Granny flat is simply a slang expression for accessory apartments in areas of single-family zoning; also sometimes referred to as mother-in-law apartments or maid’s quarters, they may or may not be allowed under zoning regulations.
Builders, such as Lennar Homes have jumped in to the Multi-Gen trend by building and offering homes with in-law-suites. The architectural plans below are taken from Pinterest under the search term multi-generational house plans. I Hope you enjoy them. CALL US if you are looking to locate or sell a home with an accessory unit or granny flat. That’s what OneRoofLiving.com is all about!
Attached Granny Flats
Nowadays, most granny flats are attached to the main house somehow. Some are simply a suite on the ground floor of a house, sometimes with a private entrance. These are essentially like a master bedroom, but with direct access to the outside. Other attached granny flats are more like a guest house, complete with a small kitchen. 
These are like a wing of the house, attached to the main house by a communicating door or hallway. Attics or basements are sometimes converted into granny flats, provided that the occupant can deal with stairs.
Detached Granny Flats
Many granny flats, especially on older properties, are detached from the main house. Some older houses or houses that sit on large lots have a separate granny flat out back, usually near the end of the backyard. This affords the occupant increased privacy and independence, while still being close enough to participate in the life of the family and for the family to keep an eye on their family member. Another common spot for a granny flat is above the garage. These are usually found on garages that are detached from the house, though there are exceptions.
Legal Issues and Zoning
There are zoning laws and occupancy regulations governing granny flats, which vary from place to place. Most communities have regulations regarding how big a granny flat can be, whether or not extra parking is required and where a granny flat can be located. There are also laws regarding whether or not rent can be charged and how much. Most municipalities require that the granny flat be considered part of the main dwelling and be under the same ownership; this means that single-family dwelling occupant density regulations apply. Owners of a granny flat or those looking to build one are responsible for knowing the regulations that apply in their community.
