Seaford, East Sussex
Two-storey rear extension in Seaford
A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. If you live in Seaford and want to know what a two-storey rear extension would cost and whether it needs planning, start with the online guide price or a free site visit.
Seaford and its postcode districts BN25 are part of our East Sussex coverage. In East Sussex we check the neighbours' rear windows first, because the upper floor is where most two-storey schemes win or lose planning.
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 two-storey rear extension cost in Seaford?
Guide prices for a two-storey rear extension in Seaford start from our South East England rate of £2,020–£3,020 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 × 5 m footprint, two floors (30 m²) | £60,500–£90,500 |
| 4 m × 6 m footprint, two floors (48 m²) | £97,000–£145,000 |
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 two-storey rear extension in Seaford?
Here is how the rules in England apply to a two-storey rear extension in Seaford.
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.
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 Seaford like to extend?
Seaford 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 two-storey rear extension in Seaford comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
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.
Two-storey rear extensions near Seaford
Neighbouring places we cover include Newhaven (2.7 miles) and Peacehaven (5.0 miles).
- Two-storey rear extension in Newhaven
- Two-storey rear extension in Peacehaven
- Two-storey rear extension in Rottingdean
- Two-storey rear extension in Eastbourne
- Two-storey rear extension in Lewes
Other work in Seaford:
FAQ
Two-storey rear extension questions in Seaford
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.
Can you match the brick or stone on my Seaford house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
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.
How long does a rear extension take to build in Seaford?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Do I need planning permission for a rear extension in Seaford?
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.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.