CPD: The Importance of Water Flow Reducing Layer in an Inverted Flat Roof

Ravago Building Solutions

This CPD article will discuss how a Water Flow Reducing Layer, such as Ravatherm XPS X MK, is central to the thermal performance of an inverted flat roof – minimising heat loss due to the rainwater cooling effect.

It explains the crucial role they play and how to properly account for their presence in U-value calculations. By the end of the CPD you should have a greater understanding of:

• Core principles of an inverted roof
• The difference between declared lambda and design lambda
• The role that a Water Flow Reducing Layer (WFRL) plays in an inverted roof
• How to perform a more accurate U-value calculation for an inverted roof taking into account moisture conversion factor