European end lap systems for insulated roofing rely on sealant which can be often compromised during installation and from expansion/contraction post-install. This can lead to serious issues with water ingress into buildings and especially in Australia’s harsh climate corrosion of end lapped sheets due to condensation & movement, usually not covered by steel suppliers forcing costly replacement which raises issues by building owners as to who is i.e. designer, builder, installer or premisise owner.