Home Extensions in Sunderland: Planning Permission & Costs

Published 1 April 2026 • By High and Dry Roofing

A home extension is one of the most effective ways to add space and value to your property without the cost and upheaval of moving house. Whether you need an extra bedroom, a larger kitchen or a home office, extending your home in Sunderland is a popular and practical option. Here is what you need to know about planning permission, costs and the build process.

Do You Need Planning Permission?

Many home extensions in England fall under permitted development rights, which means you can build without applying for full planning permission. However, there are strict rules about what is allowed:

• Single-storey rear extensions can extend up to 3 metres from the original rear wall for attached houses, or 4 metres for detached houses (or up to 6m/8m under the larger home extension scheme with prior approval).
• The extension must not be higher than 4 metres.
• Side extensions must be single storey with a maximum height of 4 metres and width no more than half the width of the original house.
• Two-storey extensions must not extend more than 3 metres from the original rear wall and must be at least 7 metres from the rear boundary.

You will need full planning permission if your property is in a conservation area, if you are a leaseholder, or if the proposed extension does not meet the permitted development criteria. It is always worth checking with Sunderland City Council before starting work.

Typical Extension Costs in Sunderland

Extension costs vary depending on the size, specification and complexity of the build. As a rough guide for Sunderland and the wider North East:

• Single-storey rear extension: £1,200 – £2,000 per square metre
• Two-storey extension: Slightly less per square metre than single storey, as you share the foundation and roof costs across two floors
• Side return extension: £1,500 – £2,500 per square metre depending on structural requirements

A typical single-storey kitchen extension of around 20 square metres might cost between £24,000 and £40,000 including all finishes, electrics and plumbing. Higher-end finishes, bi-fold doors and underfloor heating will push the cost towards the upper end of the range.

Building Regulations

Even if you do not need planning permission, all extensions must comply with building regulations. These cover structural safety, fire safety, insulation, ventilation and drainage. Your builder should submit a building regulations application on your behalf, and a building control inspector will visit at key stages of the build to check the work meets the required standards.

Party Wall Agreements

If your extension involves work on or near a shared wall with a neighbour, you may need a party wall agreement under the Party Wall Act 1996. This applies if you are building on the boundary line, excavating near a neighbouring property, or carrying out work that could affect the structural integrity of a shared wall. It is best to discuss your plans with your neighbours early and serve the required notices well in advance of starting work.

How Long Does an Extension Take?

A straightforward single-storey extension typically takes 8-12 weeks from breaking ground to completion. Two-storey extensions and more complex projects can take 12-16 weeks or longer. Allow additional time for the planning and design stages, ordering materials and any necessary approvals.