# Difference between One way slab and Two way slab

We all know that (L/B) ratio to find the given slab is one way slab or two way slab.

It’s not that critical to find that. Just understanding the basics will do the magic.

Let’s Begin !!!

One way slab definition

What is one way slab?

According to IS 456:2000, The ratio of longer span(l) to shorter span(b) which is (L/B) greater than 2 is known as One way slab.

In practical, One way slab is supported by only two parallel beams or walls.

Normally we don’t use one way slabs often. We use them on cantilevers and shajjas/lintels

One Way Slab Reinforcement Details

The main reinforcement bar will be provided in the shorter span where the bending moment will be high as shown in the drawing.

The distribution rods will be provided in the longer span for the load distribution purpose. We have discussed the difference between main reinforcement bars and distribution bars.

Two way slab definition

The ratio (L/B) which is less than 2 is known as two way slab. Two way slabs are normally supported from four sides.

Two Way Slab Reinforcement Details

Difference Between One Way Slab & Two way slab

• L/B>2 is one way slab L/B<2 is two way slab
• One way slab is supported by two parallel beams or walls; Two way slab is supported by four sides
• Main reinforcement will be provided on one side; Main reinforcement will be provided on both sides (sometimes).

Hope this helps. Happy Learning 🙂