How to construct Metal Perimeter Roof Flashings to ensure long term performance?

Metal perimeter roof flashings and details are one of the least considered aspects of any metal roofing & cladding system and yet in most cases these details are not guaranteed either by the supplier or the installer for performance but just the life of the material itself.

Metal roof sheeting, if installed correctly, rarely leaks and yet the areas where water ingress is a typical concern is the metal roof perimeter details such as ridges, barges, change in angle or penetrations. These perimeter metal roof flashings are generally left to the installer to design and in most cases are constructed on the ‘industry standard’ 462mm girth as you can form two metal roof flashings from a flat sheet, however there is little technical merit in the size of metal roof flashings.

Please see below a technical overview of what size these roof flashings should be to ensure long term performance.

Please Note: The impact of water ingress into a building will invalid any thermal, acoustic or fire performance of any insulation blanket guarantee.

As one of the only specifiers, installer and maintainers of metal roofing and cladding systems, who provides a system warranty that includes materials, workmanship and maintenance for up to 20 years, we believe it is essential to provide technical information of how these perimeter roof flashings should be constructed to achieve the guaranteed length of term.