Semi-detached rear extension in Southport

How much does a semi-detached rear extension cost in Southport?

For Southport we work from the North West England rate: £1,790–£2,910 per square metre of new floor, including VAT, standard specification. North West prices sit below our West Midlands baseline; access on terraced streets is the main variable.

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 Southport?

Planning for a semi-detached rear extension in Southport follows the English householder rules.

In England a single-storey rear extension can often be built under permitted development: up to 3 metres beyond the original rear wall of an attached house, or 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres if any part is 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 Southport like to extend?

Southport has long runs of terraced houses with back yards and alleys, plus 1930s semis further out. Yard extensions on terraces are often single-storey and close to both boundaries.

How a semi-detached rear extension in Southport comes together

1. Survey visit

   We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.

2. Drawings and budget

   Floor plans and elevations for the options, each with a guide price.

3. Paperwork handled

   Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.

4. 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 Southport

We also build rear extensions for semi-detached houses in nearby Formby (6.5 miles) and Lytham St Annes (6.7 miles).

• Semi-detached rear extension in Formby
• Semi-detached rear extension in Lytham St Annes
• Semi-detached rear extension in Ormskirk
• Semi-detached rear extension in Maghull
• Semi-detached rear extension in Skelmersdale

Other work in Southport:

• Single-storey rear extension
• Two-storey rear extension
• Kitchen-diner rear extension
• Side return extension
• Wraparound extension
• Glazed rear extension

All rear extensions in Southport