Protecting the underside of your metal roof or cladding will ensure a longer roof life. Metal roofs and cladding are not sealed to the roof deck or sheathing, which allows moisture to easily get underneath the metal.
If moisture is allowed to accumulate, two problems can arise. The first is premature damage to the roof substructure, requiring removal of the metal and repair. The second is condensation on the underside of the metal – which can lead to corrosion and require the metal to be replaced sooner than necessary.