Architecture Q&A: what are the recent changes in "permitted development" regarding extensions?

Architect and interior designer Peter Morris answers your questions
Architecture cartoon
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Question: I am thinking of adding an extension to the back of my house. Can you explain the recent changes in "permitted development" regarding extensions?

Answer: Permitted development is a phrase for minor changes that owners can make to their homes without the need for planning permission. On May 30, the Government made some dramatic changes which will benefit many home owners. These changes will last until May 30, 2016.

A single-storey rear extension to an "attached" house can be extended by up to six metres (originally three metres) beyond the rear wall of the "original house" and eight metres (previously four metres) for a detached house.

The maximum height of a singlestorey rear extension has increased from three to four metres. However, these changes do require what is called a Neighbour Consultation Scheme. This requires the proposed designs to be submitted to the local planning department, incurring a very small fee (amounts vary between boroughs).

The process takes three to six weeks. If there are no objections from your immediate neighbours or the planners, you can proceed without planning permission. Of course, many rules have remained unchanged and these can be found at permission/commonprojects/ extensions.

The term "original house" means the house as it was first built or as it stood on July 1 1948 (if it was built before that date). Though you may not have built an extension to the house, a previous owner may have done so. Exclusions cover homes in places such as national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.

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Peter Morris is an architect and interior designer and a director of Peter Morris Architects, which specialises in modern, innovative and practical designs (

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