When using PIR insulation panels in a flooring application what membranes are required?

Category: DIY

For installation on a concrete slab it is recommended that a damp proof membrane is installed below the insulation and then an additional vapour control / separating layer above the insulation before the screed / floating floor finish.
For suspended floor applications such as timber joists there should be the vapour control / separating layer included again before the finish of timber or screed.