Single Storey Extension Plans – Understanding Permitted Development

Single storey extension plans do not always need to go through the planning permission process. However, it is important to check whether this is the case for any single storey extension that you are considering for your house. Doing so requires an understanding of the permitted development guidelines.

Changes in the planning laws mean that extension plans for single storey developments rarely need permission. However, they must be approved in terms of building regulations, and they must fall under the permitted development guidelines for single storey extensions. It is always wise to work through the guidelines and your house extension plans with an architect that has expertise with these extensions. However, a basic understanding is always a good place to start. For your single storey extension to fall within permitted development, the final new building must not take up more than half the land around the original structure. If your home is attached to another house, then your extension cannot go more than 3m beyond the original rear wall. The limit is 4m if your property is detached. But, these limits have been increased for some properties until May 2019. The increases mean that you can extend to 6m if attached and 8m if detached. However, these increases do not apply if you are in an area deemed designated land, or an area of specific scientific interest. There are also limits on the height of the extension, and on the height of the eaves. Additionally, it must be of similar appearance to the main structure.

If you are unsure as to whether you need planning permission for your single storey extension plans, then contact KJM Design and Planning Services today on 01375 267 888. Our team specialise in residential planning and design. You can find out more about us, the services we can provide, and about permitted development at