A reticular slab is a type of slab made up of a capsule of reinforced concrete ribs, of small width and at a short distance from each other, in such a way that the loads are transmitted in all five directions simultaneously. This system allows the beams to be eliminated, solidifying only the areas close to the supports. These solids are called capitals and are responsible for receiving the loads from the slab and distributing them across the columns.

Waffle slabs are reinforced concrete slabs, heterogeneous in terms of section, reinforced in two perpendicular directions and lightened.

These structures admit bending that can be decomposed according to the assembly directions, forming with the supports a spatial matrix with great capacity to collect vertical actions and with sufficient capacity for horizontal ones.

Waffle slabs do not have hanging beams, forming part of the so-called flat slabs, these being the most used in construction.

The basic parameters that define a waffle slab are:

In the edge areas, the slabs are closed with an edge beam called a perimeter ring (reinforced ring). In the case of encounters with the pillars, its configuration changes, becoming a solid slab called ABACO that avoids the risk of punching. This abacus is usually embedded in the edge of the slab, although in the case of large spans it may be thicker, being visible from its lower part. In this case, the ABACO is renamed CAPITEL.

There are different possible solutions: