Thermal conductivity (lambda value)
This is a measure of the rate at which a material will pass heat and is expressed in units of Watts per metre per degree of temperature difference (W/mK)

Impact sound
This is sound resulting in direct impact on a building element, such as foot traffic.

U-value
This is the measure of how much heat will pass through a square metre of a structure when the air temperature on either side differ by one degree. U-values are expressed in units of Watts per square metre per degree of temperature (W/m2K)

Airborne sound
This is sound that propagating through the air, often linked linked to noise sources such as music centres, televisions and speech.

Flanking transmission
This is sound transmitted between rooms via flanking elements instead of directly through separating elements or along any path other than the direct path.

Resilient layer
This is a a layer that isolates a floating layer, such as a chipboard from a floor base and surrounding wall.

Separating floor
This is a floor that separates apartments or rooms for residential purposes.