Glass box extensions in Llanelli: design, approvals and build
From the first sketch to final sign-off, we plan and build glass extensions in Llanelli and the surrounding Dyfed area.
- Guide price in LlanelliFrom £27,500 inc VAT
- PlanningWelsh permitted development rules (rear up to 4 m)
- Build time10–16 weeks on site
- Postcode districtsSA15
Local to Llanelli
Our survey diary covers Llanelli, including SA15. The same team covers Ammanford (11 miles), Carmarthen (13 miles), Pembroke Dock (33 miles), Haverfordwest (36 miles), all within easy reach.
Just over the West Glamorgan border, Gorseinon is about 5 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.
Guide prices for Llanelli
For Llanelli 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 Llanelli: £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 |
Try the guide-price tool to see a range for your own size and finish.
Planning rules that apply in Llanelli
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.
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 over or within 3 m of a public sewer needs the water company's consent before the foundations go in.
Applications are decided by the local planning authority (your county or county borough council, or the national park authority).
Who a glass extension suits
- Garden-facing dining rooms
- Period and listed-style houses where a light touch is wanted
- Small infill spaces and side returns
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Common questions in Llanelli
Will my neighbours in Llanelli 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.
How long does a glass extension take to build in Llanelli?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.
Do I need building regulations approval in Llanelli?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
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 Llanelli.
Book a free site visit in Llanelli
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.