A metal roof, also referred to as a tinroof, is a roofing system made from metal sheets or tiles. They come in a variety of colors and configurations and has been used in various forms for many years. Corrugated galvanized steel roofs helped forge American building as a cheaper alternative to wood. Lightweight, portable, and a strong barrier against the elements made a popular building component. Today, with a drive towards eco-friendly green building alternatives, metal roofs are again a popular choice.
What are Metal Roofs Made of?
The main material used is steel. For corrugated galvanized steel roofs, a wrought iron-steel sheet is coated with zinc. A blend of zinc, aluminium and silicon-coated steel is often used for factory coated colored roofs, while stainless steel is the choice material in harsh weather conditions. However, aluminium and copper are also popular metal materials for roofing. Aluminium is lightweight and extremely long lasting, making it a popular material. Copper is more often used for flashing (metal placed around protruding structures on roofs such as chimneys to prevent leakage into seams) as it is an extremely expensive material. However, the beauty of copper makes it sought out, especially when restoring historical buildings. The industry has turned away from use of lead due to the negative health and environmental implications of the material
Metals roofs, being lightweight, make them easy to transport. However, they are also extremely durable as the oxidization of the base material forms a protective patina. The lowest end metal roofing can last 20 to 30 years, which is roughly twice the lifespan of an average asphalt roof. Likewise, coatings used can be designed for the particular environmental elements, making the materials that much tougher to resist wear and tear. They are generally fire and spark resistant, and stand up to wind, hail as well as cause what is known as “snow shedding.” Simply put, once the metal roof warms up a few degrees higher than the snow, the snow loosens and slides off.
As eco-friendly material, metal roofs are used in what is known as “Cool Roofing.” The urban heat island effect is the absorption of heat in urban areas which adds to global warming. They reflect the heat, aiding in reducing atmospheric temperatures. With lower levels of absorbed heat, the structures themselves maintain cooler temperatures, reducing the need for air conditioning in the hottest months. Because of these green benefits, many buildings with metal roofs qualify for LEED (Leadership in Energy Efficient Design) tax credits. Likewise, metal materials used on roofs can be recycled.
Another advantage is the material can easily cover large buildings with less material than other types of roofing, and repairs and maintenance are considerably less in both price and occurrence. And although metal roofing can be expensive, the pricing has become considerably more affordable as oil prices (affecting asphalt roofing) rise.
Some disadvantages to metal roofs are care must be taken to provide thermal expansion and movement or else damage in the form of cracks and leaks may occur. Related to this, the expanding and contracting in extreme temperatures often causes objectionable noises. Dissimilar metals, when exposed to each other, will negatively affect one another, causing corrosion. This makes proper installation and repair vital. And if not coated properly, over time the weather elements can rust or weaken the seams. Likewise, proper maintenance requires recoating. How often will be determined by the coating materials used.
To learn more about whether metal roofing is the right choice for your needs, contact a metal roofing specialist in your area.