Metal flashings are fabricated from a variety of metals and alloys: Galvanized Steel, Galvalume, Zinc, Copper. The coatings used to provide rust protection include baked enamel, silicon, and kevlar among some.
Steel, Galvalume and zinc come in a variety of thicknesses: 32G, 30G, 28G, 26G and 24G with the thickest being 22 Gauge and the weight of Copper ranges between 12 and 32 ounces.
The performance of a metal flashing is directly correlated to the type of metal or alloy incorporated, the thickness or weight of the material, and the protective coating applied.
To resist wind uplift forces, metal clips and concealed fasteners are used to secure the flashings to the building during the installation process.
The seams of metal flashings are not waterproof but rather water shedding. A waterproof membrane must be installed prior to the installation of metal flashings as apart of the metal flashing detail. To prevent leakage, metal flashings must be installed in a manner that will ensure water sheds away from the seams.
Metal flashing details are only one part of the buildings envelope and must be incorporated into the design of transitional details to ensure the building is protected from wind and rain.