The average estimated cost for adding a room, such as a loft, is $40,979. It can cost as low as $21,717 or as much as $63,051, depending on the size, contractor fees and materials used.
The estimated cost for adding a loft could depend on the type of professional needed. If it is a simple loft being added to the outside of another room, where simple framework is needed, a contractor may be all that is needed. However, if the design is more complex and requires help from an architect, it can cost more. Some lofts and other home additions add value to a home, but not always. It is a good idea to get an appraisal for this type of project if part of the goal is to increase the value of the home.