Stone-coated metal roofing is made from steel sheets, and then coated with stone granules.
The steel sheets make the perfect substrate since they can easily be “stamped” into a wide variety of shapes. The stone-coating process allows for a wide variety of vivid colors and textures that can replicate the look of traditional roofing materials like asphalt shingles, clay tiles and wood shakes. This is what gives stone-coated metal roofing products, such as DECRA Metal Roofing, the design versatility to suit any style.
For example, the aesthetic versatility of DECRA stone-coated metal roofing products can replicate the cultural and historical integrity of traditional roofing designs, including:
Cultural integrity of the Polynesian Cultural Center in Laie, Oahu, Hawaii.
Historic restoration and preservation for the Hearthstone Historic House.
stone-coated metal roofing products are ideal for upscale designs as well, including:
High-end condominium project in Ottawa, Canada.
Resort architecture in North Carolina.
It’s important to note that the stone granules in stone-coated metal roofing products provide much more than design versatility. In addition to the long list of benefits that metal roofing provides, stone-coated metal roofing comes with its own additional benefits as well, including:
Enhanced Energy Efficiency: Infrared pigments embedded in the stone-coatings increase the natural solar reflectance (aka energy efficiency) of a metal roof. Learn how in this recent U.S. Department of Energy Study that verifies the thermal performance ofstone-coated metal roofing products.
Noise Reduction: stone-coated steel roofing profiles don’t require any extra soundproofing materials and are peacefully quiet in the rain thanks to the sound-absorbing cushion of granular stone coating. Learn more about how quiet DECRA roofs are in our blog, Are Metal Roofs Noisy in the Rain?
Let’s dive deeper into what exactly the stone granules in stone-coated metal roofing are made of.
The Stone-Coated Metal Roofing Manufacturing Process
The stones in DECRA’s stone-coated metal roofing products are called roofing granules. The granules are manufactured from natural stone which was mined at a quarry, then crushed and screened to various sizes. The granules are manufactured in such a way that when applied to and embedded in our acrylic base coat, the particles fit together to provide the maximum coverage for our roof panel surface.
Several characteristics are critical when analyzing and selecting an appropriate and suitable stone, including:
Hardness
Opacity to solar ultraviolet light
Chemical and physical inertness to provide resistance to acid rain and leaching
Durability to freeze/thaw and wet/dry cycling
Minimal oxidation and rusting (iron content)
Low porosity
Suitability for coating
Particle shape
The granules achieve their vivid colors through a process where the stone particles are coated with a combination of pigments similar to paint. The pigment slurry mixture, once applied to the stone, is baked on at high temperatures causing the pigment mixture to coat the stone in a ceramic process. Pigment selection will determine the final appearance and color of the roofing granule.
Multiple color readings, using a spectrophotometer, are performed at different intervals during the manufacturing process.
Color fixation tests are also conducted to make certain that the pigmentation has adhered properly to the stone granule – ensuring that the color will remain stable over time. Given the intense solar UV exposure on a roof system, roofing granules must prove to be durable. utilizes state-of-the-art computerized roofing granule blending and application machinery to ensure a quality stone coat manufacturing process.
