The way in which a new space will be used is often overlooked when planning a one-off extension. The room an extension is built off can easily become little more than a corridor, with the result that a comparatively small amount of extra space is actually gained.

Think about how you and your family will circulate through both the existing and new spaces, and plan how these will be used and how furniture will be located so that the spaces flow. Where possible provide a link with the outside so the extension flows into the garden, creating a greater feeling of space.