Rear extension planning drawings in Windsor

What do rear extension planning drawings cost in Windsor?

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. 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 rear extension in Windsor?

Here is how the rules in England apply to a rear extension in Windsor.

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 Windsor like to extend?

Windsor 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. Rear extension applications in Berkshire are householder applications, which councils aim to decide within about eight weeks.

How a rear extension in Windsor comes together

1. 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.

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 Windsor

Neighbouring places we cover include Slough (1.8 miles) and Egham (4.1 miles).

• Rear extension planning drawings in Slough
• Rear extension planning drawings in Egham
• Rear extension planning drawings in Burnham
• Rear extension planning drawings in Staines
• Rear extension planning drawings in Stanwell

Other work in Windsor:

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

All rear extensions in Windsor