The Average Room Addition Cost

Types

• The type of room addition is the largest influence on cost. For example, a half-bath will cost significantly less than adding a large family room to your home. Other common home additions include bedrooms, porches and second floors.

Features

• After the room addition is complete, you have to fill the room with furniture and other decor, from flooring to lighting fixtures. Your final room addition costs will be determined by the amount of materials needed and the quality of those materials. A do-it-yourself bathroom addition with basic fixtures, for example, can cost as little as $3,000, while a contractor-built luxury bathroom can cost upwards of $80,000, according to CostHelper.

Other Considerations

• Hiring a contractor can sometimes double or triple the cost of your room addition. Although contractors aren't necessary for basic building projects, you should hire a contractor if you have no experience with construction. Along with paying for the room addition materials and building fees, you'll have to pay increased property taxes on the value of the room.