Roofing Materials
No house is complete without a roof. If we didn't have them, we'd be awfully cold and wet in the spring and fall. The truth is, there are many types of roofs and choices. There are conventional shingles also known as asphalt shingles, metal roofs, which can be a combination of tin and steel. There are also flat roofs. Each has it's own unique qualities, but the chemistry behind all of the types of outer roofing materials differs drastically.
The different kinds of roofs. (Left) asphalt shingles. (Above) metal roofing (Right) Flat roofing.
Courtesy of JC Builders Inc. and their photographers and affiliates for sharing this image. 1/2/18
Courtesy of JC Builders Inc. and their photographers and affiliates for sharing this image. 1/2/18
Courtesy of JC Builders Inc. and their photographers and affiliates for sharing this image. 1/2/18
Asphalt Shingles
Asphalt Shingles, commonly known as shingles are perhaps the widely known type of roofing material. They too have evolved through the years. When shingle production began in factories, an ingredient added to the asphalt and paper was asbestos. Asbestos, Mg3Si2O5(OH)4, was used to strengthen the brittle shingles and prevent them from breaking while being installed. It also was thought to withstand the elements better. It turns out in 1989 the EPA banned the use of asbestos in all forms of building materials, the majority being shingles. Asbestos was discovered to be very harmful to the human body. It turns out Asbestos products, as they begin to age and break down, can create a powdery and fibrous dust. This dust can then become airborne and can be inhaled. Inhalation of the asbestos can occur without an individual being aware they have inhaled these fibers. Once the fibers are inhaled, they can incubate for several years until they cause serious and even deadly cancers. These include cancer of the stomach, intestines, and rectum, and a very deadly lung cancer called mesothelioma. Once they were banned asphalt and tar paper was the sole ingredient in these shingles. This is what we have on most of our homes today. The only form of wear and tear is the weather. Beneath the singles, there is a sublayer of tar paper that your roof is covered in. Then, you simply nail each single down to the roof. They are relatively cheap to install and last 20-25 years.
Metal Roofing
Metal roofing, also referred to as corrugated steel and tin, is one of the new types of roofing that is emerging. It is called corrugated roofing because roofing panels are punched out in a factory and delivered on the job site. It was originally designed as a cheap and effective way to cover small sheds and non-residential buildings. This was made out of galvanized tin. Galvanizing is an exothermic reaction of coating the material with zinc. By adding zinc, you will resist virtually every kind of weather. Zinc can't rust, which allowed steel roofing to come out. Steel roofing has been used to roof houses and commercial buildings now. You don't just see gray steel attached to a roof though; these corrugated panels are coated with a protective, UV-resistant paint. This paint protects the panels from the sun as well as a rust barrier in case the galvanizing ever happens to be worn off. Corrugation also helps these panels. By bending the metallic bonds in the roofing panel, there is less room for vibration, which gives the panel it's strength not to bend as well as defend against hail. This is considered the most effective type of roofing. They are supposed to last for 50-60 years; ho, ever it comes at a cost. These roofs are more expensive, but eventually, reach an equilibrium as they are the same price as shingles in the long run.
Flat Roofing
Have you ever seen a building with a flat roof? Many commercial buildings have them such as Fleet Farm, or schools. For example, our office and gym have them. These are designed to cut down on materials; however, still hold out water. These roofs actually aren't flat, they have a pitch (slope) of about 1/2 to 1/4 inch per foot. This is just enough for water to run off the roof. There are two methods for these types of roof. The first is a form of tar paper. In this, a paper (often consisting of tar) is laid down on the roof. It is then exposed to heat and undergoes an endothermic reaction. Heat is the catalyst for this reaction. As the paper warms up, it begins to melt at the seams and form a watertight seal. The roof becomes like a sheet of rubber or tar in a sense, and essentially every drop of water will stay out. The second method is relatively messy. Workers melt tar, which undergoes an endothermic reaction when heated (heat being the catalyst). The liquid tar is then dumped on the roof and spread evenly by workers. As the tar hardens, it seals the roof. This process is then performed a second and sometimes a third time to adequately seal the roof. Each undergoes an endothermic process and the price is about the same.
Sustainability
It is no question, you want your roof to last. This is the most important part of the house. If you can't keep the water off of your head, what's the point of a house? The good news is that every roof is sustainable. Flat Roofing is the least sustainable; however, it's lifespan is an amazing 15-20 years. It still needs proper maintenance, such as patching from time to time where some of the roof could be chipped. Flat relatively relativly expensive in a small area; but applied in a large area, it is chepar than every other type of roof. For a garage, this is not a good choice. Asphalt shingles are next. They have a lifespan of about 20-25 years. They will become brittle from the elements and soon start to break up. This is one of the most common types of roofing, merely because of it's cost as well as the beauty it creates on roofs. The most sustainable roof is the corrugated steel roofing, commonly referred to as a metal roof. With its ability to resist the suns' UV rays, it lasts up to 60 years. This roof is expensive; however, it is cheaper than re-shingling your roof every 20 years.