Layers beneath a roof covering and what each one does
The full roof build-up is determined not by a single material but by the arrangement of layers under the covering, which provide support, protection against water, reduced heat loss and moisture control. Before buying, establish the complete cross-section with the function of each layer and the detailing at the eaves, ridge and openings, rather than selecting materials separately. Check that the instructions permit their combined use and whether a layer correct under one product will suit every product. Remember that the membrane does not replace the vapour barrier, and the anti-condensation fleece is not insulation.









