Glass box extensions in Farnworth: design, approvals and build
From the first sketch to final sign-off, we plan and build glass extensions in Farnworth and the surrounding Greater Manchester area.
- Guide price in FarnworthFrom £28,500 inc VAT
- PlanningSame limits as single-storey rear; glazing checked for building regs
- Build time10–16 weeks on site
- Postcode districtsBL3, BL4, M38
Included in a typical project
- Steel or glass beams and slim-frame glazing
- Design with specialist glazing input
- Drainage details for frameless roofs
- Planning drawings that show the glass detail
- Solar-control and low-energy glass specification
- 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.
How much does a glass extension cost in Farnworth?
These guide figures apply our North West England adjustment (×0.95) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Farnworth: £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 |
Want a range for your exact size? The guide-price tool takes about a minute.
Extensions in and around Farnworth
Across BL3, BL4, M38, we can visit, measure and advise. Nearby, we also take on projects in Walkden (2 miles), Bolton (3 miles), Radcliffe (3 miles), Tyldesley (4 miles).
For homes towards Merseyside, Golborne is around 10 miles away. Across the North West, terraced houses with small rear yards suit compact rear and side return extensions, while suburban semis have room for more.
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.
In a conservation area, national park, National Landscape, the Broads or a 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.
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.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
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
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Common questions in Farnworth
Who do I contract with for a glass extension in Farnworth?
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 Farnworth?
Yes. We cover Farnworth and the surrounding parts of Greater Manchester. Site visits are free and there is no obligation.
Do I need building regulations approval in Farnworth?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
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 Farnworth.
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 Farnworth
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.