Shoreham-by-Sea, West Sussex
Semi-detached rear extension in Shoreham-by-Sea
Single or two-storey extensions for semi-detached houses, with side access and one party wall. We design, get the approvals for and build rear extensions for semi-detached houses in Shoreham-by-Sea and the surrounding area, with one contract from the first survey to building control sign-off.
Shoreham-by-Sea and its postcode districts BN42 and BN43 are part of our West Sussex coverage. Where a Shoreham-by-Sea semi already has a small lean-to at the back, we usually replace it rather than extend it.
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 Shoreham-by-Sea?
Guide prices for a semi-detached rear extension in Shoreham-by-Sea start from our South East England rate of £2,130–£3,470 per square metre, including VAT. South East prices run above our West Midlands baseline, mainly on labour rates and clay-soil foundations.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £25,500–£41,500 |
| 4 m wide × 5 m deep (20 m²) | £42,500–£69,500 |
| 4 m wide × 6 m deep (24 m²) | £51,000–£83,500 |
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 Shoreham-by-Sea?
Planning for a semi-detached rear extension in Shoreham-by-Sea follows the English householder rules.
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. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.
What are homes in Shoreham-by-Sea like to extend?
Shoreham-by-Sea has a mix of Victorian terraces near the centre and larger Edwardian and inter-war houses further out. Clay soils across much of the South East mean deeper foundations near trees, which we plan for at the survey.
How a semi-detached rear extension in Shoreham-by-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.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Semi-detached rear extensions near Shoreham-by-Sea
Close by, we work in Lancing, about 2.1 miles away, and Portslade, about 2.6 miles away.
- Semi-detached rear extension in Lancing
- Semi-detached rear extension in Portslade
- Semi-detached rear extension in Worthing
- Semi-detached rear extension in Hove
- Semi-detached rear extension in Brighton
Other work in Shoreham-by-Sea:
FAQ
Semi-detached rear extension questions in Shoreham-by-Sea
What postcode areas do you cover around Shoreham-by-Sea?
Including BN42 and BN43, and the surrounding West Sussex area.
Can you match the brick or stone on my Shoreham-by-Sea house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
Can I match pebbledash or render?
Yes. Many semis are refinished with new render across the whole back elevation so old and new match.
Do I need planning permission for a rear extension in Shoreham-by-Sea?
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.
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 I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.