It is not uncommon in a historic tax credit (HTC) project to need an expansion of a building at the roof to accommodate specific programmatic uses or to accommodate new building systems. Construction of habitable rooftop additions or the installation of rooftop equipment, such as new cooling towers, may be possible in a HTC project, provided the construction is designed in a manner that is sensitive to the historic character of the building and contemplates the context of the building and the visual impact of the new construction.