Southend-on-Sea, Essex
Semi-detached rear extension in Southend-on-Sea
We plan and build rear extensions for semi-detached houses for homeowners in Southend-on-Sea. Single or two-storey extensions for semi-detached houses, with side access and one party wall. Start with a free site visit, then a written price once the design is agreed.
We cover Southend-on-Sea (SS0, SS1, SS2 and SS3) as part of our Essex work. Semi-detached houses are common across Essex, and their side access makes rear extensions quicker to build.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a semi-detached rear extension cost in Southend-on-Sea?
A semi-detached rear extension in Southend-on-Sea is priced at £2,010–£3,290 per square metre including VAT as a guide, before kitchen fit-out and fees. 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 wide × 4 m deep (12 m²) | £24,000–£39,500 |
| 4 m wide × 5 m deep (20 m²) | £40,500–£65,500 |
| 4 m wide × 6 m deep (24 m²) | £48,500–£79,000 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a semi-detached rear extension in Southend-on-Sea?
Whether your semi-detached rear extension in Southend-on-Sea needs a planning application depends on its size, your house and any local restrictions.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.
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.
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.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Southend-on-Sea like to extend?
Southend-on-Sea mixes Victorian terraces with 1930s semis, so both side returns and full-width kitchen extensions suit houses here.
How a semi-detached rear extension in Southend-on-Sea comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Semi-detached rear extensions near Southend-on-Sea
From Southend-on-Sea, the nearest places we also cover are Rochford (3.1 miles) and Hadleigh (4.6 miles).
- Semi-detached rear extension in Rochford
- Semi-detached rear extension in Hadleigh
- Semi-detached rear extension in Rayleigh
- Semi-detached rear extension in Canvey Island
- Semi-detached rear extension in South Benfleet
Other work in Southend-on-Sea:
FAQ
Semi-detached rear extension questions in Southend-on-Sea
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
Is the site visit in Southend-on-Sea free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
Do I need a party wall agreement?
Usually with the attached neighbour, in England and Wales.
How long does a rear extension take to build in Southend-on-Sea?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
Do you handle building control in Southend-on-Sea?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.