Waffle Slabs consist of coffers, or shaped voids, in soffits of slabs.

Information to provide in scheme design:

●     2-way waffle slab

●     Thickness of topping

●     Depth of ribs and distance of ribs from center to center

●     Size of flat beams

●     Clear floor height

Reasons to use this slab type:

Capabilities

●     Suitable for long spans

●     Voids can reduce the self-weight of slab

●     Accommodates space for services installation and distribution through slab openings

●     Flat beams can provide lateral resistance for wind loads

●     Provides robustness

●     Provides limited deflections

●     General aesthetics

●     Standardized formworks can be used to reduce construction time and effort

Disadvantages

●     Aesthetics of underside of slabs is dependent on workmanship

●     Service penetrations through rib beams will decrease their inherent strength and stiffness and can lead to reinforcement congestion within the beams

●     Long construction time needed to construct void formers and reinforcement placement

●     No stiffness or lateral system to resist lateral wind loads when there are no core walls in the design

●     Standard formworks used can be quite expensive for low-rise structures

●     More finishes work required for structures of large surface areas