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Everything you should (but probably don’t) know about asphalt shingle roofs.

Composition of asphalt shingles

When you picture a roof in your mind you’re probably picturing an asphalt shingle roof of some kind. That is the go to roofing system for almost every roofing contractor and home-owner alike. Whether it’s an architectural roof shingle, three tab, or a fancy designer roof shingle, a new asphalt shingle roof can protect your biggest investment, add value to your home and give you serious peace of mind. But have you ever wondered what the heck an asphalt shingle even is? Here’s a brief overview of what makes up a standard asphalt shingle and why they are made that way! Every asphalt shingle has 3 basic components: Mat, Asphalt, and Granules.

The foundation of an asphalt shingle

The Mat is the foundation of the asphalt shingle. Typically the mat is made of fiberglass and is the backbone of the roof shingle. This mat consists of long fiberglass strands bound together to form large sheets of strong, flexible, and itchy (seriously, don’t play with this stuff too much) matting. There have been a few attempts to make “organic” mats, using recycled plant matter, but these all failed prematurely and were taken off the market. Please don’t ever install “organic shingles” on your home, they literally will rot on your roof. Fiberglass, on the other hand, is completely corrosion free, lightweight and remarkably durable and makes the perfect foundation for roof shingles. The purpose of the mat is to provide a structure for the waterproof stuff to adhere too. Speaking of waterproof stuff.

Asphalt is key to making your roof waterproof

Asphalt Roof shingle manufacturers use a specialized formulation of asphalt (which itself is just a super viscous form or petroleum) to coat the fiberglass mat. The long strands of porous fiberglass have a ton of surface area, making the asphalt bond and hold tight to the structure of the mat. The result is a completely waterproof sheet that can hold its shape, withstand huge temperature gradients and rapid temperature changes without cracking, deforming or leaking. At this point your roofing contractor could slap this on top of your house and it would keep you dry for a bit. The problem is that asphalt is pretty reactive to UV light. When exposed to sunlight, asphalt degrades and starts to shed the oils that are held in the bitumen. It cracks, becomes brittle and ultimately just crumbles, leaving stinky, oily residue on your roof decking. What you need is some kind of non-reactive, hyper-durable coating to protect the asphalt from the damaging rays of the sun. That’s where the third element comes in.

Stone granules protect your asphalt shingle

Granules are usually made of ground up rock particles and covered in silicate (more or less glass). These small particles are stuck to the outside of the molten asphalt shingle during manufacturing, and their primary function is to shield the waterproof asphalt from UV light. This is why granule loss by itself can be a reason to replace your asphalt shingle roof, and the main way that hail can damage asphalt shingles. The granules are also the only coloring agent in asphalt shingles. So if you see a red roof shingle out there it is likely literally coated with some kind of rock that has high iron content. Interestingly much of the stone coating on asphalt shingles is literally just mined rock of various colors. If you have a black roof shingle it’s very likely that your home is covered in literal volcanic rock. Although there are some synthetic granules out there, they are not the industry standard and don’t really have any performance benefits over natural rock.

The best roofing system for your home?

Those three components are the foundation of every asphalt shingle. Some asphalt shingles will have multiple overlapping layers of asphalt and mat that give the shingle higher wind and impact resistance, these are called architectural shingles. Others have additional structural elements built into the nailing run to both reduce installer error and reinforce the nailing points. There are also some coatings that can be applied to the granules that increase the reflectivity of a roof shingle and can contribute to a cool roofing system. Although the look, longevity, and durability of roofing shingles can vary dramatically from product to product, they are all essentially variations on the theme of mat, asphalt, and granules. If you’re thinking of replacing your roof, a new asphalt shingle roof may well be the best choice for you.

Trust a roofing contractor to help you

Once you’ve met with your roofing contractor and decided that an asphalt shingle roofing system is right for you there are still a few varieties of roofing shingles that are available. The basic and most common roofing shingle is what is commonly referred to as a 3-tab. This roof shingle consists of a single layer of fiberglass, asphalt and granules. This is currently the most common type of roofing shingle and is often used in new “builder grad” construction. We can get it, but as far as roofing shingles are concerned, it’s not the best.

Your roofing contractor will likely recommend and upgrade to what is referred to as “architectural shingles” or “dimensional shingles” These roof shingles have multiple layers of matt and asphalt, which increases their impact resistance and their ability to tolerate high winds. These two types of roof shingles have dramatically different performance. Just as an example a standard 3-tab asphalt shingle typically has a wind rating of 60 MPH. The HDZ roofing shingle has a wind rating of 130 MPH. It’s always good to discuss any large project with a roofing contractor, but generally speaking an architectural shingle is a much better product and arguably one of the best roofing materials on the market.