Loft conversions can often be done without planning permission, providing your home has allowed development rights and you stick to the rules governing width, height, materials, etc. For example, you can not create additional roof space of more than 40 cubic meters in a terraced house, or 50 cubic meters in a detached or semi-detached house. If you want to make your plans fast and quality you can take a professional help from expert builders who will reliable convert your loft. But if you wanto make a loft conversion alone, it is a good idea to apply to your local council for a legal development certificate, which is for construction work that does not need planning permission.