Businesses specialising in prefabricated buildings design, manufacture, supply or assemble structures made partly or wholly from components produced off site. These may be delivered as flat-pack sections, panels or complete modules, then installed on prepared foundations. Materials commonly include timber, steel and concrete, with insulation, windows, doors and internal finishes incorporated during manufacture or added on site. The buildings range from garden rooms, sheds, garages and workshops to site offices, classrooms, changing rooms, healthcare spaces and larger modular buildings. Services may include planning the layout, adapting a standard design, arranging delivery, installation and connecting utilities. Some providers also offer foundations, accessibility features, heating, electrical systems and aftercare, while others supply the building only. The level of customisation, specification and installation support varies.