GLOSSARY
Autohesively Bonded
Foam is bonded to the fibreboard through the manufacturing process by way of the liquid foam expanding and curing in the press.
Inverted Roof
The inverted roof is a construction by which the insulation boards are placed above the waterproof membrane.
Lambda or Thermal Conductivity value
Defines a materials ability to transmit heat. The Lambda is a given figure, there is a table of Lambda values in the building regulations part L.
Every material has its own Lambda value. The lower the figure the better the performance.
Unit of Measurement
W/mK
R-Value = Thermal Resistance
Defines a materials ability to resist heat flow. The higher the figure the better the performance.
Unit of Measurement
m2K/W
To calculate the R-Value:
Find the Lambda value (table in the building regulations, part L or on the packaging of the material).
Divide the thickness of said material in meters by the Lambda value.
Example:
100mm Polyflat
100mm / λ = 0.023
0.1 / 0.023 = 4.348
Thermal Resistance = 4.348
U-Value
Defines the ability of an element of a structure to transmit heat under steady state conditions. The lower the figure the better the performance.
Unit of Measurement
W/m2K
To calculate the U-Value:
Divide 1 by the R-Value
Example:
100mm Polyflat
1 / 4.348 = 0.22
U-Value = 0.22
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