Plaza decks are created in multiple forms with many distinguishable names—To name a few, there are Roofs, Floors, Driveways, Courtyard, and even Vegetative decks.
Plaza Decks can be located over parking areas, arcades, or water storage reservoirs, they may be extensive (the size of a city block) or small (just a square meter or two). Some plaza decks are above ground, while others may be sunken several meters below the ground. Regardless, they demonstrate design complexity.
Plaza decks are vulnerable to freeze-thatw and water damage, but they are often left out of the design of a building's waterproofing layers. Draining water from the surface is difficult, as the slope is minimal or sometimes non-existent. The transition between the steep wall (or planters) and the horizontal waterproofing should be carefully planned and built to avoid water infiltration. Still, this crucial detail too often becomes an afterthought.
The majority of plaza decks are constructed with cast-in-place concrete, often post-tensioned. Precast concrete is sometimes used, as are wood, metal, and combinations. Dead and live loads are impressive when you consider the load's weight and the deck's weight. The weight of planters and foliage as well as saturated soil can also make an impact.
The Whole Building Design Guide defines a plaza deck as any supported slab that provides green scape, tree planters, and pedestrian and vehicle movement over occupied spaces. More recent projects feature unoccupied space beneath —often storage.
Plaza decks are hybrids—the water protection system groups the characteristics of roofing and waterproofing. Protecting the waterproofing layer from temperature extremes, UV radiation, and mechanical damage is the focus in these systems. The The Whole Building Design Guide calls installations where the waterproofing is beneath the insulation a protected membrane or inverted roof membrane assembly. As a result, the underlying structure and adjacent spaces located below are also protected.