Rear extension planning drawings in Sunbury-on-Thames

What do rear extension planning drawings cost in Sunbury-on-Thames?

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. 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 rear extension in Sunbury-on-Thames?

Here is how the rules in England apply to a rear extension in Sunbury-on-Thames.

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. 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 Sunbury-on-Thames like to extend?

Sunbury-on-Thames 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 Sunbury-on-Thames 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. Approvals

   Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.

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 Sunbury-on-Thames

We also build rear extensions in nearby Walton-on-Thames (1.2 miles) and Shepperton (1.5 miles).

• Rear extension planning drawings in Walton-on-Thames
• Rear extension planning drawings in Shepperton
• Rear extension planning drawings in West Molesey
• Rear extension planning drawings in Hampton
• Rear extension planning drawings in Hanworth

Other work in Sunbury-on-Thames:

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

All rear extensions in Sunbury-on-Thames