Tension grid
A tension grid is a type of non-standard catwalk though it does not meet the structural standards of a traditional catwalk. It is composed of a tightly stretched grid of steel cables that create a taut floor that is strong enough for technicians to walk on.
Benefits
Lighting instruments can be hung on a pipe grid just above the tension grid; there is no need for holes, as the light can shine through the grid, virtually unobstructed, to the stage. Cables and electrical wires can pass through, and special fixtures may be used to allow beams and other solid material to pass through.
This style of catwalk is popular in new and remodeled theatres due to the flexibility it provides. Use of a tension grid does not require working off of edges as a traditional catwalk does, as lights are over the walking surface, not next to it. As a result, many consider tension grids safer in terms of risk of falling.
Costs
Tension grids require regular inspection. Lights shining through the tension grid light up a section of the grid itself, which some audience members find distracting. The cables of the grid absorb and redirect some of the light from a fixture, leading to a negligible loss in total light output. Working on a tension grid takes time to get used to because of the bouncing nature from walking across the surface. This motion coupled with the illusion of no floor at times makes it disconcerting to some.