Rear extension planning drawings in Southampton

What do rear extension planning drawings cost in Southampton?

As a guide, £1,000–£2,500 including VAT for a single-storey rear extension, or £2,000–£3,500 for a two-storey scheme. A householder planning application in England costs £548 (£575 for applications made from 8 December 2026), and a lawful development certificate for proposed work costs half the householder fee. These are guide ranges; the written quote after the survey is the figure that counts.

Do you need planning permission for a rear extension in Southampton?

The planning route for a rear extension in Southampton is set by England's householder rules and your council.

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.

Councils aim to decide householder applications within 8 weeks of validation, and prior approval within 42 days.

Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. Before any drawing we look up the property's history with the council, because earlier extensions and removed rights change the answer.

What are homes in Southampton like to extend?

Southampton 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 rear extension in Southampton 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. Options and costs

   We draw layout options and price each one, so the budget shapes the design rather than surprising you later.

3. Planning and regulations

   We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.

4. 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.

Rear extension planning drawings near Southampton

Neighbouring places we cover include Woolston (1.4 miles) and Portswood (1.7 miles).

• Rear extension planning drawings in Woolston
• Rear extension planning drawings in Portswood
• Rear extension planning drawings in Hythe
• Rear extension planning drawings in Totton
• Rear extension planning drawings in Hedge End

Other work in Southampton:

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

All rear extensions in Southampton