Rottingdean, East Sussex
Semi-detached rear extension in Rottingdean
Thinking about a semi-detached rear extension in Rottingdean? Single or two-storey extensions for semi-detached houses, with side access and one party wall. Our team handles the drawings, the planning route and the build, and your contract is with one company throughout.
Rottingdean is covered from our East Sussex round, including BN1 and BN2. Where a Rottingdean 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 Rottingdean?
Guide prices for a semi-detached rear extension in Rottingdean 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 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a semi-detached rear extension in Rottingdean?
Whether your semi-detached rear extension in Rottingdean 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.
England's rules allow a rear extension of more than one storey without an application only when it is no deeper than 3 metres and at least 7 metres from the boundary opposite the rear wall, and never on designated land. Most two-storey schemes need householder planning permission.
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 Rottingdean like to extend?
Rottingdean 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. In Rottingdean we measure the attached neighbour's extension at the survey, because it often sets the sensible depth for yours.
How a semi-detached rear extension in Rottingdean comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Semi-detached rear extensions near Rottingdean
From Rottingdean, the nearest places we also cover are Peacehaven (2.6 miles) and Brighton (3.7 miles).
- Semi-detached rear extension in Peacehaven
- Semi-detached rear extension in Brighton
- Semi-detached rear extension in Hove
- Semi-detached rear extension in Newhaven
- Semi-detached rear extension in Lewes
Other work in Rottingdean:
FAQ
Semi-detached rear extension questions in Rottingdean
How much does a semi-detached rear extension cost in Rottingdean?
As a guide, £2,130–£3,470 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £25,500–£41,500 at that rate. Your written price follows the survey.
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.
Do I need a party wall agreement?
Usually with the attached neighbour, in England and Wales.
What postcode areas do you cover around Rottingdean?
Including BN1 and BN2, and the surrounding East Sussex area.
Do I need planning permission for a rear extension in Rottingdean?
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.
Is the site visit in Rottingdean free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.