | £47,500–£64,000 |
| Standard | £1,840–£2,480 per m² | £51,500–£69,500 |
| Premium | £2,210–£2,980 per m² | £62,000–£83,500 |
Planning and building regulations in Abertillery
In Wales, a semi can take a two-storey rear extension under permitted development with the ground floor up to 4 m and the first floor up to 3 m beyond the original rear wall, 10.5 m from the rear boundary. A side extension can also be permitted development if it is 10.5 m from the side boundary, set back 1 m and adds no more than 50% width. Otherwise the fee is £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 Abertillery homes
Keeping the pair balanced
Semis are designed as matching pairs, and a side extension changes that balance. Setting the side extension back from the front wall and keeping its ridge lower helps the pair still read as a pair, which councils' design guides commonly ask for.
The attached neighbour's light
A two-storey rear extension next to the party wall can take light from the neighbour's rear windows. Councils often use a 45-degree test, so the first floor may need to be shorter than the ground floor or set in from the shared boundary.
How we'd run your project
Free site visit
We visit your home in Abertillery, 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.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
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 extensions for semi-detached houses in Abertillery
How long does a two-storey extension for a semi-detached house 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.
How much does a two-storey extension for a semi-detached house cost in Abertillery?
Our guide for Wales, which covers Abertillery, is £1,840–£2,480 per m² including VAT. A typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) comes to about £51,500–£69,500. 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 Abertillery?
We cover Abertillery (NP13) and nearby places including Crumlin (Gwent), Blaenavon and Pontypool, plus the rest of Gwent. The first site visit is free.
What if my neighbour has already extended?
That often helps. An existing extension next door can reduce the effect of yours on their light, and may show what the council accepts on your street. It can also mean building alongside their wall, so we check its position, foundations and any windows facing your plot at the survey.
Will a side extension make my semi look like a terrace?
It can if it fills the whole gap to the boundary at first floor and the neighbour does the same. Many councils ask for a first-floor gap to the side boundary or a set-back for this reason. We design the extension to keep the semi reading as one of a pair.
Nearby
Nearby towns we cover for two-storey extensions for semi-detached houses:
Other extensions in Abertillery
- Rear
- Side
- Wraparound
- Part two-storey
- Over a garage
- First floor
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Abertillery · Two-storey extensions for semi-detached houses across Gwent
Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.