Reinforced concrete slabs are supported by columns or load-bearing walls. Flat slabs are supported by columns with capitals and/or drop panels, while flat plates are supported by columns without capitals. This floor system also includes waffle slabs without beams. Slabs or plates can be post-tensioned. They are sometimes overlaid with lightweight roofing.

Reinforced concrete waffle slab, Canada (S. Brzev)

Reinforced concrete flat plate supported by columns, USA (S. Brzev)

Reinforced concrete roof slab supported by walls, Pakistan (J. Bothara)

Reinforced concrete flat slab system with capitals, UK (S. Brzev)