Green Roofing6 Main Causes of Shingle Roof Deterioration

January 8, 2018by BoldThemes0
Roofing company Vancouver

6 Main Causes of Shingle Roof Deterioration


It’s no surprise that asphalt shingles are the most popular residential roofing material. Not only are shingles economical, but they’re easy to install and conform to the traditional look of many neighborhoods.

While shingles are a great roofing choice, there are some common issues with this material that you may or may not experience during your roof’s life.

The best way to make sure a problem with your shingle roof doesn’t become a more serious and costly repair is to know about the potential issues that can occur. That way, you’ll be better equipped to notice a problem and ensure it’s addressed immediately.

For over 20 years, Sheffield Metals has been helping home and property owners choose the right roofing materials for their projects. While we deal mostly in the standing seam metal roofing market, we’ve come across many shingle roofs and the various issues that can happen, including some problems that have caused shingle roof owners to switch to metal.

So, before you make your purchasing decision, let’s go through the top six asphalt shingle roofing problems to look out for.

Shingle Problem #1: Blistering

One of the most common asphalt shingle issues that contractors are called out to fix is blistering. This happens when moisture trapped within the shingle expands and pops/breaks through the surface and creates an exposed spot. Most of the time, blistering occurs during the high-temperature summer months.

There are many origins for blistering. One of which is when moisture makes its way into the shingle during the manufacturing process. For a little bit of background, shingles typically consist of three main layers: A fiberglass backing, a coating of asphalt, and then the granules on the top. If moisture somehow makes its way between any of these layers, the potential for blistering is higher.

Another reason for blistering is poor ventilation of the roof that creates trapped moisture. Improper ventilation is the cause of many shingle roofing problems, so it’s critical to make sure the contractor is installing the shingles to allow for adequate ventilation and airflow.

Blistering exposes your roof, decking, and property to the elements, which can ultimately lead to leaking and premature failure of the roof system. That’s why it’s critical to address any blistering spots sooner rather than later. Additionally, blistering can sometimes resemble hail damage on your roof. Still, most contractors or roofing repair professionals can tell the difference and provide the best fitting solution.

Shingle Problem #2: Curling

The next common asphalt shingle roofing problem is curling. If you’re looking up at a shingle roof and see the edges of the shingle lifting off the roof’s surface or the corners turning upward, you’re seeing curling.

There are a several reasons that your shingles are curling, including:

  • The shingles are nearing the end of their useful lifecycle. Eventually, shingles will start to shrink up and curl, which is a sign that it might be time for a new roof.
  • The shingles were improperly installed. For example, misaligning the shingles during the installation or roofing over existing shingles that weren’t level (without a roof tear-off) could cause curling.
  • There are existing ventilation issues where trapped moisture has caused the shingles to curl.
  • One of the most popular reasons that shingles curl is due to a phenomenon called thermal shock. Thermal shock refers to when the high temperature of the roof suddenly cools rapidly. For example, if you have a warm day, the roof temperature will be higher because shingles absorb a lot of heat. Then, perhaps the weather quickly changes, cools down, and causes the roof to drop in temperature. This thermal shock can affect your shingle roof and start to create a curling effect as it happens over and over.

Like blistering, curling can lead to leaks and general roof failure if left unattended for a significant amount of time. Once you notice your shingles curling, it’s best to get that repaired or think about buying a new roof.

Shingle Problem #3: Cracking

The next issue you want to look for is any cracking taking place on the shingles’ surface. As you can see in the photo, cracking is pretty easy to spot on your roof’s visible areas.

Cracking is a natural part of the aging process for shingles. Over time, wind, roof stresses, thermal movement, and deck movement aid in a shingle cracking. So, if your roof is older and some surface cracks don’t completely split or tear through the shingles, it’s most likely because the shingles are older.

What you want to look out for is any premature cracking on a newer shingle roof. This could indicate that something happened during the installation, that there is a manufacturer defect that created a tainted product, or that there isn’t adequate ventilation for the roof system.

Again, cracking shingles are something you want to address immediately, as it can compromise the water-tightness of the roof if left unfixed.

Shingle Problem #4: Granule Loss
The next problem you might notice on your shingle roof is granule loss, which is where the top layer detaches from the shingle and falls off.

For a little bit of background, the granules added to the top layer of a shingle are finely crushed stones or ceramic that have pigment (organic and in-organic types) applied to them. In addition to the color that granules provide, it also creates a protective barrier to prolong the life of the shingle roof.

All shingle roofs will experience some level of granule loss over time due to weathering and exposure. However, if a large number of granules are in your gutter or specific spots of your roof are missing significant granules, it could be several causes, including:

  • The asphalt in the middle layer was not applied evenly or consistently throughout the shingle and has created an adhesion issue.
  • The roof overheated, melted the asphalt, and caused granule loss.
  • The roof is not properly ventilated, so there’s a problem in the property itself, the attic space, the insulation, or beyond.

If granules fall off at a high rate and the problem isn’t addressed, it can lead to clogged or blocked gutters, overall UV damage to the exposed shingle, leaking, or roof failure.

Shingle Problem #5: Mold, Mildew, & Algae
The next issues we’re going to cover are mold, mildew, and algae growth on or around your shingle roof. These occurrences are especially common in high-humidity areas and on northern-facing roofs (in the Northern Hemisphere) that are heavily shaded or rarely get sun.

Most of the time, the algae, mildew, and algae, which often looks like black streaks down a roof, are cosmetic issues that can be remedied. There are anti-algae shingles available for purchase if you’re concerned about organic substance growth. For example, GAF offers StainGuard Plus™ shingles contain copper and zinc metal ions that can help to reduce algae growth. You can also purchase solutions (i.e., Spray & Forget Super Concentrated Revolutionary Roof Cleaner) specifically designed to clean roofs with mold, mildew, or algae stains.

However, if the problem persists, these organic substances can cause the roof to trap moisture. Trapped moisture can wreak havoc on the roof underlayment and even rot out a plywood or OSB roof deck.

Shingle Problem #6: Missing Shingles
Since shingles are installed piece by piece, it’s possible for individual shingles to unattach and/or come off the roof.

This can happen for many reasons, including:

  • A strong wind lifted the edge of the shingle and disengaged it.
  • Something impacted or hit the roof and caused the shingle to disengage.
  • The sealing on the back of the shingle (black strip in the middle of the shingle) is broken/brittle.
  • The shingle was installed at too low of a temperature, and the seal couldn’t become engaged.
  • The seal was never properly engaged in the first place.

When a shingle comes off your roof, it’s best to get that repaired and replaced as soon as possible. Not fixing it can leave your home or business exposed to the elements for an extended period of time and create another problem on top of the missing shingle (think water damage).

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