Metal Roofs

There are two primary types of metal commercial roofs—standing seam and r-panel. Standing seam roofs are typically chosen for their appearance and the way they are able to lock out water. The most significant feature of these roofs is the lack of visible screws that penetrate the metal unlike the r-panel roof. A high quality standing seam roof will have no screws visible on the entire roof. Therefore, there are no openings for water to enter the roof (other than penetrations such as vent pipes).

R-panel metal is widely used for both roofing and siding on commercial buildings of all sizes. It comes in many gauges or thicknesses. As a roofing material on a pitched commercial roof, r-panel is a very popular roofing choice due to the relative inexpensive price and durability.  One of the biggest disadvantages of r-panel roofing is that the screws penetrate the metal panel and are typically screwed into the perlins (or metal supports of the structure) as well. The screws have a rubber seal that is designed to prevent water from leaking where the screws go through the roof panels. As years go by the expansion and contraction that occurs during hot and cold cycles expands the screw hole. The rubber gaskets also deteriorate over the years due to UV rays. R-panel roofs are notorious for having many leaks after a number of years where the screws penetrate the panels. 

Another consideration of any metal roofing project should be how hail damage will be handled. Most commercial insurance policies include a rider that excludes cosmetic damage to metal roofs from hail damage. It is called a cosmetic waiver. If a metal roof with a cosmetic waiver is damaged by hail, this provision allows the company to deny coverage. This leaves a hail damaged roof that will slowly deteriorate due to the hail damage.