What is a Duplex Home?

Malcolm Tatum
Malcolm Tatum

Duplexes, or duplex homes, are structures in which two housing units share a common central wall. In most cases, it is configured to allow the two units to share a common vertical wall, although there are some designs where the units are placed on separate floors, with the barrier servings as the floor for one unit and the ceiling for the ground unit. For the most part, a true duplex will occupy no more ground space than an average sized house, even though the structure provides living space for two households.

Many times, though it is the same structure, a duplex will have two separate mailing addresses.
Many times, though it is the same structure, a duplex will have two separate mailing addresses.

In actual practice, many people use the term duplex home to refer to any type of structure where up to four living units are connected by central wall. This is not completely accurate, since a two-story structure containing four living units would be more accurately referred to as a quadplex or quadraplex home. Those two terms are rarely used, however, and the building is much more likely to be referred to as a duplex apartment.

A duplex is when two housing units share a joint wall.
A duplex is when two housing units share a joint wall.

There are two basic building plans that can rightly be referred to as duplexes. The first and more common plan involves a structure that is two stories in height. The design is usually characterized by entrances for both units on the front and back of the building on the ground floor. Inside, the bottom floor of each unit will contain common rooms such as a living room, den, kitchen, bath, and dining room, while the second floor is reserved for full baths and bedrooms. This design is normally referred to as a full duplex.

The half duplex is another common design. It has no second floor for either of the two units, confining all living space to the main floor. As with the full duplex, each unit will have two entrances, although the design may call for side entrances instead of the more traditional back entrances. Half-duplex living spaces are usually more compact and better suited to singles or couples, while a full duplex can more easily accommodate a family.

A duplex home may be purchased as a single building, even if it carries two different mailing addresses. It is not unusual for owners of duplexes to live in one unit and rent out the other as a source of income. The laws in some metropolitan areas make it possible to treat both units as a separate house, however, making it possible to sell each unit in the duplex house to different owners.

Malcolm Tatum
Malcolm Tatum

After many years in the teleconferencing industry, Michael decided to embrace his passion for trivia, research, and writing by becoming a full-time freelance writer. Since then, he has contributed articles to a variety of print and online publications, including wiseGEEK, and his work has also appeared in poetry collections, devotional anthologies, and several newspapers. Malcolm’s other interests include collecting vinyl records, minor league baseball, and cycling.

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Discussion Comments


How many people can legally live in a duplex home?


The only duplex homes I've ever been in were very small. They were too cramped for my taste.

I like large rooms with plenty of space to move around in. Duplexes are mostly for city living, since there is such little space for building there.


@shell4life – No, they are supposed to be totally independent of each other. Each could function on its own if the other were removed.

My boyfriend lived in a duplex in town that had one living space on top and another beneath. He lived on the ground level, and he had his own kitchen and bathroom, as well as a bedroom and a living room. He had a staircase leading from the living room to the bedroom, and the bathroom was upstairs.

The second living space was located above his bedroom. I don't know if they had stairs in their place or not, but they definitely had their own bathroom and kitchen.


Do all duplex home plans give both living spaces a bathroom and a kitchen, or do they have to share these? Is there ever a common area in between the two that they both have to share?


@oasis11 – I feel the same way. My reason is because I find it hard to sleep when there is any noise around.

If I shared a wall with a neighbor and he had his TV on or snored loudly, I wouldn't be able to sleep. I like a lot of peace and quiet, even when I'm awake, so living in a duplex would be torture for me.


Sunny27- I agree that a duplex makes a great investment, but not all duplex homes are situated in urban areas. When I visit my sister in Coral Gables, I see many duplex homes in the area and Coral Gables is very upscale.

I guess it depends on the city. Tree lined streets much like a suburban neighborhood surrounds the duplex and multi-level apartment building. There are duplexes near the University of Miami, but that should be expected.

I personally would not want to live in a duplex because I don’t like the idea of someone else living so close to me.


Great article. I think that a duplex makes a great investment. Having two properties rented at the same time usually provides positive cash flow.

Duplex homes are less costly than apartment buildings and offer the new investor an opportunity to manage a smaller investment property and gain experience before considering larger units.

What I have found is that duplex properties are usually found in mixed use areas that share businesses as well as residential properties. These areas tend to be more urban and not as family oriented. But for a single person or a student, a duplex is ideal.

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