Once upon a time, open-air events were frowned upon. They were free, but facilities were typically sparse at best. Now, everything has changed. The sites are often enormous, ticket prices are eye-watering, and the stages can be impressive structures replete with cutting-edge technology.
Tensile fabric construction is sufficiently advanced to be the method of first choice, even for permanent stadiums and landmark buildings. They are the obvious choice for festivals, temporary arenas and mobile exhibitions because they’re light to transport, quick to erect and re-usable. Huge spans can accommodate events that are impossible to enclose any other way.
Staging often supports more than just performers. Bays may be needed for crews, changing rooms, guests and equipment. Much jargon exists among roadies and set designers to denote these annexe areas; guitar world, monitor world and dimmer beach are some examples.
Flooring can be several levels high, including lighting gantries and under-stage storage. In the early days of Glastonbury, savvy festival-goers arrived early to grab sleeping space beneath the stage.
Risers on casters provide quick scenery changes, and if drummers are hard to see, an 8×8 does the trick.
Vehicle docks must also be accommodated, with protection for the ground beneath their wheels.
Even temporary structures need to comply with safety regulations, and there are additional ones when audiences are enclosed, according to http://www.hse.gov.uk/event-safety/temporary-demountable-structures.htm.
Several construction options exist. Mobile stages with inbuilt flooring (for example, “Stageline”) are the fastest to erect but not as scalable as other types. Bil-Jax are 4×4-foot modular decking panels, often wooden within a metal frame. Aluminium-framed decking (for example, “StageRight” and “Tomcat”) are used when larger, sturdier stages are needed and are sometimes 8×4-foot. Steel stages are needed for A-list events with stages of 60 feet or more.
Permanent or not, roofs need local authority or approved contractor inspection before events can proceed, so specialists are needed. Companies like Fabric Architecture (http://www.fabricarchitecture.com/) can design a compliant fabric roof of almost any size.
Stages need roofs to hang lighting, sound equipment and signage; to protect performers and equipment from the elements and often to enclose the audience, too. The same is true of grander permanent arenas like opera houses, concert halls and sports arenas. Today, it is not unusual to find tensile roofed stages inside tensile roofed arenas.