The term garden flat is synonymous with garden apartment and basement apartment, all of which refer to a residence that is located on the bottom level of a building. The entrance to this residence may be level with the street or may be reached by walking down a short flight of stairs. This also means that the floors of a garden flat may be either on approximately the same level as the street or slightly below that level. The term garden flat is usually used to refer to the most nicely-appointed versions of these residences, ones that are connected to a garden that is usually located at the back of the building. The term has been appropriated, however, in the world of real estate to simply describe bottom level apartments, some of which are not connected to any gardens at all.
In the nicest examples, garden flats are arranged to maximize the amount of natural light that filters into the space and optimize the connection between the residence and the garden. The garden might include a patio where the residents of the flat eat their meals when the weather is fair. It might also include large sliding glass doors that offer a nice view of the garden and also allow a great deal of light to enter the living space. Depending on the arrangement of the building, the resident of a garden flat may or may not have exclusive use of the garden. There are some cases in which residents of apartments on upper levels also have access to the garden.
In some places, living on the bottom level of a building is considered to be a bit dangerous. This is because the bottom level is the easiest level to break into. In these places, it is common for a garden flat to be outfitted with barred windows and security systems. Even if the apartment is nicely appointed, a garden flat might be less expensive to rent or buy because of this issue. In areas of low crime, this is not a concern.
Some people who decide to build or remodel their homes will outfit the bottom level as a garden flat. There are a few reasons to do this. One is to create a separate living space for a family member such as a parent or a sibling. Another reason is to create a rental property that can be used as a source of income or as a way to help pay the mortgage.