Designed for one or two persons, a granny flat is a self-contained living area usually located on the grounds of a single-family home. A granny flat can be detached, or it can be attached to the other dwelling. It is sometimes called a granny flat because it is a popular way for families to accommodate aging parents.
In the building industry, the granny flat is most often known as an accessory apartment or accessory dwelling unit.
Other terms include granny pod, mother-in-law unit, in-law apartment, bonus unit, casita, carriage unit and ohana unit (primarily in Hawaii).
Many granny flats fall into the tiny house category, and the surge in interest in tiny house living has been a boon to grandparents who are interested in this type of housing.
Granny flats / tiny houses may be used for nannies or for young adult members of the family. They are sometimes used as rental units, but zoning laws and deed restrictions sometimes ban renting.
As multigenerational housing becomes more accepted, granny flats are likely to become more prevalent. Realtors and builders report that they are already a good selling point.