Extensions over a garage in Monmouth
We plan and build extensions over a garage for homeowners in Monmouth and nearby. Every project starts with a free visit and a design stage priced in writing before any work begins.
The basics for Monmouth at a glance.
- Postcode districts
- NP25
- County / area
- Gwent, Wales
- Price region
- Wales
- Guide price
- £29,000–£42,000 (£1,610–£2,350 per m²)
- Approval route
- Can be permitted development in Wales if it is 10.5 m from the side boundary, set back 1 m from the front and doesn't widen the house by more than half; otherwise planning permission.
- Nearest towns
- Chepstow (12 miles), Abergavenny (13 miles), Caldicot (15.7 miles)
- Distance to Newport (Gwent)
- about 19.8 miles
- First visit
- Free, no obligation
About an extension over a garage
An extension over a garage is a new first-floor room built on top of an existing attached garage, usually a bedroom, en-suite or study. It uses a footprint you already have, so it adds floor space without taking any garden. The garage walls and foundations often need strengthening or replacing to carry the new floor.
We cover postcode district NP25 in and around Monmouth, along with neighbouring Chepstow, Abergavenny and Caldicot.
What it costs in Monmouth
Our guide for Wales is £1,610–£2,350 per m² including VAT. On a project with 3 m × 6 m of new first-floor space (18 m²), that puts an extension over a garage in Monmouth at roughly £29,000–£42,000. Design fees, structural calculations and approval fees are separate and listed on our prices page.
| Spec | Per m² | 3 m × 6 m of new first-floor space (18 m²) |
|---|---|---|
| Essential | £1,480–£2,160 per m² | £26,500–£39,000 |
| Standard | £1,610–£2,350 per m² | £29,000–£42,000 |
| Premium | £1,930–£2,820 per m² | £35,000–£50,500 |
Planning and building regulations in Monmouth
In Wales, building over a side garage can be permitted development if the result is at least 10.5 m from the boundary opposite the side wall, set back at least 1 m from the front of the house and does not widen the house by more than 50%. Garages close to the boundary usually fail these tests, so a householder application costing £585 is often needed.
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 Monmouth homes
Checking the garage foundations
Garages are often built on shallow strip footings sized for a single-storey wall and a light roof. A trial hole shows their depth and condition, and the engineer decides whether they can carry two storeys or need underpinning or new foundations inside the garage.
Floor levels and headroom
Garage floors are often lower than the house, and the new first floor may not line up with the existing landing. We set the floor level to avoid awkward steps upstairs, while keeping enough headroom in the garage below for a car or storage.
How we'd run your project
Understand the brief
At your home in Monmouth we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.
Design and approvals
We draw the extension and check it against the rules for Wales, then apply for planning permission or a certificate of lawfulness, whichever fits.
Engineer it
Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.
Build and hand over
We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.
Questions about extensions over a garage in Monmouth
Who handles building regulations for a project in Monmouth?
We handle it as part of the project. What's needed in Wales: building regulations approval under the Welsh Approved Documents, which differ from England's in places (notably energy efficiency). We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
Which postcodes do you cover around Monmouth?
We cover Monmouth (NP25) and nearby places including Chepstow, Abergavenny and Caldicot, plus the rest of Gwent. The first site visit is free.
How long does an extension over a garage 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 do I get into a room over the garage?
Usually through a new opening off the existing landing or a bedroom, so the stairs stay where they are. If the floor levels do not match, a step or two may be needed inside the new room. Where a landing opening is not practical, a new stair from a converted garage is an option.
Can I add an en-suite above the garage?
Yes, and it is a common choice for a main bedroom. The en-suite needs an extract fan under Part F, a route for the soil pipe down to the drains and enough fall for the waste, which can be harder over a garage. We plan the pipe route through the garage or an outside wall early.
Nearby
Other towns near Monmouth:
Other extensions in Monmouth
- Rear
- Side
- Wraparound
- Part two-storey
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Monmouth · Extensions over a garage across Gwent
Tell us about your house in Monmouth and we'll call you back to arrange a free, no-obligation visit.