The average addition in 2014 cost between $40,000 and $59,000. Costs for building an addition to a house vary based on location, the scale of the add-on and the cost of materials.
People primarily add on to their homes because they need more space, because building an addition is cheaper than purchasing a new home or because they want to increase the value of their homes. However, additions sometimes cost more than their return on investment because they are among the most expensive home improvement projects. In order to save money on the costs of additions, homeowners can incorporate existing or reclaimed materials.