In the main - no. The vast majority of the time, garden rooms do not usually require a planning permission as they fall within "Permitted Development" rules. This is pre-approved planning permission - as long as your garden room is built subject to a number of limits and conditions. Check out our Planning Rules & Building Regulations page. It gives you all the details you need to know. You can also check the latest UK government regulations which, if updated, will be viewable on this link.