How Much Does It Cost to Build a Duplex?

By PropertyClub Team
Jun 15th 2024
On average, the cost of building a duplex can range from $220,000 to $400,000 or more, depending on the size of the property. Additionally, duplex building costs vary based on several factors, including location, materials used, and special additional features or finishes.

hash-markTable of Contents

What Is a Duplex?
Cost to Build a Duplex
Other Factors That Influence the Cost to Build a Duplex
Duplex Build Cost Bottom Line
Cost of Building a Duplex FAQs

hash-markWhat Is a Duplex?

A duplex is a type of residential property that contains two separate living units within a single structure. These units can either be side by side, sharing a common wall, or stacked one above the other, with each unit occupying a separate floor. 

Duplexes are popular among investors as they allow you to house hack, earning money by renting one unit out while living in the other.  

hash-markCost to Build a Duplex 

While the average cost to build a duplex is approximately $310,000, the exact price you will pay will depend on a number of factors. Here's what goes into the cost of building a duplex:

  1. Materials Cost: $40 - $60 per square foot
  2. Labor Cost: $100+ per square foot
  3. Other Costs: Varies

On average, it costs about $95-$220 per square foot to build a duplex. Let’s discuss the specifics that factor into that price.

1. Materials Cost: $40 - $60 per square foot

There is plenty of variety in the cost of materials when constructing a duplex. You can select a one-story duplex, a two-story duplex, and a side-by-side duplex. Each uses different materials, which factors into the average mentioned above.

No matter which style you decide to invest in, there are many materials you can expect to pay for with your creation. A few of these include:

  • Wood, which costs about $5.00 per square foot
  • Flooring, which costs about $8.00 per square foot
  • Foundation, which costs about $10.00 per square foot
  • Windows, which cost about $200 per window
  • Doors, which cost about $300 per door
  • Paint, which costs about $30 per gallon
  • Roofing, which costs about $4.00 per square foot
  • Siding, which costs about $5.00 per square foot

These are just a few materials costs you can anticipate.

Materials that make up a home account for a significant portion of the cost of building a duplex. Another portion is labor costs, which we will dive into next.

2. Labor Cost: $100+ per square foot

When you build a duplex, there are several labor costs associated with the construction process. These can add to the cost of materials to help approximate the cost.

Here are a few of the costs you can expect for laborers to build the home. You will need a:

  • Architects, which cost about $5,000
  • Plumbers, which cost about $10,000
  • Carpenters, who cost about $10.00 per square foot
  • Contractors, who cost about $85 per square foot
  • Painters, who cost about $3,000
  • Electricians, which cost about $3,000 
  • Excavators, which cost about $3,500

These are just a few of the people you will need to pay to create a duplex.

Labor and materials make up most of the costs of creating a duplex. However, there are also some price tags you should look at before committing.

3. Other Costs

The two costs mentioned above make up most of the fees you will pay. However, you should also think about a few other things.

Some extra costs that might come into play include:

  • Land price: Land can vary depending on the type and the location.
  • State: Certain states have higher taxes than others.
  • Layout: The layout of the duplex may make it more or less expensive.

These can add to your overall cost.

These factors are not the only ones that can affect the cost. Let’s talk about a few more things that you should expect.

hash-markOther Factors That Influence the Cost to Build a Duplex

Several other factors might influence the cost of the duplex. These are also critical to consider when determining how much money you need to set aside for creating this space.

Some of the other factors that might influence the cost include:

  • Need to demolish: You will pay more if there is an existing home you need to destroy ahead of time.
  • Interior design: An interior designer can make the space beautiful.
  • Technology: Want a smart home? Technology installation is extra.
  • Garages: Are you going to provide a space for cars or leave them in the driveway?

These can make your cost go up or down, depending on which factors you choose to include or exclude.

If you want to make a bare-bones duplex, it won’t cost you as much as if you decide to include complex technology or interior design features. Building on an empty lot will also be cheaper than demolishing an existing home. Consider these before you commit to the build.

hash-markDuplex Build Cost Bottom Line

The cost of building a duplex will depend on several factors, including the square footage, location, materials used, and finishes. You can expect to pay between $150 to $300 per square foot, depending on the complexity of the design and the cost of labor in your area. You should consult with a local contractor to get a more accurate estimate for duplex construction costs in your area.

hash-markCost of Building a Duplex FAQs

1. How much do you have to put down to build a duplex? 

Typically, you need to put about 15% down when building a duplex. It’s a little more than you would pay if building a traditional family home for one group to occupy.

2. How big of a lot do you need to build a duplex? 

To build a duplex, you need a lot that is at least 2.5 times bigger than the area, with 3.5 being the ideal size. You’ll have plenty of room with this size lot.

3. Is building a duplex worth it? 

A duplex is an excellent investment because you make more rental income on one than a similarly sized single-family home. Duplexes have the potential for high returns for investors. 

4. Is it cheaper to build a house or duplex? 

It costs more to build a duplex most of the time. However, a duplex will generate more rental income than a single-family home, which is why they are popular with investors. 

5. How do I start building a duplex? 

Check your local building codes and see if there’s room in the area. Acquire land and materials for the building process. Finally, design the duplex and contract out the work to get started.