Side extensions across Monmouth
Planning a side extension in Monmouth? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide price in MonmouthFrom £20,000 inc VAT
- PlanningSingle storey can be permitted development
- Build time10–18 weeks on site
- Postcode districtsNP25
Planning rules that apply in Monmouth
In Wales a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house, and it must not come closer to a highway than the existing side wall. Larger side extensions need planning permission.
Homes in conservation areas, national parks, National Landscapes (AONBs) and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building over or within 3 m of a public sewer needs the water company's consent before the foundations go in.
The Party Wall etc. Act 1996 applies in Wales as in England: notice must be served before work to a shared wall, building on the boundary, or excavating close to a neighbour's foundations.
Applications are decided by the local planning authority (your county or county borough council, or the national park authority).
Guide prices for Monmouth
Labour and material costs vary across the UK, so for Monmouth we use our Wales factor (×0.93). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Monmouth: £1,630 to £3,160 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £20,000 – £25,000 | £22,500 – £30,000 | £29,000 – £38,000 |
| 3 m × 6 m 18 m² | £29,000 – £35,500 | £34,000 – £44,500 | £43,500 – £57,000 |
| 3 m × 8 m 24 m² | £39,000 – £47,000 | £45,500 – £59,500 | £58,000 – £76,000 |
Want a range for your exact size? The guide-price tool takes about a minute.
Extensions in and around Monmouth
We cover Monmouth and the postcode districts NP25. The same team covers Chepstow (11 miles), Abergavenny (12 miles), Pontypool (15 miles), Cwmbran (16 miles), all within easy reach.
Just over the Mid Glamorgan border, Risca is about 21 miles away. Welsh housing ranges from stone terraces in the valleys to render-and-slate houses and modern estates, and the Welsh planning rules differ from England's in several places.
When a side extension makes sense
- Homes needing a utility, study or ground-floor bedroom
- Detached and semi-detached houses with side land
- Houses where the rear garden is small
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Common questions in Monmouth
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Monmouth, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of Monmouth?
Yes. We cover Monmouth and the surrounding parts of Gwent. Site visits are free and there is no obligation.
Who do I contract with for a side extension in Monmouth?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
How much does a side extension cost?
Our guide range is about £1,630 to £3,160 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £34,000 to £44,500 in Monmouth.
Can I build over my driveway?
Yes, if the foundations work and you keep any parking the council requires. Drains and services under drives are common, so we check before design.
Book a free site visit in Monmouth
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.