‘Declared thermal conductivity’ is the lambda value of an insulation product as it leaves the factory. In the context of inverted roofing, ‘design thermal conductivity’ is the lambda value of the insulation once it has been adjusted for potential moisture absorption.
EXTRUDED POLYSTYRENE FOAM High performance thermal insulation for residential and industrial buildings
When calculating the U-value of an inverted flat roof, the thermal conductivity of the insulation layer should be the product’s design lambda value and not its declared value. Because of the insulation’s position above the roof waterproofing layer, it is expected to be exposed to some rainfall and therefore a moisture correction factor should be applied accordingly.
A water flow reducing layer (WFRL) is a loose laid membrane used as part of inverted flat roof constructions. It is installed over the roof’s thermal insulation layer, and below the roof covering. A WFRL is a barrier to rainwater, reducing the volume of water that can reach the waterproofed roof deck. It also stops fines from entering the roof system.
High compressive strength thermal insulation for inverted, green and blue roofs.
Very high compressive strength thermal insulation for high load inverted roofs and car park decks.
High compressive strength thermal insulation for residential buildings.
High compressive strength thermal insulation for residential and industrial buildings.