Two-storey extensions in Chelmsford
Need more room in Chelmsford? Two-storey and first-floor extensions add bedrooms and living space without moving. Here's everything we offer locally.
Chelmsford at a glance
- Postcode districts
- CM1 and CM2
- Area
- Essex, England
- Price region
- East of England
- Nearest towns
- Billericay (7.7 miles), Witham (8.6 miles), Maldon (8.8 miles), Wickford (8.9 miles)
- Distance to Southend-on-Sea
- about 17.2 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 postcode districts CM1 and CM2 in and around Chelmsford, along with neighbouring Billericay, Witham and Maldon.
Extensions available in Chelmsford
Two-storey rear extensions
Our East of England guide starts at £57,500 for this type.
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Two-storey side extensions
Our East of England guide starts at £88,500 for this type.
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Two-storey wraparound extensions
Our East of England guide starts at £124,000 for this type.
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Part single, part two-storey extensions
Guide from £74,000 in Chelmsford, including VAT.
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Extensions over a garage
From £32,500 in Chelmsford. Free visit to firm it up.
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First-floor extensions
Chelmsford guide price from £26,000, Standard spec.
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Two-storey extensions for semi-detached houses
Chelmsford guide price from £57,500, Standard spec.
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Two-storey extensions for detached houses
From £88,500 in Chelmsford. Free visit to firm it up.
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Kitchen extensions with bedrooms above
Chelmsford guide price from £57,500 (before kitchen units), Standard spec.
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Extra bedroom and en-suite extensions
Guide from £57,500 (plus en-suite) in Chelmsford, including VAT.
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 Chelmsford we also design annexes, home offices and bedrooms over garages.
Also available in Essex
- 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 Chelmsford
Chelmsford 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 Chelmsford
Do you cover Chelmsford?
Yes. We cover Chelmsford (CM1 and CM2) and the surrounding area, including Billericay and Witham. The first site visit is free.
What does a two-storey extension cost in Chelmsford?
Using our East of 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 Chelmsford do you cover?
Everywhere around it, including Billericay (7.7 miles), Witham (8.6 miles) and Maldon (8.8 miles), and the rest of Essex.