Extensions in Monmouth: design, planning and build
More space without moving: we plan and build extensions across Monmouth, with one team for the drawings, the council and the build.
- Postcode districtsNP25
- Price regionWales (×0.93)
- Planning rulesWales
- Site visitFree, no obligation
Guide prices for Monmouth
We publish guide prices so you can budget before anyone visits. For Monmouth they are adjusted by ×0.93, the factor we use across Wales.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Wraparound extensions | 25 m² | £53,000 – £67,500 |
| Double-storey extensions | 32 m² | £53,500 – £70,000 |
| Orangery extensions | 16 m² | £41,500 – £52,500 |
| Side return extensions | 11 m² | £24,500 – £31,000 |
| Conservatory replacement extensions | 14 m² | £27,500 – £36,000 |
Covering Monmouth and nearby
We cover Monmouth and the postcode districts NP25. The same team covers Chepstow (11 miles), Abergavenny (12 miles), Pontypool (15 miles), Cwmbran (16 miles), Newport, Gwent (19 miles), all within easy reach. Just over the Mid Glamorgan border, Risca is about 21 miles away.
Approvals for an extension in Monmouth
In Wales a single-storey rear extension can usually project up to 4 m beyond the rear wall without a planning application, if it is no more than 4 m high, keeps eaves to 3 m and overall height to 4 m within 2 m of a boundary, and covers no more than half the land around the original house. Wales has no larger home extension prior approval scheme.
In Wales a single-storey side return can fall within permitted development if it stays within the 4 m height limit and the width rules for side extensions. Conservation areas and listed buildings need consent, and the Party Wall Act applies to work on or near a shared wall.
In a conservation area, national park, National Landscape or World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
Building regulations approval is separate from planning. Wales has its own building regulations and approved documents; the council or a registered building control approver checks the plans, inspects the work and issues a completion certificate.
Applications are decided by the local planning authority (your county or county borough council, or the national park authority).
What works best for Monmouth houses?
In Wales, terraced houses with rear offshoots are common in the towns, while detached houses and bungalows dominate in rural areas.
Depending on the plot, side return extensions and bungalow extensions are often the strongest options, with single-storey rear extensions worth considering where there is room.
Every extension type in Monmouth
- Pitched roof extensions · from £20,500
- Home office extensions · from £14,500
- Building regulations for extensions · from £800
- Extension plans and drawings · from £1,100
- Extensions over a garage · from £22,000
- Flat roof extensions · from £19,500
- Conservatory replacement extensions · from £18,500
- Annexe extensions · from £51,000
- Glass box extensions · from £27,500
- Utility and boot room extensions · from £13,000
- Bedroom extensions · from £24,000
- Porch extensions · from £3,700
- Planning permission for extensions · from £300
- Bungalow extensions · from £24,000
- Timber frame extensions · from £19,500
- Orangery extensions · from £27,500
- Side return extensions · from £16,500
- Wraparound extensions · from £33,000
- Single-storey rear extensions · from £19,500
- Double-storey extensions · from £35,000
- Kitchen extensions · from £25,000
- Side extensions · from £20,000
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
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Questions about extensions in Monmouth
How much does an extension cost in Monmouth?
Using our Wales factor (×0.93), a standard-spec single-storey extension of 20 m² is a guide £38,000 to £48,500 including VAT, and a 32 m² two-storey extension £53,500 to £70,000. Your written price follows the survey.
Who do I contract with?
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.
Do you cover all of Monmouth?
Yes, including the surrounding parts of Gwent. Site visits are free and there is no obligation.
Will my neighbours need to be told?
If you apply for planning the council notifies them, and in Wales party wall notices may be needed for work near a shared boundary.
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.