Businesses in the metal structures category make, supply and install structures formed from steel, aluminium or other metals. Work may include structural frames for buildings, industrial and agricultural buildings, mezzanine floors, platforms, walkways, staircases, balconies, railings, canopies and supporting frameworks. Some firms work from architects' or engineers' drawings, while others provide surveying, design development and detailed fabrication drawings as part of a project. Typical services include cutting, drilling, bending and welding metal sections and plates, assembling components in a workshop, and applying finishes such as galvanising or protective paint. Installers transport and erect structures on site, sometimes coordinating with builders and other trades. Businesses may also alter, strengthen or repair existing metalwork, replace damaged components, or fabricate bespoke items to suit a particular building or industrial use.