Kent
Rear extensions in Chelsfield
Rear extensions in Chelsfield: single-storey and two-storey extensions, side returns, wraparounds and glass-led designs, planned around inter-war semis and 1960s estates and the English rules.
Chelsfield is in Kent, with postcode districts including BR5 and BR6. The nearest places we also cover are Orpington (1.7 miles) and Swanley (3.3 miles).
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Rear extensions we build in Chelsfield
- Single-storey rear extensions
- Two-storey rear extensions
- Kitchen-diner rear extensions
- Side return extensions
- Wraparound extensions
- Glazed and glass-box rear extensions
- Rear extensions for terraced houses
- Rear extensions for semi-detached houses
- Rear extensions for bungalows
- Rear extension plans and planning applications
Also available across Kent:
- Rear extensions for detached houses
- Flat-roof rear extensions
- Pitched and lean-to roof rear extensions
- Knocking through to a rear extension
- Roof lanterns and rooflights for rear extensions
- Permitted development rear extensions
- Larger home extension prior approval (England)
- Building Regulations for rear extensions
Rear extension prices in Chelsfield
South East prices run above our West Midlands baseline, mainly on labour rates and clay-soil foundations.
| Example | Guide inc VAT |
|---|---|
| Single-storey, 3 m × 4 m (12 m²) | £25,500–£41,500 |
| Single-storey, 4 m × 6 m (24 m²) | £51,000–£83,500 |
| Two-storey, 3 m × 5 m footprint (30 m²) | £60,500–£90,500 |
| Side return, about 14 m² | £36,000–£59,500 |
| Wraparound, about 25 m² | £61,500–£101,000 |
What are homes in Chelsfield like to extend?
Around Chelsfield the housing ranges from inter-war semis to 1960s and 1970s estates with good-sized gardens. Many of the newer estates had permitted development rights removed by condition, so we check the planning history before anything is drawn.
Planning rules for Chelsfield
In England a single-storey rear extension can often be built under permitted development: up to 3 metres beyond the original rear wall of an attached house, or 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres if any part is within 2 metres of a boundary.
England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.
Every rear extension in England needs Building Regulations approval, whether or not planning is needed. You can use the council's building control service or a registered building control approver, by full plans (checked before work, usually within five weeks) or a building notice, and you get a completion certificate at the end.
Nearby towns
FAQ
Questions people ask
How much is a rear extension in Chelsfield?
A 3 m × 4 m single-storey rear extension is about £25,500–£41,500 including VAT at our South East England guide rates; the written price follows a survey.
Do I need planning permission in Chelsfield?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.
Is the site visit in Chelsfield free?
Yes, with no obligation.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.