Vapor barrier between insulation screed and OSB: When is it necessary?

Find out when a vapor barrier between insulation screed and OSB is needed. Prevent moisture problems and ensure correct installation of your floor insulation.

Is it necessary to install a vapor barrier (foil) between the insulation screed and the OSB, and under what circumstances is this necessary?

As standard, placing a vapor barrier between the insulation screed and the OSB is not necessary. It is only necessary if you know in advance that moisture may come out of the substrate in the coming months or years. If no moisture problems are expected, you don't need to worry about adding a vapor barrier.

Do you have any more questions about the installation of insulation screed, OSB or the use of a vapor barrier? Please visit our FAQ page for more information and detailed instructions.