A loft conversion can often be carried out without an application for planning permission – but there are conditions. Your home can’t be on designated land, and you can only add 40m3 to a terrace and 50m3 to a semi- or detached house. Previous additions do count. Materials must be similar to the existing house, and no part can be taller than the highest part of the existing roof. You can’t have a balcony under permitted development, either. For the full requirements, check realhomes.com/ planning-permission.