England
Rear extensions in Dorset
Across Dorset we handle the whole rear extension: survey, drawings, the planning route, building control and the build. Towns we cover here include Bournemouth, Poole and Weymouth.
What are homes in Dorset like to extend?
Dorset has Victorian terraces nearer the centre and post-war semis on the edges. Sloping gardens are frequent, which affects floor levels and steps down to the patio.
Rear extension prices in Dorset
South West prices run slightly above our West Midlands baseline; natural stone to match the house is the main variable. Per square metre including VAT, standard specification:
| Extension | Per m² |
|---|---|
| Single-storey rear extension | £1,980–£3,220 |
| Two-storey (per m² across both floors) | £1,870–£2,810 |
| Side return | £2,390–£3,950 |
| Wraparound | £2,290–£3,740 |
| Glass-led | £2,910–£4,990 |
Planning and building rules in Dorset
Under England's householder permitted development rules you can usually add 3 metres at the back of an attached house, or 4 metres on a detached house, without a planning application, as long as the extension stays under 4 metres high and its eaves stay under 3 metres where it 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.
The Party Wall etc. Act 1996 applies in England: you serve notice two months before work to a shared wall, and one month before digging foundations within 3 metres (or 6 metres for deeper foundations) of a neighbour's building. Neighbours can agree in writing; if they dissent, surveyors agree an award.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent.
Rear extensions we build in Dorset
- 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 detached houses
- Rear extensions for bungalows
- 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)
- Rear extension plans and planning applications
- Building Regulations for rear extensions
- Single-storey rear extensions
- Two-storey rear extensions
Towns and districts in Dorset
The main places we cover in Dorset include Bournemouth, Poole and Weymouth, across postcode areas BH and DT.
| Town | Postcode districts | Nearest town we also cover |
|---|---|---|
| Bournemouth | BH1, BH2, BH3 | Christchurch (4.4 miles) |
| Poole | BH12, BH13, BH14 | Canford Heath (2.6 miles) |
| Weymouth | DT3, DT4 | Portland (3.3 miles) |
| Christchurch | BH5, BH6, BH7 | Bournemouth (4.4 miles) |
| Ferndown | BH22 | Wimborne Minster (4.0 miles) |
| Dorchester | DT1 | Weymouth (7.2 miles) |
| Wimborne Minster | BH17, BH18 | Broadstone (1.9 miles) |
| Canford Heath | BH12, BH17, BH18 | Broadstone (1.2 miles) |
| Verwood | BH31 | Ringwood (4.1 miles) |
| Portland | DT5 | Weymouth (3.3 miles) |
- Bournemouth
- Poole
- Weymouth
- Christchurch
- Ferndown
- Dorchester
- Wimborne Minster
- Canford Heath
- Verwood
- Portland
- Bridport
- Blandford Forum
- Swanage
- Broadstone
Areas near Dorset
FAQ
Questions people ask
How much does a rear extension cost in Dorset?
As a guide, £1,980–£3,220 per square metre including VAT for a standard single-storey extension at South West England rates.
Do I need planning permission in Dorset?
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.
Which towns in Dorset do you cover?
14 towns and districts, including Bournemouth, Poole and Weymouth.
Do you handle building control?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.