What is the difference between strength and stiffness?

What is strength?

Strength is the ability of a material to resist forces without breaking or permanently deforming. In floor gratings, for example, this refers to the bearing bars that must be able to withstand heavy loads without buckling, tearing, or breaking. Strength is expressed in kilonewtons (kN), which indicates the maximum load that a grating can withstand before structural failure.

For a reliable assessment of these properties, you can use our strength calculation tools for gratings, stair treads, and perforated panels. These provide a quick insight into the load-bearing capacity of the selected product type, tailored to your project requirements.

What is stiffness?

Stiffness has nothing to do with failure, but everything to do with deflection. It describes how far a material deforms elastically when a force is applied to it. A grating can therefore be strong enough not to break, but still deflect too far – and that can negatively affect the safety and comfort of users. 

We measure stiffness in millimeters (mm) of deflection under a certain load.

The role of the support bar

The height of the support bar plays a key role in both properties:

· The higher the support bar, the greater the strength (more load-bearing capacity)

· The higher the support bar, the greater the stiffness (less deflection)

This design choice therefore has a direct impact on both safety and user comfort. The correct dimensions not only determine whether the grating meets the required load requirements, but also whether it feels comfortable and stable in use.

How do we test strength and stiffness?

To guarantee the performance of our metal panels, we use practical tests with realistic load areas (such as 50x50 mm or 100x100 mm). We load the grating step by step and measure accurately:

· At what load does permanent deformation occur? (strength)

· How much deflection occurs under load? (stiffness)

We use this data to support our strength calculations and product selection, in accordance with the requirements of EUROCODE and the Dutch Building Decree.

Why this is important for your project

Whether you are working on an industrial installation or a public building, understanding the difference between strength and stiffness helps you make the right material choices. This prevents a grid from being strong enough but uncomfortable to the touch – or vice versa.

· Strength ensures safety.

· Stiffness ensures comfort.