One of the most cost-effective methods for adding a room to your home is to finish off an existing space. For example, if your house currently contains an unfinished basement, it can easily be transformed into a functional room which can be used as an extra bedroom, office, home gym, lounge or a family room.
Finishing up an existing space often costs less because the bones of the structure are already available. However, the walls may need insulation and framing, and flooring would typically have to be installed. In addition, you might expect to have some electrical and plumbing work done to facilitate the change of use.