An increasing number of property owners are opting for various types of skylights, including tube lights and roof windows, in their buildings.
Due to the critical nature of proper flashing for these items, the metal roofing contractor/installer should be involved. There are three things that differentiate metal roofing from other products when it is installed with skylights. One, care must be taken to separate dissimilar metals. Two, although sealants will be used, they should not be heavily depended upon for watertightness as they will not last the life of the metal roof in most cases. And, three, the high profile of most metal roofs must be taken into consideration with the flashing design.
Metal roofing manufacturers are always glad to be consulted when determining proper flashing methods and designs. Most tube lights include flashing packages that work very well, particularly with horizontally-run metal roofs, and can be installed similar to pipe flashings. When installing skylights and roof windows, it is critical for them to be “curb-mounted” rather than flush-mounted. This means that they must sit up above the roof an adequate amount so that they still extend a few inches above the highest part of the metal roofing profile. Most quality skylights and roof windows come with flashing packages that can be incorporated into the overall flashing with the metal roofing. Dissimilar metals should be separated by building felt or a rubberized material. Property owners should be aware that noise from heavy rain hitting skylights can be quite loud and they should not confuse this with noise from rain hitting the metal roof.