Monmouth, Newport and Monmouthshire
Single-storey rear extension in Monmouth
Single-storey rear extension in Monmouth: ground-floor space across the back of the house, usually for a kitchen, dining or family room. We measure the house, show you what the rules allow, price it in writing and build it.
Monmouth sits in Newport and Monmouthshire, with postcode districts including NP25. A depth of 3 to 4 metres keeps many single-storey rear extensions in Monmouth within permitted development, subject to the house's planning history.
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 single-storey rear extension cost in Monmouth?
For Monmouth we work from the Wales rate: £1,770–£2,880 per square metre of new floor, including VAT, standard specification. 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 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission for a single-storey rear extension in Monmouth?
Planning for a single-storey rear extension in Monmouth follows the Welsh householder rules.
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.
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 Monmouth like to extend?
Older terraces near the centre and post-war semis further out are typical of Monmouth. Sloping sites are common in Wales, so floor levels and retaining walls are designed at the start.
How a single-storey rear extension in Monmouth comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Paperwork handled
Planning or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Single-storey rear extensions near Monmouth
We also build single-storey rear extensions in nearby Cinderford (9.2 miles) and Ross on Wye (9.5 miles).
- Single-storey rear extension in Cinderford
- Single-storey rear extension in Ross on Wye
- Single-storey rear extension in Chepstow
- Single-storey rear extension in Abergavenny
- Single-storey rear extension in Caldicot
Other work in Monmouth:
FAQ
Single-storey rear extension questions in Monmouth
How much does a single-storey rear extension cost in Monmouth?
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.
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.
Is a flat roof or a pitched roof better?
A warm flat roof keeps the extension low under first-floor windows and suits a roof lantern; a pitched or lean-to roof gives a vaulted ceiling. Both last for decades when built properly.
What postcode areas do you cover around Monmouth?
Including NP25, and the surrounding Newport and Monmouthshire area.
Do I need a party wall agreement?
In Wales, usually yes if the extension is on or near a shared boundary or close to a neighbour's foundations. We serve the notices.
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.