Two-storey extensions in Dorchester
Need more room in Dorchester? Two-storey and first-floor extensions add bedrooms and living space without moving. Here's everything we offer locally.
Dorchester at a glance
- Postcode districts
- DT1 and DT2
- Area
- Dorset, England
- Price region
- South West England
- Nearest towns
- Weymouth (7.2 miles), Portland (10.3 miles), Bridport (14.3 miles), Blandford Forum (15.5 miles)
- Distance to Bournemouth
- about 24.2 miles
- Approvals
- Two-storey rear: up to 3 m deep and 7 m from the rear boundary under permitted development. Side, wraparound and front: planning permission.
We cover Dorchester (DT1 and DT2) and the places around it, including Weymouth (7.2 miles), Portland (10.3 miles) and Bridport.
Extensions available in Dorchester
Two-storey rear extensions
Guide from £57,500 in Dorchester, including VAT.
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Two-storey side extensions
Our South West England guide starts at £88,500 for this type.
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Two-storey wraparound extensions
Design, approvals and build for Dorchester homes. Guide from £124,000.
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Part single, part two-storey extensions
For homes in Dorchester: typical guide from £74,000.
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Extensions over a garage
Our South West England guide starts at £32,500 for this type.
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First-floor extensions
Our South West England guide starts at £26,000 for this type.
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Two-storey extensions for semi-detached houses
Dorchester guide price from £57,500, Standard spec.
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Two-storey extensions for detached houses
Design, approvals and build for Dorchester homes. Guide from £88,500.
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Kitchen extensions with bedrooms above
Dorchester guide price from £57,500 (before kitchen units), Standard spec.
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Extra bedroom and en-suite extensions
Design, approvals and build for Dorchester homes. Guide from £57,500 (plus en-suite).
Learn moreWhich type suits your house?
Start with what you need the space for. Bedrooms and an en-suite upstairs with a bigger kitchen below is the classic two-storey brief, but in Dorchester we also design annexes, home offices and bedrooms over garages.
Also available in Dorset
- Two-storey front extensions
- Two-storey extensions for end-of-terrace houses
- Two-storey annexe extensions
- Garage conversions with a room above
- Two-storey extension plans and drawings
- Planning permission for two-storey extensions
- Structural engineering for two-storey extensions
- Building regulations for two-storey extensions
- Party wall notices for extensions
- Design and build two-storey extensions
Rules for Dorchester
Dorchester is in England. Two-storey rear: up to 3 m deep and 7 m from the rear boundary under permitted development. Side, wraparound and front: planning permission. Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
The full England rules explained
Questions about extensions in Dorchester
Do you cover Dorchester?
Yes. We cover Dorchester (DT1 and DT2) and the surrounding area, including Weymouth and Portland. The first site visit is free.
What does a two-storey extension cost in Dorchester?
Using our South West England guide, a two-storey rear extension with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) is about £57,500–£78,000 including VAT. An extension over a garage is about £32,500–£47,500.
Which other places near Dorchester do you cover?
Everywhere around it, including Weymouth (7.2 miles), Portland (10.3 miles) and Bridport (14.3 miles), and the rest of Dorset.