Glass box extensions in Dyfed
A glass extension in Dyfed starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide priceFrom £27,500 inc VAT
- PlanningWelsh permitted development rules (rear up to 4 m)
- Towns covered6
- Site visitFree, no obligation

Will the council need to approve it?
In Wales a glazed or orangery-style extension follows the normal single-storey limits (up to 4 m at the rear). Welsh building regulations also limit glazing and heat loss, so glass-heavy designs need calculations.
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.
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 should I budget for a glass extension in Dyfed?
These guide figures apply our Wales adjustment (×0.93) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Dyfed: £2,790 to £5,390 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2 m × 4 m 8 m² | £27,500 – £33,500 | £27,500 – £35,500 | £31,500 – £43,500 |
| 3 m × 4 m 12 m² | £33,000 – £40,500 | £39,000 – £49,500 | £47,500 – £65,000 |
| 3 m × 6 m 18 m² | £50,000 – £60,500 | £58,500 – £74,000 | £71,500 – £97,500 |
For a figure based on your own dimensions, use our guide-price tool.
When a glass extension makes sense
- Period and listed-style houses where a light touch is wanted
- Garden-facing dining rooms
- Small infill spaces and side returns
Working in Dyfed
Towns we cover in Dyfed include Llanelli, Ammanford, Aberystwyth, Carmarthen, Haverfordwest, Pembroke Dock. In Wales, terraced houses with rear offshoots are common in the towns, while detached houses and bungalows dominate in rural areas.
How the project works
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
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Glass extension questions answered
Will my neighbours in Dyfed be involved?
If a planning application is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Who do I contract with for a glass extension in Dyfed?
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 Dyfed?
Yes, across the whole of Dyfed. Site visits are free and there is no obligation.
Are glass extensions cold in winter?
Modern double or triple glazing with warm-edge spacers and underfloor heating keeps them comfortable. They are not as warm as a solid room, and we explain the trade-off honestly.
How much does a glass extension cost?
Our guide range is about £2,790 to £5,390 per m² including VAT, because structural glass is made to order. A 12 m² standard-spec glass extension is typically £39,000 to £49,500 in Dyfed.
Book a free site visit in Dyfed
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.