Home Addition by Type of Room
The room type you’re building is one of the first factors in determining your project cost. Rooms with plumbing, such as a kitchen or bathroom, are typically more expensive to add than rooms without, like a primary bedroom or sunroom.
Attic
Converting an attic into a livable space costs about $40,000. This conversion needs to have enough insulation and ventilation for comfortable year-round use. Plus, remember to account for the cost of installing a staircase in this room.
Bathroom
Adding a bathroom costs around $35,000, while adding a more luxurious and larger bathroom of 100 square feet will cost about $90,000. Bathrooms are a more expensive addition because they require plumbing, plus fixtures like showers and toilets.
Bedroom
A primary bedroom addition costs around $62,500, but if you’re planning to add an en suite bathroom, expect to spend up to $100,000.
Dining Room
A standard dining room is about 14-by-16 feet, and this costs about $20,000 to $45,000 to add to your home. Expect to pay more if you plan to add a wet bar or built-in cabinets and shelves.
Kitchen
A kitchen addition costs around $20,000 to $90,000. Kitchens are one of the most expensive home additions because they require electrical work, plumbing, and appliances.
Laundry Room
A laundry room addition costs about $8,070, including the cost of newer appliances, additional storage, and waterproof flooring.
Living Room
You’ll spend about $20,000 to $45,000 for a 12-by-18-foot living or family room. The cost will increase for larger rooms with high-end finishes and custom entertainment centers.
Mudroom and Sunroom
Mudrooms and sunrooms cost around $8,000 to $16,000. These are popular additions for added storage and living space. A 50-square-foot mudroom, including storage and built-in organization systems, costs around $12,000. Expect to spend $8,000 to $11,000 for a simple sunroom or upward of $80,000 for a 200-square-foot space with electrical wiring and heating.
Home Addition by StyleÂ
Home addition add-ons can vary by the style you choose. Balconies and bump-outs are generally more economical options and can sometimes be completed for as little as $5,000 to $10,000. On the more expensive end, an in-law suite can range from $50,000 to over $100,000, and a second-story addition can run between $300 to $500 per square foot. Below is a list of style options to consider.
Balcony
For the cost of a balcony addition, expect to pay roughly $5,000 to $10,000. Adding a balcony is a less expensive alternative to porches or decks if you want more outdoor space.
Bump-Out
A bump-out is an addition to a home's square footage—typically between a few feet and a single room—and a bump-out addition costs about $5,000 to $10,000. This is one of the least expensive home addition options, but it also tends to add the smallest amount of space to a home.
Cantilever
A cantilever costs around $15,000 to $25,000 and is an upper-floor home addition that juts out past the first floor. This style requires additional support beams either angled and attached to the house or anchored into the ground.
Dormer
A dormer addition costs between $5,000 to $10,000 and is a roofed structure that usually includes a window. It’s commonly added to increase a loft or attic's usable space and create window openings in a roof plane.
Garage
Adding a garage costs around $25,000 to $50,000, depending on whether you want an HVAC system and electricity. Adding a garage is ideal if you want covered shelter for your car, a space for handy work, or additional storage.
In-Law Suite
An in-law suite is a small studio or apartment that adds separate living quarters to your property. In-law suite additions cost around $50,000 to over $100,000.Â
Modular Room
Modular or prefabricated rooms will generally cost between $20,000 and $30,000, or around $25 per square foot. This is a less expensive option for a home addition because it's manufactured and delivered to your property, but it often has fewer customization options. Speak with a pro before adding a room to a modular home, as it may not be equipped to support an addition.
Porch
Building a porch costs between $5,000 and $25,000. A new porch can add extra square footage to your home while also offering space to take a breath of fresh air.
Second-Story Addition
A second-story addition costs upward of $500 per square foot and is one of the most expensive addition types because it requires removing and replacing the existing roof.
Home Addition by Size
Most home additions cost about $80 to $200 per square foot, including materials and labor. The cost is likely to be much higher for a second-story addition, at around $300 to $500 per square foot.