How Much Does a Room Addition Cost in Denver, CO? [2026 Data]

The average cost of a room addition in Denver, CO, is $50,784, and most projects in the city total between $22,112 and $76,811. Your costs will depend mostly on the size of the room and the type of room you’re adding. Since the cost of living in the area is 25% above the national average, labor fees for planning and construction push average costs higher than you’d pay in most other cities.

Room Addition Cost Factors

A small bathroom or mudroom addition in Denver, CO, could cost as little as $7,406, but larger and more involved additions, like standalone ADUs, could cost $132,250 or more. Consider the following cost factors to get a better idea of where your total will fall within this range.

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, as each square foot you add to your living space will drive your cost up by around $85 to $215 per square foot. 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 $1,590 and $4,230 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 $52,900 on average, depending on its size and features. Larger bedrooms with more space, windows, and walk-in closets will all push costs up. 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 $23,300 in Denver 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 options for value. A half bathroom, which includes only a sink and toilet, takes up much less space and is a more affordable project, costing between $4,440 and $12,700.

Bedroom and Bathroom (Primary Suite)

The cost to build a primary bedroom with a bathroom ranges from $31,700 to $105,800, 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 cost well beyond the normal range.

Kitchen

A new kitchen installation costs between $37,000 and $100,500 in Denver, with prices averaging $68,800. 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 with a new foundation, framing, and exterior building materials, and it often adds new amenities. Bump-out additions cost around $4,230 to $31,700, 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 usually feasible in Denver, as the average lot size is 0.131 acres or just over 5,700 square feet. The average home is a little over 2,000 square feet, meaning there’s usually room for a bump-out without running into setbacks. You may not have this option, though, if you have an unusually large home or an unusually small lot for the area.

Dining Room

Are you looking to create a separate dining room or build a new version of your current dining room? Expect to pay between $3,170 and $52,900 in Denver. 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 $15,900 to $79,400, depending on the amount of work you need to do. A half-finished basement will take notably fewer materials, for example.

Most homes in Denver have basements, which are prevalent in colder climates, as they protect underground utility lines from freezing. As a result, finishing a basement is one of the most popular ways to add a room to a home in the city. It’s also a high-value project, as you get a large amount of usable living space without having to go through foundation pouring and major construction.

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 $10,600 and $52,900 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 $6,350 and $28,600.

Room Above the Garage

Adding a bonus room above the garage costs an average of $125 per square foot, with the average project totaling $47,600 in Denver. 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 $10,600 to $42,300 or more.

Laundry Room

Most homeowners in Denver pay between $5,290 and $7,400 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 $10,600 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 between $3,800 and $7,600, depending on the type of flooring and storage you add.

Mudrooms detract from usable living space and are sometimes an issue with property value in areas where square footage is limited. Luckily, the average home in Denver is over 2,000 square feet, so even a few dozen square feet dedicated to a mudroom won’t have a major negative impact on 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 $10,600 and $42,300.

Sunrooms are more popular in hotter climates where they remain usable for longer periods. They’re not nearly as prevalent in Denver, where the climate is relatively cool and winters are long and frigid. More residents opt for a bump-out addition tied into the main home’s HVAC system than a true sunroom addition.

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 $46,600 to $105,800, 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. At the end of 2024, the Denver City Council passed legislation that doubles the land on which ADU construction is legal, and ADU zoning is much more lax now than before. Most residents will have the option to build an ADU as a result, and most will have the space to build, given the average lot size of 0.131 acres in the city.

Remodeling Pro Costs

Between $20,300 and $30,500 will go toward labor alone when you add a room to your home using a remodeling company in Denver, CO. That means labor accounts for around 40% to 60% of your total. Hourly rates for labor, which scale with the local cost of living, are relatively high, as the cost of living in the city is 25% above the national average.

Materials and labor make up the bulk of your costs, but you’ll also need to budget for building permits, which the local building department requires for most room addition projects. The city charges $420 for the first $50,000 worth of work, plus $10 for each additional $1,000 worth of work. Given the average room addition cost in Denver, budget around $430 for permit fees.

Additional Pros to Consider Hiring

Room additions can sometimes require help from other professionals, like plumbers and electricians, if you need to tie utilities into your new space. You may need to consider the following labor costs, as well.

• Electrician: $1,220

• Plumber: $1,060–$10,600

• HVAC professional: $2,120–$3,180

• 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?

Adding a room to your home will usually increase home value, but your return on investment will depend on the type of room you want. You’ll see the lowest ROI from a mudroom addition, while a bathroom addition can fetch the highest ROI of up to 70%. In Denver, that would mean an average value bump of $16,300.

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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