An access birdcage scaffold consists of standards arranged at regular intervals in parallel lines, usually evenly spaced apart. These standards are laced together with ledgers and transoms at every lift to form a grid structure. The top lift, and often the perimeter bays of the intermediate lifts, are boarded to form access platforms for work on ceilings, sofﬁts and walls, for example to ﬁx lighting, ventilation or sprinklers. If the birdcage is to be used externally, or in an open structure exposed to the wind, it must be specially designed. A bespoke design is also required if the birdcage is to be used for purposes other than access, for example to prop a structure.