Waffle Slab

Waffle Slab

Waffle slab is a reinforced concrete roof or floor containing square grids with deep sides and it is also called as grid slabs. This kind of slab is majorly used at the entrance of hotels, Malls, Restaurants for good pictorial view and to install artificial lighting. This a  type of slab where we find a hollow hole in the slab when the formwork is removed.  Firstly PVC trays (pods) are placed on shuttering then reinforcement is provided between the pods and steel mesh is provided at top of the pods and then concrete is filled. After concrete sets, the formwork is removed and PVC pods are not removed. This forms a hollow hole in it in which hole is closed at one end. The concrete waffle slab is often used for industrial and commercial buildings while wood and metal waffle slabs are used in many other construction sites. This is a one of the types of concrete slabs.

Where to use Waffle Slab & Waffle slab details:

A waffle slab has a holes underneath, giving an appearance of waffles. It is usually used where large spans are required (e.g auditorium, cinema halls) to avoid many columns interfering with space. Hence thick slabs spanning between wide beams (to avoid the beams protruding below for aesthetic reasons) are required. The main purpose of employing this technology is for its strong foundation characteristics of crack and sagging resistance. Waffle slab also holds a greater amount of load compared with conventional concrete slabs.

Advantages of Waffle slabs:

uWaffle slabs are able to carry heavier loads and span longer distances than flat slabs as these systems are light in weight.

uWaffle slab can be used as both ceiling and floor slab.

uSuitable for spans of 7m – 16m ; longer spans may be possible with posttensioning.

uThese systems are light in weight and hence considerable saving is ensured in the framework as the light framework is required.

Disadvantages of Waffle slabs:

uWaffle slab is not used in typical construction projects.

uThe casting forms or moulds required for pre- cast units are very costly and hence only economical when large scale production of similar units are desired.

uConstruction requires strict supervision and skilled labour.