How Much Does It Cost to Convert a Duplex to Single Family?

Average Cost to Convert a Duplex to a Single-Family Home

Converting a Duplex to a Single-Family Home Costs

Depending on your vision for your new home, converting a duplex to a single-family unit can be a small project, a massive undertaking, or something in between.

Architect and Floor Plans

Before you can start on construction to convert your duplex to a single-family home, you must first hire an architect to draw up a new floor plan for your space. The architect will visit your property, analyze the current layout, and then take into account circumstances like load-bearing walls, existing utilities, safety measures, and other building standards to create a new floor plan.

Depending on the scope of your project, your architect might charge a percentage of the total project cost or a flat hourly fee. Unless you plan to tear down a majority of the home, you can expect to pay architect fees of $125 to $250 per hour, and it might take 5 to 10 hours to complete the drawing of your plans.

Permits

Once you’ve got new floor plans in hand, you need to head to your local building or planning department to get a building permit. The types of permits you need and how much you’ll pay for them depends greatly on the scope of your project. Here’s an idea of the average permitting costs for various projects:

• General construction: $150-$2,000

• Plumbing: $50-$500

• Bathrooms: $175-$2,000

• Heating and air: $250-$400

• Windows: $50-$200

In addition to the permits necessary to complete various projects, you may also be responsible for inspection costs along the way. This is generally the case with larger construction projects that deal with plumbing and electricity. Depending on what the building department requires of you, expect to pay $200 to $500 in fees.

Construction Manager Costs

Construction managers generally charge a flat fee that’s equal to 5% to 15% of the total cost of your project. This means that if your project will cost $50,000 to complete, you can expect to pay a construction manager $2,500 to $7,500 to manage the project on your behalf.

Converting a duplex to a single-family home can be a huge job that requires strong coordination. If you don’t have the time to oversee the project or don’t have experience managing a construction crew, you need to hire a construction manager.

Construction managers are responsible for seeing a project to completion. They make sure the work completed by plumbers, electricians, and other professionals follow the blueprints you’ve provided. They’re also responsible for finding the pros to complete your project and keeping the remodel within budget.

Demolition

When completing a duplex conversion, removing a second kitchen is generally one of the requirements to have a multi-family home be reclassified as a single-family dwelling. It generally costs $2 to $7 per square foot to demo the interior of a home. This includes labor, equipment, and trash removal.

In addition to removing the second kitchen, you may have other demolition costs for additional projects that you may wish to complete. For example, you may want to knock down walls to create a living room, an extra bathroom, or additional bedrooms.

In some cases, you might want to tear down everything to the studs so that you can work with a clean slate.

The average costs to demo specific spaces of your duplex are as follows:

• Kitchen: $500-$3,000

• Bedroom: $500-$1,200

• Bathroom: $500-$2,300

The cost of demolishing a particular space varies depending on the complexity of the project. For example, bathrooms are generally more expensive because there are a lot of electrical and plumbing fixtures to work around.

Adding Walls

After you’ve completed the demolition of your duplex’s interior, it’s time to redefine your space by adding new walls. On average, you can expect to pay $20 to $30 per square foot for new framing and drywall costs. New drywall alone (assuming you’re reusing existing framing) costs $1 to $3 per square foot. If you prefer walls made of plaster, brick, stone, or concrete, the price can increase up to $80 per square foot.

Depending on how much demo you did, you might be building bedrooms, living rooms, and other spaces from scratch. If that’s the case, be sure to allow for $120 to $200 per opening for doors and pass-throughs. The cost of a new door generally runs $50 to $500, depending on whether you choose a basic interior door or something more elaborate.

Throwing up new walls may sound like an easy job, but it can actually be a complex one depending on the job. Simply hanging drywall is indeed a relatively quick task, but framing new walls and accounting for existing electrical work is more difficult.

Remodeling Rooms

Remodeling costs vary depending on how much you’d like to do. If the rooms are in relatively good shape and only require new flooring and a coat of paint on the walls, you could pay as little as $10 per square foot for remodeling.

However, if your rooms require more work, you could pay up to $60 per square foot for renovations. Of all the rooms in the house, bedrooms tend to be the cheapest to renovate as there are no appliances or cabinets, while kitchens and bathrooms cost the most.

If you like the placement of existing bedrooms and other areas, you might consider this option to modernize the space and save some money from your budget.

Adding Bathrooms

Adding a new bathroom to your space will cost more than adding a bedroom due to the plumbing that these spaces require. The average cost of adding a bathroom is $5,000, which includes plumbing and fixtures like a toilet, shower, and cabinetry.

An easy way to save money on the addition of a bathroom is to build it close to the previous location of the second kitchen. Plumbing will already be present, so this is one less (big) task that you have to worry about.

Adding Windows

When considering the cost of a new window, the greatest factor is the window itself. Fixed windows are the cheapest, averaging $65 to $700, while bay windows are among the priciest at $600 to $2,500.

Labor costs for installing a new window run $150 to $800 per window. Some contractors may charge an hourly rate of about $40.

As you create a new space during your duplex conversion, you may notice that areas that didn’t previously need windows now need them. This tends to be especially true when creating new living rooms and other places where friends and family gather.

Remove Front Door

It generally costs $320 to $760 to remove an old front door and seal up the existing opening. You may pay more if you have premium materials on your exterior wall such as brick or stone.

If you don’t like the position of either front door and wish to build a new one, expect to pay $860 to $2,550 to cut a new opening, frame it, and install the new door.

Some homeowners may opt to remove one of the doors when converting to a single-family home, but of course, you’re welcome to keep both if you have a use for two doors.

Electrical

Electricians generally charge $65 to $85 per hour for electrical work. Depending on what your home needs, you might need to pay for rewiring, running new wire, adding outlets and switches, and installing a new electrical panel.

Most duplexes are built with two electrical panels, one for each resident. When you convert a duplex to a single-family home, you’ll need to invest in the cost of electrical work to join the panels into a single one. This will make it so that you only receive one electrical bill rather than two.

Heating and Air

To save money (and your sanity!), consider adding the cost of a new HVAC system. You’ll generally pay $3,800 to $7,500, depending on the size of the unit you select.

You’ll probably need to join the ductwork from the two sides of the house so that your new AC sends air through the entire joined system. HVAC technicians typically charge $10 to $20 per square foot to work on ductwork.

As with electricity, you may need to complete some renovations to your heating and air system when you go from a duplex to a single-family home. Most duplexes do not share a single HVAC system between the two units.

While it’s perfectly fine to maintain two separate HVAC units for each side of your home, you’ll probably find it tiresome to control both thermostats. You’ll probably also deal with higher heating and cooling costs since you’ll be running two smaller units rather than one larger one.

Plumbing

Most plumbers charge $45 to $200 per hour. You may also be responsible for extra materials, depending on what you need done.

A plumber will help you combine two separate plumbing systems into a single one. Depending on your particular circumstances, this might be as simple as joining two sewer lines so that you receive a single utilities bill.

If you’re adding a laundry room, moving a bathroom, or doing some other kind of construction that requires a plumber’s expertise, you’ll pay more.

Decorating

The last step in converting a duplex to a single-family home is pulling the entire space together. You can accomplish this through your decorating efforts.

Depending on what you’re starting with, your new space might just need new outlet covers and a fresh coat of paint. In more extreme cases, you might be installing new trim, new flooring, and more throughout the house.

Here are average prices you might pay for common decorating ideas:

• Flooring costs: $3 to $22 per square foot

• Painting an interior costs: $2 to $6 per square foot

• Installing trim costs: $0.50 to $10 per linear foot

Converting a Duplex to a Single-Family Home Cost Factors

The factors that most greatly affect the cost of converting a duplex to a single-family home are the scope of the project, the quality of the materials you use, and professional installation costs.

Scope

When converting a duplex, you’re in charge of the scope of the project. Depending on your existing layout and your vision for the new space, you may have just a few simple tasks to complete or a massive job ahead of you.

Simpler conversions may just require the removal of a second kitchen and knocking down a few walls to create more accessible living spaces. More complicated projects could involve demolishing the interior to the studs and then radically changing the look of the space by creating new bedrooms and living areas.

Materials

The quality and quantity of materials you choose for your renovation have a huge impact on the total cost of your project. When building walls, you can save money by choosing drywall over plaster, but you have to decide which look you prefer.

The most expensive parts of a home to build or renovate are the kitchen and bathrooms. This is largely due to the large amount of electrical and plumbing work that need to go into these spaces. If you’re doing a complete overhaul, you’ll need to purchase new fixtures, appliances, and cabinetry, all of which vary greatly in price depending on the quality.

Installation

If you’re hiring professionals to complete your renovation project, you may need to find workers with highly specialized skills, such as plumbers and electricians. Depending on the scope of your project, you could be paying for many hours of this expensive experience.

DIY vs. Hire a Building Pro

Completing the renovations to turn a duplex into a single-family dwelling is best handled by a professional. Some tasks, such as rewiring electricity and moving plumbing, take specialized skills beyond the experience of most DIYers. Other tasks, like installing new flooring or painting walls, are jobs that you may be able to handle depending on your skills.

Beyond the actual work that needs to be completed, there’s also the task of managing the project: finding workers, ensuring jobs are completed to specs, and keeping an eye on the budget. This can be hard work because it requires a lot of organization and construction know-how. If you’ve never tackled a home renovation before, your money will be well spent on hiring professionals, including a construction manager, to do the work for you.

FAQs

Does it make financial sense to convert a duplex to a single-family home?

Whether it makes financial sense to convert a duplex to a single-family home depends on the local housing market and the value of the duplex. To decide whether this project makes sense for your needs, check the values of surrounding properties and compare it to the cost of renovating your home.

Is it legal to convert a duplex to a single-family home?

Your local building and permitting office is the authority on determining what construction projects are legal in your area. Before starting a construction project of the magnitude of a duplex conversion, you'll be required to obtain the appropriate permits. At that point, you can learn more about the laws in your city.