How Much Does a Room Addition Cost in Baltimore, MD? [2026 Data]

The average cost of a room addition in Baltimore, MD, is $50,160, and most residents pay between $21,841 and $75,867. Your costs will depend mostly on the type of room you’re adding and the size of the new space. High labor costs due to the above-average cost of living in the area contribute to a relatively high room addition cost, but most residents opt to convert existing space rather than add new space to keep totals down.

Room Addition Cost Factors

Some homeowners in Baltimore, MD, pay as little as $7,315 to build a small room addition, but prices can climb up to $130,625 or higher. Your exact total will depend mostly on the following cost factors.

Room Size

The size of your new room is one of the biggest factors that affect the overall cost. Basically, the bigger the room you want to add on, the more you can expect to pay for the project, with each square foot adding between $85 and $210 to your total. 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 adds between $1,570 and $4,180.

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

Bedroom

A bedroom addition costs $52,300 on average, depending on its size and features. Larger bedrooms with more space, windows, and walk-in closets will all push costs higher. 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 $23,000 in Baltimore on average, but it significantly increases the value of your home. You can expect a 47% to 67% ROI on your bathroom addition, making it one of the best room addition types from a value perspective. A half bathroom, which includes only a sink and toilet, takes up much less space and is a more affordable project, costing between $4,390 and $12,500. 

Bedroom and Bathroom (Primary Suite)

The cost to build a primary bedroom with a bathroom ranges from $31,400 to $104,500, 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 beyond the upper end of the average range.

Kitchen

A new kitchen installation costs between $36,600 and $99,300 in Baltimore, with an average total of $67,900. 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 a current room outward, requiring a foundation and framing. Bump-out additions add square footage to your home, as opposed to conversions, and they often add new amenities. Bump-out additions cost around $4,180 to $31,400, 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.

While bump-out additions can provide an excellent return on investment, most homeowners in Baltimore won’t have much yard space to sacrifice for the build. The average lot size in the city is just 0.037 acres or 1,600 square feet, and the average home is close to 1,850 square feet, split between two levels. With local setback laws, large bump-out additions often aren’t possible, so this is a rare option in your area.

Dining Room

Are you looking to createa separate dining room or build a new version of your current dining room? Expect to pay between $3,140 and $52,300 in Baltimore. 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 $15,700 to $78,400, depending on the amount of work you need to do. A half-finished basement will take notably fewer materials, for example.

Basements are most popular in cold climates, where they protect underground utility lines from freezing. While the climate in Baltimore is relatively moderate, colder winters are common, especially by coastal city standards. As such, most homes in the city have basements, so finishing one is one of the most popular room addition projects.

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 $10,500 and $52,300 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 $6,300 and $28,200. 

Room Above the Garage

Adding a bonus room above the garage costs an average of $125 per square foot, with an average total of $47,000 in Baltimore. 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 around $10,500 to $41,800 or more. 

Laundry Room

Most homeowners in Baltimore pay between $5,230 and $7,300 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 $10,500 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 around $3,770 to $7,520, depending on the type of flooring and storage you add.

Mudrooms are most popular in areas where homes have above-average square footage, as sacrificing precious living space for the utility of a formal entryway can sometimes decrease home value. The average home in Baltimore is close to 1,850 square feet, though, so most homeowners will have enough space to build a mudroom without detracting from home value. Still, mudrooms don’t add much to your property value.

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 $10,500 and $41,800.

Sunrooms are most popular in warmer climates where they’re usable for longer periods of the year. The climate in Maryland includes long summers, so while the temperatures are moderate, sunrooms do have excellent utility. As a result, sunroom additions are also reasonably popular in the 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 $46,000 to $104,500, 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. In 2025, Maryland passed statewide legislation that made ADU legalization mandatory across municipalities. Most residents in Baltimore are legally able to build ADUs. However, the below-average lot sizes mean many homeowners won’t have ample space, so standalone ADUs are somewhat uncommon.

Remodeling Pro Costs

Between 40% and 60% of your total will go toward labor, which means around $20,100 to $30,100 in labor costs when you hire a remodeling pro in Baltimore, MD. On an hourly basis, labor costs more than it would in most other cities, as the local cost of living is 13% higher than the national average.

In addition to labor, your pro will charge you for permit fees to keep your room addition legal. These permit fees come from the local building department, and in Baltimore, they average $75.

Additional Pros to Consider Hiring

There’s a good chance you’ll need to hire additional professionals for your room addition project, especially if it involves tying in your existing utilities. You may need to consider the following local costs, as well.

• Electrician: $1,210

• Plumber: $1,050–$10,500

• HVAC professional: $2,100–$3,140

• Structural engineer: $75–$265 per hour

• Architect: $135–$265 per hour

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

Does Adding a Room Increase Home Value?

A room addition will usually add value to your home, especially if you’re creating additional living space either through converting an unfinished space or constructing a bump-out or ADU. The highest ROI will come from a bathroom addition, which can fetch a return of up to 70%. In Baltimore, where basement conversions are usually possible, converting that unfinished space to a living area can also provide a great ROI.

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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