Stone-coated steel roofing occurred during World War II when tar and sand were used to cover galvanized steel bunkers. After the war, the practice was commercialized and the first roofs were produced. Stone coated steel roofs have been protecting buildings for close to 50 years, but the product technology today bears little resemblance to early practices due to advances in the chemistry of coatings.
No. A properly vented steel roof system moves air both between the shingles and the underlying deck as well as moving air from vents under the decking. Heated air is allowed to dissipate through the ridgeline as cooler air is drawn through eave vents. Reduced energy bills can result from airflow both under and over the decking.
Yes. Some care must be exercised while walking on the roof, but note that roofers walk all over the shingles during the installation process.
The Metro roofing system is quiet. The combination of dead air space and the stone coating minimize outside sounds. One rural couple standing directly under a stone coated steel roof observed that they could hear the rain striking a metal building about 50 feet from where they were standing, but couldn’t hear any noise from the stone/steel roof directly over their heads.
The Metro roofing system has been proven to resist wind speeds in excess of 120-mph. One homeowner’s roof survived tornado force winds completely intact. "We lost 12 large trees…the shingled roof of our garage…a 14’ X 14’ (2" X 6") pump house deck slammed into the house and buckled the brick. You said it would hold up in a tornado. I’m writing to tell you it will." Bill Jamieson
Specially graded, non-oiled stone chips, produced by ISP Corporation, are used for all Metro stone-coated products. The finely graded, non-oiled stone granules ensure long-term adhesion to the steel substrate and are embedded in a UV resistant acrylic polymer for a lasting bond to the steel substrate.
The steel substrate is protected from corrosion by layers of metallic and polymer coatings. Metro utilizes an advanced metal composite developed by BIEC International and introduced in 1973 as aluminum-zinc coated steel. The composite improved earlier metallic coatings by applying an aluminum-zinc alloy to the steel in a continuous hot dip process. The aluminum creates an inert barrier coat while enhancing the long-term performance of zinc and its ability to protect breaks in the coating. Galvalume coated steel has repeatedly been shown in industry studies, conducted over the last 20 years, to outperform the corrosion resistance of other coated metals. This is why the Metro roof system is referred to as "The final Roofing System", and is backed up with a 50 year limited warranty.
Though sized more precisely, Metro uses the same stone granules used by asphalt shingle manufacturers for over 50 years, so history demonstrates that fading is not a problem. Over time, a slight change in color may occur due to settling of airborne contaminants, however periodic rain or washing the roof with a garden hose will keep the roof looking new.
Steel roofing is classified as a noncombustible roofing material (Class A). In new construction and in many re-roofing applications the metal roofing system is a Class A noncombustible roof assembly. In roof-over applications, where Metro panels are installed over old combustible shakes or shingles, the resulting roof assembly can be classified as A, B, or C depending upon the type of underlayment installed between the old and new roof. There are many examples of the safe fire performance of stone-coated steel roofs in areas subjected to fire storms. Additionally, the lightweight strength of the steel roofing system precludes it from crashing down on occupants exposed to fire within their residence.
Usually only a few days. The complexity of the building’s roofscape is the primary factor in determining the time required. Complex roofs require more time than basic designs.
PRODUCT WGT. PER SQ. (1-Sq. = 100 Sq.ft) Steel Roofing 125 lbs. Standard (3-Tab) Asphalt Shingles 190 — 215 lbs. Wood Shake/Shingle* 250 — 300 lbs.* Heavy Weight Laminated Asphalt Shingles 290 — 430 lbs. Clay / Concrete Tiles* 900 — 1200 lbs.* *Note that the weights for cedar, clay and concrete products are all dry weights. All three-product categories weights increase when wet.
Metro panels received the highest impact resistance rating from Underwriters Laboratories. Except under the most extreme storms, Metro panels show no visible effects from impacting hail stones. Some insurance carriers extend a discount on premiums to homeowners that have a Metro roof.
Steel roofing is no more susceptible to lightning than other roofing materials. It has been demonstrated that lightning strikes most frequently the highest points of terrain. Where concerns exist, lightning rods can be installed on roofs that are the highest point of surrounding terrain.