Glass box extensions across Blackburn
If you live in Blackburn and want more space without moving, a glass extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.
- Guide price in BlackburnFrom £28,500 inc VAT
- PlanningSame limits as single-storey rear; glazing checked for building regs
- Build time10–16 weeks on site
- Postcode districtsBB1, BB2, BB3, BB5, BB6
Local to Blackburn
Site visits are available across Blackburn (BB1, BB2, BB3, BB5, BB6). We also work in nearby Darwen (4 miles), Accrington (5 miles), Chorley (9 miles), Rawtenstall (9 miles).
Horwich, in Greater Manchester, is roughly 11 miles from Blackburn and also on our list. The North West has a high share of Victorian and Edwardian terraces with rear yards and outriggers, plus large areas of inter-war semis in the suburbs.
How much does a glass extension cost in Blackburn?
Labour and material costs vary across the UK, so for Blackburn we use our North West England factor (×0.95). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Blackburn: £2,850 to £5,510 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2 m × 4 m 8 m² | £28,500 – £34,500 | £28,500 – £36,000 | £32,500 – £44,500 |
| 3 m × 4 m 12 m² | £34,000 – £41,500 | £39,500 – £50,500 | £49,000 – £66,500 |
| 3 m × 6 m 18 m² | £51,000 – £62,000 | £59,500 – £75,500 | £73,500 – £99,500 |
For a figure based on your own dimensions, use our guide-price tool.
Included in a typical project
- Solar-control and low-energy glass specification
- Steel or glass beams and slim-frame glazing
- Design with specialist glazing input
- Whole-house energy calculations where needed
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.
Will the council need to approve it?
In England a glazed or orangery-style extension follows the same size limits as any single-storey rear extension: 3 m or 4 m without an application, or up to 6 m and 8 m through prior approval. Building regulations limit glazing to about a quarter of the new floor area plus the openings it replaces, unless whole-house calculations show the design still performs.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads 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. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
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
We visit your Blackburn home, measure up, talk through what you want and check the planning position.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
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.
Questions people ask about glass extensions
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Blackburn, 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 I need building regulations approval in Blackburn?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Will my neighbours in Blackburn be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
How much does a glass extension cost?
Our guide range is about £2,850 to £5,510 per m² including VAT, because structural glass is made to order. A 12 m² standard-spec glass extension is typically £39,500 to £50,500 in Blackburn.
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 Blackburn
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.