How Much Does a Bump-Out Addition Cost?

Average Cost to Bump Out a Room

What Is a Bump-Out Addition?

Bump outs are smaller extensions than full-blown additions, and they're always an extension of an existing room rather than a completely new room. Bump outs extend an existing space, and range from 2 to 15 feet wide, so they can easily add significant space to your home. 

People commonly bump out a kitchen for extra counter space, floor space, or to comfortably fit a dining area. Others opt to bump out a bedroom to provide a walk-in closet or to accommodate a new family member. Mudrooms are another popular bump-out option. Building a mudroom costs $8,000 to $16,000. But, consider that a typical small, 50-square-foot mudroom would only cost $4,500 to $10,000 as a bump out. 

Because bump outs are expansions rather than additions, they cost significantly less than the price of building a new home addition. That’s because it requires fewer materials and no additional heating and cooling. Plus, if the bump out cantilevers off the existing joists, you also save on the cost of laying a new foundation and everything that goes along with that, including excavation and grading. House framing costs are also substantially lower, as only a small area requires framing for a bump out. 

Cost to Bump Out a Room by Size

While adding just a couple of feet to the width of a room doesn't seem like much, it can add significant square footage to your space. 

A 2-foot bump out that runs the length of your 15-foot kitchen adds 30 square feet, which is a 20% size increase. This would give you plenty of room to install a breakfast nook or add a generous kitchen island and space for an extra appliance. 

A 3-foot bump out in a 30-foot living room gives you a whopping 90 square feet of extra space, which is plenty for a small home office, book nook, or craft area. 

Factors That Influence the Cost to Bump Out a Room

Size is the main factor that influences the cost to bump out; most pros price per square foot. The cost of bump outs compared to the cost of full home additions is less because you don't need to worry about extra insulation, plumbing, electrics, lighting, foundation, or supports. But there are other costs that add to your total budget for a bump out.

Finishing the Space

Once the bump-out construction has finished, you've got to finish the space before you can outfit and furnish it. This adds to the total project cost.

Flooring

In most cases, installing new flooring costs $3 to $22 per square foot. However, there are loads of flooring options, and you'll want the flooring to match the existing space. But this could also be a good time to install new flooring in the whole room. For bump outs that are their own space, like a home office, laundry room, or craft space, you have more flexibility with flooring choices. On a tight budget, laminate flooring is a good choice. For warmth, carpet or hardwood is the better option. In bathrooms, go for tile flooring. 

Decorating

As well as flooring the bump out, you'll also need to decorate the bare walls. Just like with the flooring, if the bump out needs to match the larger room, you have limited options unless you plan to update the entire room’s look, which could save you money in the long run. For example, when the bump out is ready for finishing, it's a good opportunity to redecorate as part of the cost to remodel a living room, rather than trying to match the bump out to the existing decor, then remodeling the whole thing in a few years.

Here are some common decorating additions and their associated costs.

• Painting walls costs $2 to $6 per square foot

• Wallpapering costs $4 to $10 per square foot

• Wainscoting or beadboard installation costs $5.50 per square foot

• Baseboard installation costs $6 to $9 per linear foot

Windows

Installing windows costs $3,500 to $9,900, depending on the size and number of windows. Most people pay toward the lower end of this range for bump outs. If your bump out adds to a bay or bow window and seating area, expect to pay between $800 and $15,000, all-in, for the cost to install a new bow or bay window, including the window panes and the bump out. 

Electrical

While not always necessary, hiring an electrician costs $50 to $100 per hour. You'll need to hire a local electrician if the bump out requires additional lighting, outlets, or a ceiling fan. 

Outfitting the Space

Depending on which room you bump out and what you plan to do with the extra space, you'll need to budget for the materials and installation required to appropriately outfit the space.

Kitchen Cabinets

If you've decided to extend your kitchen and you need some new cabinetry to fill the space, you'll pay $50 to $750 per linear foot for materials and hardware. Once you add in the price of labor, installing new kitchen cabinets costs $100 to $300 per linear foot for standard stock and up to $1,200 per linear foot for custom cabinets.

Window Seat and Bookcase

Installing a built-in bookcase costs $150 to $1,200 per linear foot, all-in, though the price depends on whether you choose a pre-made unit or have a custom design. If your bump out is a bay window or a similar type of light, airy out-of-the-way space, and you'd like to turn it into a reading nook, aside from getting a plush, comfortable window seat or armchair, you'll need to think about installing a bookshelf. 

Home Office

While a home office doesn't necessarily need anything built in, it does need an appropriate desk, chair, and tech setup if you don't already have them, so a setup customized to your needs can cost anywhere from $300 to $5,000. Designing a home office takes careful consideration of your working style and needs, so don't rush into things. If space is truly limited, you could install a wall-mounted fold-up desk suitable for a laptop or tablet. 

If you need something more robust to house your desktop, files, and other work-related paraphernalia, choose a desk with plenty of storage space, maybe with a custom-built hutch to use the vertical space. You'll also need really good lighting to avoid eye strain. Installing light fixtures costs between $150 and $800.

Craft Space

If your bump out will become your crafting haven, then just like a home office, you need to customize it to the crafts you love and prioritize good lighting. You could pay anywhere from $100 to $10,000 for a custom craft nook. Most crafts come with a lot of bits and pieces, so plenty of storage is a must. 

You can hire a cabinet maker, get quotes from a local handyperson, or find a nearby carpenter to design custom storage solutions, or you can purchase and install pre-made units that you can configure to your exact needs. And don't forget the desk. For most crafts, you need a large, clear surface to work on.

Bathtub

If you've increased the size of your bathroom because you want to add a nice tub, you'll need to budget for the cost of the tub. The cost to install a bathtub ranges from $600 to $14,000. If you want the ultimate luxury of a marble or cast iron tub, remember that the sheer weight of these items may mean you have to pay extra to get additional structural support for your bathroom floor. Additionally, these are so heavy that you may not be able to locate them in the bumped-out area.

DIY vs. Hiring a Pro to Bump Out a Room

Bumping out a room isn't a job for an amateur. If you get it wrong, you can cause extensive damage that will cost you significantly more to repair than the bump out would've cost to begin with. It's also a huge undertaking. You're far better off hiring a construction manager or general contractor to take care of the whole project for you. 

If you do want to minimize costs, you can take care of much of the finishing yourself, including hanging drywall, wallpapering and painting, adding wainscoting and baseboards, and outfitting the space if you have the time and the skills. But for everything else, rely on the pros.