Chelsfield, Kent
Glazed rear extension in Chelsfield
Full-height glass, slim frames and big rooflights for the most open rear room. We design, get the approvals for and build glazed and glass-box rear extensions in Chelsfield and the surrounding area, with one contract from the first survey to building control sign-off.
Chelsfield sits in Kent, with postcode districts including BR5 and BR6. If your garden in Chelsfield faces south, expect us to talk about overhangs and solar-control glass before frame colours.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a glazed rear extension cost in Chelsfield?
For Chelsfield we work from the South East England rate: £3,140–£5,380 per square metre of new floor, including VAT, standard specification. South East prices run above our West Midlands baseline, mainly on labour rates and clay-soil foundations.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £37,500–£64,500 |
| 4 m wide × 6 m deep (24 m²) | £75,500–£129,000 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a glazed rear extension in Chelsfield?
Whether your glazed rear extension in Chelsfield needs a planning application depends on its size, your house and any local restrictions.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.
New fabric must meet Approved Document L (2021 edition incorporating 2023 amendments): walls 0.18, roof 0.15 and floor 0.18 W/m²K, windows 1.4 W/m²K or Band B. Under the simple route, new windows, doors and rooflights should not exceed 25% of the extension floor area plus any openings removed; more glass is possible with a whole-house calculation.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.
What are homes in Chelsfield like to extend?
Commuter semis and detached houses make up much of Chelsfield, and longer gardens make England's prior approval route for deeper rear extensions worth considering.
How a glazed rear extension in Chelsfield comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Glazed rear extensions near Chelsfield
We also build glazed and glass-box rear extensions in nearby Orpington (1.7 miles) and Swanley (3.3 miles).
- Glazed rear extension in Orpington
- Glazed rear extension in Swanley
- Glazed rear extension in Bickley
- Glazed rear extension in Chislehurst
- Glazed rear extension in Sidcup
Other work in Chelsfield:
FAQ
Glazed rear extension questions in Chelsfield
Do you handle building control in Chelsfield?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Can I have a level threshold?
Yes, with a drainage channel outside the doors and the slab set to the patio level.
What postcode areas do you cover around Chelsfield?
Including BR5 and BR6, and the surrounding Kent area.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.