What Are the Different Types of Duplex Homes?

Duplex homes may be side by side or stacked. Within these two main categories, there are many different possible types such as single story or multi-story that can further be divided into ranch and mansion styles. A duplex home may feature two adjoining garages in the center of the design or have them at either end. Of course, some duplex housing doesn't include any garages within the design, but have only entry doors. Some duplex homes feature the entry doors in the middle of the house plan with one large covered roof over them.

Centered entries or garages may be horizontally level with the rest of the design, or the main housing units could be placed back from them. Typically, in side-by-side duplex homes, either the entries or garages form a shared wall between the two separate housing units. This type of duplex design can reduce the amount of noise between the units, as living area walls or floors aren't shared. A duplex home plan may place focus on providing the least amount of transferable noise between the two separate housing units, or it may have a more basic design of a completely shared wall or floor.

A side-by-side duplex with entries that are also part of the main building and not set back or forward will have a shared wall that may transfer noise quite easily. If these side-by-side duplex homes are multi-story types, the shared wall may divide bedrooms, bathrooms or other main living areas. Similarly, in stacked duplexes, a horizontal shared area, which is the ceiling of the lower unit and the floor of the upper one, may more easily transfer sound through the main living spaces.

Mansion, or block-style, duplexes may be either side by side or stacked in their home plan. Many of these are both, as they have multiple stories and adjoining entries. Of all of the different possible designs for duplex homes, this type is often the most difficult to tell that it's multi-family housing. Only looking at the two separate entry doors under the single roof at the front of the building reveals the "secret."

Ranch-style duplex homes are often more clear in their dual housing format. These single story, side-by-side duplexes typically have a reverse floor plan design that is quite obvious from the outside. The entries may feature separate, covered porches or paths to each front door.

There are many reasons someone may want to turn a duplex into a single family home. Leading the list is the changing housing market. The backlog of unsold homes cleared out long ago, and buyers are desperate to find something to purchase — and prices reflect this. Of course, there are other reasons, too. A duplex might be at just the right location or have historic value.

Regardless of the reason, there are a few things you need to do to get the process started:

Unless you’re highly skilled at reconstruction projects, getting the right contractor is usually the key step to building your dream house. They’re in big demand, so as soon as you’ve chosen your duplex, you should call one with a solid reputation and experience in duplex conversion. It may be many months before they can get to your project, so don’t delay this step.

Next, you should design your layout. You probably have many ideas before you even talk with your contractor and perhaps even a floor plan sketch, but an expert will need to look them over for practicality and feasibility. Local laws prohibit many ideas that homeowners have, like high cost or lot limitations, so expect changes to your early concepts.

Once the layout is known, you’ll have a price and can choose a lender if necessary. Then you can get the required permits and start construction.

The cost to build a new duplex varies dramatically based on location, quality and size, among other factors. A duplex will almost always be more expensive than a comparable single family home due to redundancies, such as two kitchens. Each dwelling also needs separate services, such as plumbing and electrical, which add to the expense.

A survey of national prices for new duplex construction indicates that the majority will fall between $250,000 and $500,000, with the most typical price being around $390,000 for two 900 square foot units. Once the land is purchased, labor and materials should be around 90% of the costs.

The cheapest type of duplex per square foot is the two-story stacked home layout, which is also called one up, one down. It’s efficient to build since each dwelling shares the same foundation and roof, and centralized plumbing and electrical significantly reduce material and labor costs.

Single story duplexes have substantially more cost per square foot than the stacked style. They require a larger roof, foundation footprint and land. The most expensive setup to build on average is the side-by-side style, although it’s also the most common.

The most significant impact on cost is the construction quality. Mansion duplexes often have outstanding noise abatement materials and stratagems, beautiful designs and curb appeal, while some low-cost ones are notorious for cheap materials and walls that block little sound.

Most conversions done by contractors cost between $50,000 and $99,000, with an average of around $80,000. These numbers may increase if the demand for contractors rises.

On the other end of the scale, it can cost as little as a few thousand dollars if there’s not much to change and you can do the work yourself. Call the zoning board or your attorney to figure out what’s necessary for your situation.

Many areas have strict definitions of single family and two family homes. For instance, each dwelling is commonly required to have a kitchen and bathroom to be considered separate. Conversely, homes may be considered multiparty if they have two full kitchens, but zoning laws have enormous variance across the nation.

Your contractor (or lawyer, if you do it yourself) can ensure that it’s legal to convert a duplex before work begins. Once the project is done and inspected, the property can be permanently designated as single family by the zoning agency. You can often get a great deal of free information just by calling your code enforcement and zoning agencies.