Essex
Two-storey rear extensions in Essex
A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. We design and build rear extensions across Essex, from Southend-on-Sea and Basildon to Colchester, covering single-storey kitchen extensions, two-storey additions, side returns and wraparounds.

In Essex we check the neighbours' rear windows first, because the upper floor is where most two-storey schemes win or lose planning. Post-war semis and newer estates are typical of Essex, and many have room for a full-width extension. Shrinkable clay is common in the East of England, so foundations near trees and hedges are designed to NHBC-style depth guidance.
How much does a two-storey rear extension cost in Essex?
In Essex, our guide for a two-storey rear extension is £1,910–£2,860 per square metre including VAT for a standard specification. East of England prices run slightly above our West Midlands baseline; clay soils near trees are the main foundation variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m × 5 m footprint, two floors (30 m²) | £57,000–£86,000 |
| 4 m × 6 m footprint, two floors (48 m²) | £91,500–£137,500 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission in Essex?
A two-storey rear extension can be permitted development in England only if it projects no more than 3 metres, stays at least 7 metres from the rear boundary, matches the existing roof pitch and has obscure-glazed upper side windows. In practice most double-storey rear extensions go through a householder planning application.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent.
Where in Essex do we work?
- Southend-on-Sea
- Basildon
- Colchester
- Chelmsford
- Harlow
- Grays
- Braintree
- Brentwood
- Clacton-on-Sea
- South Benfleet
- Canvey Island
- Billericay
- Rayleigh
- Stanford-le-Hope
- Wickford
- Witham
- Pitsea
- Maldon
- Waltham Abbey
- South Ockendon
- Harwich
- Hadleigh
- Walton-on-the-Naze
- Frinton-on-Sea
- Rochford
- Saffron Walden
- Tilbury
- Chafford Hundred
- Chigwell
- Halstead
- Buckhurst Hill
- Epping
FAQ
Questions people ask
Does a two-storey rear extension need planning permission?
Almost always. England and Northern Ireland allow 3 metres without an application only if at least 7 metres remains to the rear boundary; Wales and Scotland are similar or stricter.
Is two-storey cheaper per square metre than single-storey?
Usually yes, because the foundations and roof are shared across twice the floor area. The total cost is higher.
Can I add an en-suite upstairs?
Yes. We plan the soil pipe route early so the bathroom sits where drainage works without boxing through the room below.
Do you cover all of Essex?
We cover 32 towns and districts in Essex, including Southend-on-Sea, Basildon and Colchester.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.