Glass box extensions across Blackwood
From the first sketch to final sign-off, we plan and build glass extensions in Blackwood and the surrounding Mid Glamorgan area.
- Guide price in BlackwoodFrom £27,500 inc VAT
- PlanningWelsh permitted development rules (rear up to 4 m)
- Build time10–16 weeks on site
- Postcode districtsCF82, NP12
What should I budget for a glass extension in Blackwood?
Prices below are for Blackwood, using the Wales factor of ×0.93. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Blackwood: £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 and approvals in Blackwood
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.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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).
Working in Blackwood
We cover Blackwood and the postcode districts CF82, NP12. We also work in nearby Gelligaer (2 miles), Risca (6 miles), Caerphilly (6 miles), Pontypridd (7 miles).
Pontypool, in Gwent, is roughly 7 miles from Blackwood and also on our list. 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.
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
Solar gain is the risk. We specify solar-control glass, plan for opening vents or sliding panels, and avoid fully glazed roofs on south-facing extensions unless shading is included.
Our process, step by step
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
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
The build is managed from start to finish, inspected at each stage and signed off on completion.
Glass extension questions answered
How long does a glass extension take to build in Blackwood?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Blackwood, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Who do I contract with for a glass extension in Blackwood?
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.
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 Blackwood.
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.
Book a free site visit in Blackwood
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.