Granny flats are completely self-contained home extensions that are constructed on the same plot of land where the main home is situated. Aluminium windows and doors are used to construct granny flat. It is basically a smaller version of a home located on the same property. Such types of flats are to be found behind the main house and they might have a common backyard or a separate section of the yard can be marked off. They generally contain a kitchen/kitchenette, living room, bedroom, bathroom, and laundry room that can be separate or combined with the bathroom and kitchen. You have to talk to the local council to find out the maximum size of a granny flat that can be built on your property.