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How Much Does It Cost to Build a Duplex House (2023 Update)

Last updated 03/08/2024 by

Jamela Adam

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On average, duplexes cost between $95 and $220 per square foot to construct. Of course, these costs may vary drastically depending on the location of the property, what materials you use, and how you decide to furnish the space.
Duplexes are becoming a popular option for people looking to buy property. These houses are divided into two separate units but attached by a common wall. They can be an affordable option for families who need more space, or for people who want to generate some extra income by renting out one of the units. But how much does it cost to build a duplex house? What are the pros and cons of this type of residential property? And should you build a duplex from scratch or buy an existing one?
In this article, we’ll break the average costs of building a duplex in the United States, as well as the pros and cons associated with owning this type of property.

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What is a duplex house?

A duplex is a multifamily dwelling that consists of two separate living units. These two units share a wall and are built side-by-side where each unit has its own living area and entrance. Sometimes, the units can also be stacked on top of each other — one upstairs and one downstairs. In most cases, each unit in a duplex house is similar in terms of layout and amenities, but they can also be completely different.
Duplexes offer many of the same benefits as a traditional single-family home, such as ample living space and privacy. But they also come with some unique advantages, such as the ability to generate rental income while living in the duplex. By renting out one side of the duplex, owners can offset some of the costs associated with owning a home, such as mortgage payments, taxes, and maintenance costs.

How much does it cost to build a duplex?

The cost to build a duplex varies depending on a number of factors. These include construction costs, labor costs, material costs, the size of the structure, and the location. Recent data shows that it’s possible to build a duplex for between $95 and $220 per square foot. As of today, the national average cost to build a typical 3,000-square-foot duplex is around $285,000 and $537,000, with most people paying around $388,000.
Of course, the cost of furnishing and decorating the units will add to this total. Nevertheless, building a duplex is generally much less expensive than constructing two separate single-family homes. And if you rent out one of the units and live in the other one, you can build equity and passive income to recover the duplex construction cost.

Labor costs

To get a better understanding of the potential labor costs, consult with a general contractor or other building experts. In general, the labor costs for constructing a duplex home can vary significantly depending on the property’s location, size, and complexity of the entire project.
Here are some subcontractors you can expect to work with:
% of duplex costAverage costLow-endHigh-end
Architect10% – 15%$38,800 – $58,200$14,250 – $21,375$110,000 – $165,000
Structural engineer$500 – $20,000$500 – $20,000$500 – $20,000
General contractor25%$97,000$35,625$275,000
Foundation8% – 10%$31,040 – $38,800$11,400 – $14,250$88,000 – $110,000
Framing the structure10% – 12%$38,800 – $46,560$14,250 – $17,100$110,000 – $132,000
Walls and exterior6% – 10%$23,280 – $38,800$8,550 – $14,250$66,000 – $110,000
Roof construction8% – 12%$31,040 – $46,560$11,400 – $17,100$88,000 – $132,000
Windows and doors installation3% – 7%$11,640 – $27,160$4,275 – $9,975$33,000 – $77,000
Finish interior6% – 10%$23,280 – $38,800$8,550 – $14,250$66,000 – $110,000
Flooring3% – 5%$11,640 – $19,400$4,275 – $7,125$33,000 – $55,000
Finish interior features3% – 5%$11,640 – $19,400$4,275 – $7,125$33,000 – $55,000
Install bathrooms3% – 5%$11,640 – $19,400$4,275 – $7,125$33,000 – $55,000
Install kitchens6% – 10%$23,280 – $38,800$8,550 – $14,250$66,000 – $110,000
Electrical work8% – 12%$31,040 – $46,560$11,400 – $17,100$88,000 – $132,000
Plumbing work10% – 14%$38,800 – $54,320$14,250 – $19,950$110,000 – $154,000

Material costs

When it comes to material costs, building a duplex is no different than any other type of construction project. You’ll need to factor in the cost of lumber, concrete, plumbing fixtures, electrical wiring, and so on. But with a bit of creativity, you can save money on some materials.
For example, you can use recycled lumber from an old deck or fence, or even salvaged flooring or cabinets from a remodeling project to reduce the overall cost.

Pro Tip

Depending on where you live, you may need to get certain permits to build a duplex. Some of these include a demolition permit, an electrical permit, a general building permit, and a plumbing permit. So be sure to check with your local building department and factor in the additional costs before proceeding with your project.

Where you live

In general, the cost of materials, land, and labor is much higher in urbanized areas compared to rural areas. For example, building a duplex in the Silicon Valley area will almost always be more expensive than building it in the rural parts of Texas.
There’s a lot that goes into buying the right plot of land for your duplex construction, such as zoning, deed restrictions, and easements. If you aren’t familiar with the process of purchasing land, make sure to work with a real estate agent who specializes in the field.

Number of rooms

The cost of building a duplex depends on how many bedrooms, bathrooms, and other spaces you plan to incorporate into the layout. Without a doubt, adding a second bathroom or bedroom will increase the overall cost of the project.
Any high-end finishes such as granite countertops and hardwood floors will also drive up the price. However, better finishes can also increase the price of a rental, meaning you could take in more rental income and pay down those duplex costs. So be sure to work with a qualified contractor who can help you develop a realistic budget for your project.


When you’re planning to build a duplex, there’s more to think about than just the building itself. You’ll also need to factor in the cost of furnishing each unit.
The average cost to furnish a house can range anywhere from $3,500 to $95,000 — with the national average cost being $16,000. Of course, this can vary depending on your desired layout and the property’s square footage. If you want to go for a more high-end look or hire an interior designer, prepare to shell out a bit more money.
If you need some extra cash to pay for nicer furniture or high-end fixtures, consider taking out a personal loan. Using the comparison tool below, you can compare interest rates and credit score requirements to ensure you’re getting the best deal.

SuperMoney may receive compensation from some or all of the companies featured, and the order of results are influenced by advertising bids, with exception for mortgage and home lending related products. Learn more

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The pros and cons of owning a duplex

Before taking the plunge to build a duplex house, be sure to carefully weigh the pros and cons of this type of residential property.
Here is a list of the benefits and drawbacks to consider.
  • More privacy. As semi-detached houses, duplexes typically offer a higher level of privacy than apartments or condos because each unit has its own separate entrance.
  • Rental income. Because there are two units in a duplex, you can rent out one or both units to generate additional income. Doing so can be a great way to build equity since your tenants can help pay for a portion of the mortgage. It’s also an affordable way to get started in real estate investing.
  • Multi-generational living. Duplexes can be a great choice for multi-generational living. With two separate units, families can have their own space while still being close to one another.
  • Rental income isn’t guaranteed. One potential downside of owning a duplex is that rental income isn’t guaranteed. If you have an empty unit, you won’t be able to rely on that income to help cover your mortgage payments. This can leave you in a tight financial situation if you’re not prepared for it.
  • You’re responsible for repairs. If you rent out your duplex, you’re responsible for keeping up with repairs. If something breaks, it’s your job to fix it. This can become expensive, especially if you have multiple units.
  • Dealing with neighbors or tenants. While it’s possible to get along well with your neighbor or tenant, there’s always the potential for disagreements that can make living in close quarters difficult.

Duplex cost by construction style

When deciding on which type of duplex to build or buy, there are two main options: side-by-side duplexes or stacked duplexes.

Stacked duplex

As opposed to the more traditional horizontal layout of most duplexes, the units of stacked duplexes are vertically aligned. To put it simply, they’re built on top of each other, often with a shared staircase connecting the two units. These types of duplexes are quite popular in urban areas where space is limited.


As its name suggests, a side-by-side duplex is a one-story duplex that contains two dwelling units. These units are built right next to each other with a shared wall in between.
These types of duplexes tend to be more popular with buyers compared to stacked duplexes mainly because most people dread the idea of having a noisy neighbor living right on top of them.


Is a duplex worth buying?

Duplexes can be worth buying because they offer the potential for rental income. You can live in one unit and rent out the other, which helps offset the costs of homeownership. But it’s also important to remember that being a landlord comes with its own set of responsibilities, such as maintaining the property and collecting rent.
You’ll also need to make sure you’re in compliance with any regulations regarding rental properties. So before making a decision, sit down and weigh all of the pros and cons of having a duplex.

Is it cheaper to build a house or buy a house?

According to data compiled by the National Association of Home Builders, it’s usually cheaper to buy an existing house instead of building one from scratch.
But still, the decision of whether to buy or build comes down to your needs and preferences. When you build a new home, you’re able to customize every tiny detail to your specification. You get to pick the location, the design, the materials, fixtures, etc. On the other hand, buying existing homes requires less effort since they’re already done for you. You also don’t have to worry about dealing with contractors and the hassle of getting permits.

What does a duplex house look like?

Some duplexes are built as a mirror image of one another, with each side identical in layout. But in many cases, there can be some variations in terms of size and amenities. For example, one side of the duplex might have a front-load garage while the other side has a side-load garage.
Typically, each unit of a duplex has its own entrance, although there may be a shared driveway or patio area. In terms of style, duplexes can range from traditional to contemporary, depending on the owner’s preference.

Key Takeaways

  • A duplex is a multi-family property with two separate residences that share a common wall. The units can stack on top of each other or be built side by side.
  • The national average cost to build a duplex is between $285,000 and $537,000 for a 3,000 square-foot two-story duplex.
  • Duplexes offer more space and privacy compared to apartments, and can also be a great way to generate passive rental income.
  • There are some downsides associated with renting out one unit of your duplex. For one, you might have to deal with noisy tenants. You’re also responsible for keeping up with repairs and maintenance. Plus, the property won’t always guarantee 100% occupancy.
  • Generally, it’s cheaper to buy an existing house than to build it from scratch. But ultimately, whether to buy or build a property will depend on your personal needs and preferences.

SuperMoney may receive compensation from some or all of the companies featured, and the order of results are influenced by advertising bids, with exception for mortgage and home lending related products. Learn more

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