Must Know Differences: ADU, Tiny Home, Backyard Home & Guest Home

Mar 23, 2022 | ADU

Additional dwelling units have been rapidly growing in popularity over the years. In 2020, The Federal Home Loan Mortgage Corporation (FHLMC) identified 1.4 million properties in the U.S. with ADUs. Growing at a popularity rate of 8.6% a year means that number has substantially increased. However, there has been some confusion about what constitutes an ADU. What is the difference between an ADU, tiny home, backyard home, and guest home?

An ADU is an additional dwelling unit you add to your primary property that contains a bathroom, kitchen, and living space to increase the value of your home. They can go by many names and differ from other structures in terms of regulations and use.

Are you interested in building an ADU but not sure if a tiny home will suit you better or possibly a guest home? Read on to find out the difference between ADUs and other structures people add to their property.


What Is An ADU?

Before we dive into what differentiates ADUs from other structures, let’s define what an additional dwelling unit is.

As a general rule, an ADU is a small residential unit that is built on a single-family lot that contains an existing primary home already on it. These units have been around for many years but have just become popular in the last few.

Every ADU has regulations dictated by the state and city the property exists within that has to do with height, square-footage, setback requirements, and the type of ADU. Contact your local planning office for help with ADU size limits and zoning laws for your area.


What Are ADUs Used For?

Additional dwelling units are built for a wide range of reasons including:

  • As an income opportunity by renting it out
  • As a place for guests to stay when they visit
  • To function as an office or workspace
  • To provide affordable housing in an area facing a housing crisis
  • To provide housing for aging family members
  • To provide housing for kids who want more independence

The ADU must provide bathroom facilities, kitchen, sleeping area, electricity, and means of entering and exiting the property (aka a walkway/driveway). The kitchen must contain a countertop, cabinets, a sink with running water, and a stove or stove hookup. If the ADU does not contain all of these, it will not classify as an ADU.


Types Of ADUs

There are four main types of ADUs.

  • Attached ADU
  • Detached ADU
  • Garage Conversion ADU
  • Internal ADU

Attached ADUs share a wall with the primary unit and are good if the purpose of your ADU is for multi-generational housing. Detached ADUs are stand-alone structures that are very common. Conversion ADUs convert a garage into an ADU and are the most affordable choice besides internal ADUs that exist within the pre-existing home.

Before you start to build an ADU yourself, you should take into consideration which type of ADU works best for your budget and needs.


What Are Backyard and Guest Homes?

Now that we know what an ADU is, it is time to see how it differentiates from other structures within people’s backyards like backyard homes and guest homes.

Backyard homes and guest homes are just other names for ADUs. The name differentiations are due to different people using different terms in different states. There is quite a difference between ADUs and tiny homes or sheds, but not a difference between guest homes and ADUs.

There is a long list of other names of ADUs including:

  • Accessory apartment
  • Backhouse
  • Backyard bungalow
  • Carriage house
  • Coach house
  • Cottage
  • Garage house
  • Granny flat
  • Guesthouse
  • In-law suite
  • Laneway homes
  • Ohana (popular in the Hawaiian Islands)
  • Secondary Dwelling Unit

All of these are additional dwelling units. These terms listed above are just “nicknames” for an ADU.


What Is a Tiny Home?

Although it is difficult to pinpoint an exact definition of a tiny home, they do differ from ADUs in several ways.

As a general rule, tiny homes are either small, fixed structures or small mobile units that may or may not contain wheels. They are illegal in most cities to have in your backyard for a variety of reasons, although there are exceptions.

Tiny homes cannot be connected to the grid unless in designated areas, like trailer parks. Most of them are not built to sufficient building codes, so they are unable to be connected to residential utilities, making it hard to have electricity to one in your back yard.

Not many cities allow you to have tiny homes in your backyard. Los Angeles is one of those cities that do permit it though. LA allows you to connect electricity to a mobile, tiny home in your backyard to combat their growing housing crisis. However, doing so is not likely to become very popular since ADUs are a more practical solution for most people.


Where Tiny Homes and ADUs Overlap

Tiny homes and ADUs can both be small (ADUs can go as big as 1,200 Sqf in CA). They are both ways to combat the housing crisis while being environmentally friendly by taking up less space. Since there is no clear definition of a tiny home, people who consider small permanent structures to be tiny homes could also consider them to be ADUs if they meet all of the ADU regulations.

This can be a bit confusing, which is why it is widely accepted that a tiny home is a mobile home. Once it becomes permanent in a specific place, it could become an ADU if it meets all the regulations necessary to be called one. That is if it is built on a lot with a pre-existing structure. Permanent tiny homes built off-grid or outside of cities that are built on their own plot of land are not ADUs.


Difference Between Tiny Homes and ADUs

Tiny homes are usually intended to be the primary residency, whereas ADUs are intended to be a secondary dwelling on a plot of land that already has a primary residency. ADUs are legal in many states and have intense rules and regulations surrounding them. Tiny homes, however, do not meet most building regulations in areas and do not have rules and regulations specific to them in most cities. Cities that do have laws that address tiny homes have laws that are extremely specific to that city.

The other main difference is that tiny homes are easily moveable. Most are mobile and found in trailer parks. Although they often look much nicer than a trailer home, they fall under the same category due to their mobility. ADUs on the other hand, are fixed permanent structures.


Building An ADU Yourself

If you are looking to build a dwelling in your backyard, your safest and the most legal option would be to build an ADU. Knowing where to start your ADU can be a tricky process though. This free ADU guidebook can be quite helpful with figuring out what ADU will work best for you and how to go about constructing your own.

Need more assistance and want more information specific to your needs? Consult with an ADU expert. Here at Levi Design Build, we can help explain the differences between ADUs, tiny homes, and other backyard structures. Our free consultation can help navigate you through permits, regulations, costs, and construction processes.

We can also help you navigate through ADU feasibilityADU financing, and even ADU development. We are committed to providing you with the highest service throughout the entirety of your project. Contact us today to get started on your ADU development!