How Much Would It Cost to Build a Home Addition?

A home addition can boost the value to your home, and you can customize the addition to fit your needs. Costs can vary anywhere from $2,000 to $100,000 or more. When asking how much it would cost to build a home addition, take into account what room you're adding and if you're using existing floor space or adding floor space. Also, the quality of materials, whether or not you use existing accessories or purchase new ones and the complexity of the update will all affect the budget.

If you're adding new floor space, it would cost anywhere from $25,000 to $50,000 for a new bathroom. Of course, adding more high-end, spa-like features can bring the total well over $100,000. If you're adding a bathroom to floor space that already exists in your home, figure on a budget of $15,000 to $25,000. That seems like a lot for such a small room, but remember that, unlike most other rooms, you'll be using a plumber, which raises the cost significantly.

Building a bedroom can be a cheaper addition than other rooms because there usually aren't plumbing changes, complex architecture or expensive floor and wall treatments involved. A bedroom is generally smaller than a family room. If you're asking how much would it cost to build a home addition in regard to a bedroom, figure on $10,000 to $20,000 if a contractor will be adding the floor space. Adding a bedroom to existing floor space could run as little as $500 or as much as $5,000, depending on how elaborate you plan to make the space.

Adding a 400-square-foot family room, including new floor space, will cost roughly $25,000 to $50,000. Having a contractor build a family room using existing floor space, such as in your basement, would be $10,000 to $20,000.

How much would it cost to build a home addition that's a second floor? You can count on paying $75,000 to $400,000 depending on square footage. If you serve as your own general contractor (hiring and managing workers for the separate parts of the job, such as construction, plumbing and electrical), you can save as much as $100,000.

Online calculators and "guesstimates" are just that--guesses. They should only be used as general guidelines. You can get estimates from at least two local professionals to find out how much the work would really cost based on your needs, materials and location. When you ask contractors how much it would cost to build a home addition, you'll find that the estimates can vary greatly. These differences can be attributed to differences in labor costs and the quality of the materials used. It's helpful to have these specific costs spelled out on an estimate so you can see that while contractor A may have a lower bid, contractor B would actually give you better materials for your money.

When it comes to building a home addition, you want to consider more than just the cost. Improving your home can also increase its value, making the true cost of the renovations less than they appear to be. If you pay $25,000 for a new bathroom that adds $20,000 in value to your home, you're really only paying $5,000. Local real estate agents are great resources for finding out how much an improvement will increase your home value. Where you live and what addition you're making dictates how much you can expect to get back if you were to sell your house. For example, if you have a three-bedroom, one-bathroom home, adding a bathroom is going to add more equity to your home than adding another bedroom because two-bathroom homes are more desirable than one-bathroom homes.

You can bring down the costs of your home addition by doing some of the work yourself. If you have a second floor added (or a bedroom or family room), have the contractor do the framing and drywalling, then do the painting and install flooring yourself. For a bathroom, some relatively simple do-it-yourself projects include putting in the toilet (as long as the plumbing is complete), installing a vanity and doing the tile work or painting.