Abergavenny, Newport and Monmouthshire
Semi-detached rear extension in Abergavenny
For homes in Abergavenny, a semi-detached rear extension is often the simplest way to gain space without moving. Single or two-storey extensions for semi-detached houses, with side access and one party wall. We take it from survey to completion certificate.
Abergavenny is covered from our Newport and Monmouthshire round, including NP7. Semi-detached houses are common across Newport and Monmouthshire, and their side access makes rear extensions quicker to build.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a semi-detached rear extension cost in Abergavenny?
A semi-detached rear extension in Abergavenny is priced at £1,770–£2,880 per square metre including VAT as a guide, before kitchen fit-out and fees. Prices in Wales sit below our West Midlands baseline; sloping sites are the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £21,000–£34,500 |
| 4 m wide × 5 m deep (20 m²) | £35,500–£57,500 |
| 4 m wide × 6 m deep (24 m²) | £42,500–£69,000 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a semi-detached rear extension in Abergavenny?
Whether your semi-detached rear extension in Abergavenny needs a planning application depends on its size, your house and any local restrictions.
The Welsh Government's householder rules let many homes add a single-storey rear extension up to 4 metres deep and 4 metres high without a planning application. Deeper projects go through a householder application, because Wales has no prior approval route.
Welsh rules allow a two-storey rear extension without an application only where the ground floor is no deeper than 4 metres, the upper floor no deeper than 3 metres and at least 10.5 metres remains to the rear boundary. Most homeowners still apply for householder planning permission.
Conservation areas, National Parks and National Landscapes restrict permitted development in Wales, and listed buildings need listed building consent. At the first visit we measure what is there now and tell you which route fits: permitted development or a householder planning application.
What are homes in Abergavenny like to extend?
Abergavenny has Victorian terraces near the centre and semis further out. Welsh permitted development allows up to 4 metres at the rear for many houses.
How a semi-detached rear extension in Abergavenny comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Approvals
Permitted development check or householder planning application, then Building Regulations drawings to the Welsh Approved Documents and structural calculations, plus party wall notices where they apply.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Semi-detached rear extensions near Abergavenny
From Abergavenny, the nearest places we also cover are Brynmawr (7.2 miles) and Abertillery (8.0 miles).
- Semi-detached rear extension in Brynmawr
- Semi-detached rear extension in Abertillery
- Semi-detached rear extension in Pontypool
- Semi-detached rear extension in Ebbw Vale
- Semi-detached rear extension in Tredegar
Other work in Abergavenny:
FAQ
Semi-detached rear extension questions in Abergavenny
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
Can I match pebbledash or render?
Yes. Many semis are refinished with new render across the whole back elevation so old and new match.
Can you match the brick or stone on my Abergavenny house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
How much does a semi-detached rear extension cost in Abergavenny?
As a guide, £1,770–£2,880 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £21,000–£34,500 at that rate. Your written price follows the survey.
Is the site visit in Abergavenny free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.