Extensions over a garage for homes in West Glamorgan
Thinking about an over-garage extension for your West Glamorgan home? Start with a free site visit: we measure up, check what the council will allow and give you honest guide figures on the day.
- Guide priceFrom £22,000 inc VAT
- PlanningAn application to the council is needed
- Towns covered5
- Site visitFree, no obligation

Towns in West Glamorgan
Local to West Glamorgan
Towns we cover in West Glamorgan include Swansea, Neath, Briton Ferry, Gorseinon, Clydach. In Wales, terraced houses with rear offshoots are common in the towns, while detached houses and bungalows dominate in rural areas.
When an over-garage extension makes sense
- Homes where the landing can connect to the new room
- Detached and link-detached houses with an attached garage
- Families needing a bedroom without losing garden
Fitting the new room to the existing landing is the planning puzzle inside the house. We design the connection first, then the roof, so the extension does not end up with awkward steps or a corridor through a bedroom.
How much does an over-garage extension cost in West Glamorgan?
For West Glamorgan we adjust our national guide rates by ×0.93, the factor we use for Wales. Figures include VAT; your written quote after the survey replaces them.
Typical rates in West Glamorgan: £1,670 to £3,160 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Over a single garage 12 m² | £22,000 – £27,500 | £23,000 – £30,500 | £30,000 – £38,000 |
| Over a large single garage 16 m² | £26,500 – £33,000 | £31,000 – £40,500 | £40,000 – £51,000 |
| Over a double garage 24 m² | £40,000 – £49,500 | £46,500 – £60,500 | £60,000 – £76,000 |
Want a range for your exact size? The guide-price tool takes about a minute.
Do I need planning permission in West Glamorgan?
In Wales a two-storey side extension must be at least 10.5 m from the side boundary to be permitted development, which few houses can meet, so a planning application to the council is the usual route for a room over a garage.
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 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.
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).
What happens next
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
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
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Over-garage extension questions answered
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for West Glamorgan, 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 West Glamorgan?
Yes, across the whole of West Glamorgan. Site visits are free and there is no obligation.
How long does an over-garage extension take to build in West Glamorgan?
On site, typically 12 to 18 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.
Can my garage take the weight of a room on top?
Some can and some cannot. Many garages have a single-skin wall or shallow foundations. Our structural engineer checks this before we give a fixed price.
How much does a room over a garage cost?
Our guide range is about £1,670 to £3,160 per m² including VAT. A single-garage room of about 12 m² usually costs £23,000 to £30,500 at standard spec, more if the garage needs rebuilding.
Book a free site visit in West Glamorgan
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.