Rear extension planning drawings in Portsmouth

What do rear extension planning drawings cost in Portsmouth?

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 Portsmouth?

Whether your rear extension in Portsmouth needs a planning application depends on its size, your house and any local restrictions.

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. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.

What are homes in Portsmouth like to extend?

Commuter semis and detached houses make up much of Portsmouth, and longer gardens make England's prior approval route for deeper rear extensions worth considering.

How a rear extension in Portsmouth 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. 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 Portsmouth

Neighbouring places we cover include Southsea (1.1 miles) and Gosport (1.7 miles).

• Rear extension planning drawings in Southsea
• Rear extension planning drawings in Gosport
• Rear extension planning drawings in Cosham
• Rear extension planning drawings in South Hayling
• Rear extension planning drawings in Fareham

Other work in Portsmouth:

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

All rear extensions in Portsmouth