How Much Does a Room Addition Cost in Chicago, IL? [2026 Data]

The average cost of a room addition in Chicago, IL, is $49,728, and most residents pay somewhere between $21,652 and $75,214. Your total will depend mostly on the room size and type, as well as on whether you convert existing space or build new square footage with a bump-out. Residents should consider the above-average cost of living in Chicago, which translates to higher-than-average prices for room additions.

Room Addition Cost Factors

It’s possible to pay as little as $7,252 for a room addition in Chicago, IL, but some residents pay $129,500 or more for larger additions that demand plumbing, electricity, and HVAC connections. Consider the following cost factors to get an accurate estimate for your project.

Room Size

The size of your new room is one of the biggest factors that affect the overall cost, and each additional square foot of living space you want will add between $85 and $210 to your total. Basically, the bigger the room you want to add on, the more you can expect to pay for the project. Here's a breakdown of average prices.

Room Type

Different types of rooms have different installation requirements, which can tack onto the cost of your addition. For example, if you're adding a primary suite with an attached bathroom, you'll need to pay extra for things like bathroom plumbing, which can add between $1,550 and $4,140 to your total.

Here's what you can expect to pay, depending on the type of room you want to add.

Bedroom

A bedroom addition costs $51,800 on average, depending on its size and features. Larger bedrooms with more space, windows, and walk-in closets will cost more, while smaller bedrooms with fewer amenities will help keep costs low. Small bedrooms for kids or guests will be much easier on your wallet. Adding a bedroom can increase your home’s value and make it more appealing to potential buyers when it comes time to sell.

Bathroom

Adding a new bathroom costs around $22,800 in Chicago, but it significantly increases the value of your home. You can expect a 47% to 67% return on investment on your bathroom addition, making it one of the best options for adding value to your home. A half bathroom, which includes only a sink and toilet, takes up much less space and is a more affordable project, costing between $4,350 and $12,400. 

Bedroom and Bathroom (Primary Suite)

The cost to build a primary bedroom with a bathroom ranges from $31,100 to $103,600, but it can vary quite a bit depending on the details. For example, if you add a particularly large suite or high-end features, like custom cabinetry and marble countertops, the project can easily push costs beyond the normal range.

Kitchen

A new kitchen installation costs between $36,300 and $98,400 in Chicago, IL, with average prices sitting at $67,300. Certain features like islands and appliances account for a lot of that price, so it’s possible to cut expenses in many ways.

Bump-Out Addition

A bump-out addition expands an existing room with a new foundation, framing, and finishes, and it often adds new amenities. Bump-out additions cost around $4,140 to $31,100, depending on the amount of space you’re adding. Because there’s little electrical work and rarely any plumbing, bump-outs are more affordable than many additions.

Bump-out additions are popular in Chicago, but they’re not always possible. The average lot size in the city is just 0.098 acres, which leaves minimal space for bump-out additions, especially with average home sizes sitting over 1,700 square feet. Some homeowners may have plenty of room, but check with a remodeling company first to see if setback requirements will restrict building options.

Dining Room

Are you looking to createa separate dining room or build a new version of your current dining room? Expect to pay between $3,110 and $51,800 in Chicago, IL. High-end lights or chandeliers, a wet bar, and other amenities will add significantly to the price.

Basement

Finishing a basement refers to converting a basement space into a fully livable room complete with lights, heating, and more. The cost to finish a basement ranges from $15,500 to $77,700, depending on the amount of work you need to do. A half-finished basement will take notably fewer materials, for example.

Almost all homes in Chicago have basements, as a deep underhome area is required to run utilities and prevent plumbing lines from freezing in the extremely cold climate. As such, finishing a basement is one of the most popular room addition projects in the area.

Attic

Finishing an attic is similar to finishing a basement, although the addition tends to be simpler and less expensive. Most owners finish an attic to turn it into an extra bedroom, office, or lounging area. Expect to spend between $10,400 and $51,800 on the cost of finishing an attic. 

Garage Conversion

A garage can serve many purposes, but it’s often an excellent spot for a game room, extra bedroom, or office. It’s also a lower-cost project than many kinds of additions, with less wiring and plumbing work needed. Converting a garage to a room costs between $6,220 and $28,000. 

Room Above the Garage

Adding a bonus room above the garage costs an average of $120 per square foot, with the average project totaling $46,600 in Chicago. However, the cost varies based on factors like whether you need to build a staircase or change the structure of your existing garage. Significant structural changes can add $10,400 to $41,400 or more. 

Laundry Room

Most homeowners in Chicago pay between $5,180 and $7,250 on the cost of adding a laundry room to their home. However, if you decide to upgrade your appliances, replace or install a sink, or install more shelving, the cost can reach as high as $10,400 or more.

Mudroom or Entryway

Thanks to their small size and nonexistent plumbing requirements, mudrooms are often the least expensive rooms to add on. A 36-square-foot mudroom at the entrance of a home or a new entryway costs about $3,730 to $7,460, depending on the type of flooring and storage you add.

Adding a mudroom is a simple way to convert existing space for added utility, and it’s a popular option in Chicago, where home sizes are over 1,700 square feet and leave plenty of room for minimal conversion without sacrificing precious living area. Just be aware that a mudroom won’t add nearly as much value as converting existing living space to a bathroom or bedroom on a per-square-foot basis.

Sunroom

Depending on construction, a window-filled sunroom can serve as a play area, a second living room, or even a small indoor greenhouse. Expect the average three-season sunroom to cost between $10,400 and $41,400.

Sunrooms aren’t terribly popular in Chicago, as the cold climate makes the space less desirable and less usable for a good portion of the year. As such, this is a relatively uncommon room addition option in your area.

In-Law Suite

Adding an in-law room or rooms to your home can require numerous special considerations, including privacy and access concerns that could increase the project's cost. Adding an in-law suite costs around $45,600 to $103,600, depending on its size and complexity.

Another option for an in-law or guest suite to consider is building an accessory dwelling unit (ADU) or a home addition. ADU regulations in Chicago, IL, are generally favorable for homeowners, so most will be able to build one. However, the small average lot size in the city means you may not have adequate space.

Remodeling Pro Costs

The labor alone to add a room to your home will cost between $19,900 and $29,800 when you hire a remodeling company in Chicago, IL. On an hourly basis, you’ll pay more for labor than you would in most other cities, as the cost of living is 12% higher than the national average and drives labor fees up.

In addition to labor and materials, you’ll also need to budget for permit fees, which the local building department requires for major alterations like room additions. Expect to pay an average of $900 in permit fees, but note that this number can vary based on the work involved, so ask your pro for an accurate estimate.

Additional Pros to Consider Hiring

In many cases, building a room addition requires that you coordinate with multiple professionals. You may need to consider the following added fees, depending on the type of addition you’re planning.

• Electrician: $1,190

• Plumber: $1,040–$10,400

• HVAC professional: $2,070–$3,110

• Structural engineer: $75–$260 per hour

• Architect: $130–$260 per hour

• Foundation contractor: $10–$40 per sq. ft.

Does Adding a Room Increase Home Value?

Adding a room to your home will usually increase your property value, especially if you’re building a bump-out or converting an unfinished area, like a basement or attic, to living space. You’ll see the highest ROI when you add a bathroom, which can provide a return of up to 70%.

How Angi Gets Its Local Cost Data 

To help homeowners plan their next project, Angi provides readers with carefully researched cost data and upholds strict editorial standards. We start with national average project costs, which we collect by analyzing competitor information, retailer material costs, and input from professional contractors. We then apply local price index data to calculate location-specific estimates that reflect what homeowners typically pay in their local area. To do that, we use data from the U.S. Bureau of Economic Analysis (BEA), including its Regional Price Parities (RPPs), which measure price differences across cities. This helps us account for differences in labor, materials, and overall cost of living, so estimates in higher- or lower-cost areas better reflect real-world local pricing.

Every estimate undergoes a thorough editorial review to verify accuracy, consistency, and alignment with observed market conditions.

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