FAQs - Subject: Questions about floor substrates

What do we mean by footfall noise?
This term includes all sounds generated by mechanical agitation of the floor, which are transmitted to neighbouring rooms and rooms underneath.
What do we mean by mechanical agitation?
Running, playing, work activities, falling items, etc.
What is footfall noise insulation? (according to DIN EN ISO 140-8)
It means reducing the transmission of impact noise into neighbouring rooms.
What do we mean by impact noise?
Noise travelling in solid materials.
What is footfall or room sound? (according to IHD 413 or EPLF)
It characterises the noise event perceived by walking on a floor in the occupied room.
What is dynamic stiffness? (according to DIN EN 29052-1)
This defines the resilience of the substrate including the small air bubbles incorporated in the materials.
What is heat transfer resistance? (according to DIN EN ISO 12667)
It represents the resistance of a component to the transmission of heat.
What is the water vapour diffusion resistance? (according to DIN EN 12086)
This is the resistance of a material to diffusing water vapour.
What is diffusion?
It is the mingling of two substances to balance out differences in concentrations.
What do we mean by the Sd-value?
The Sd value indicates the diffusion-equivalent air layer thickness.
For example: a material with an Sd value of 150 m offers the same resistance (against penetration) to a water molecule as a layer of air 150 m thick.

Ranges of Sd values:

Sd ≤ 0.5 m => diffusion-open
0.5 m diffusion-proof

What do we mean by pressure stability? (according to ISO 844)
This refers to the resistance of a material to a load per surface. Where the load exceeds the resistance, the structure of the material is destroyed.