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The Truth About Double Layering Shingles: A Roofer’s Perspective

When it comes to roofing, double layering shingles (installing a second layer of roofing material over an existing layer on a roof) may seem like a time and money-saving solution. However, while it may seem like a good idea, it’s important to understand why double layering shingles is not recommended. Today we are going to explain why multiple layers of shingles is not the best plan, and what you should consider instead.

up close picture of a roof with double layering shingles

Decreased Lifespan of Your New Shingles

One of the most significant drawbacks to double layering shingles is that it can decrease the lifespan of your new shingles. Shingles are designed to lie flat and uniform. However, when double layering it immediately sets your new shingles on an uneven surface. In turn, this can impact their ability to last. Additionally, the existing shingles underneath will retain heat, which can cause your new shingles to overheat and age faster.

This Can Also Cause Missing or Curling Issues

The additional weight and heat from the new layer can cause the underlying shingles to deteriorate faster, resulting in them becoming loose or curling up. This not only compromises the structural integrity of the roof but also increases the risk of leaks and water damage.

Decreased Property Value

Many homeowners often go this route as it is more of a cost-effective solution for them. However, this approach can lead to a lumpy or uneven appearance, which can significantly affect the aesthetics of your roof. The additional layer can cause the roof to appear bulky and unprofessional, detracting from the overall visual appeal of your home or property. It is important to consider the negative impact that double layering can have on the appearance of your roof before making this decision.

What’s even worse, the impact of double layering goes beyond just the visual aspect. It can also affect the value of your property in the long run. More often than not, home buyers shy away from homes with multiple layers of shingles. When it comes time to sell your home, potential buyers may see the double layering as a sign of poor maintenance or improper installation, which can lower the perceived value of your property. It’s important to remember that the roof is a vital component of a home and can significantly impact a property’s overall value.

Increased Weight Strain on Your Roof

Another significant drawback of roofing over existing shingles is that it adds extra weight to your roof. A typical bundle of roofing shingles can weigh between 50 and 80 pounds. This is equivalent of up to 3 pounds per square foot, and each additional layer of shingles can add anywhere from 2 to 4 pounds per square foot. This additional weight can put undue strain on your roof and, in some cases, can lead to structural damage.

Affects Manufacturer’s Warranty

Double layering shingles can void the manufacturer’s warranty on your roofing materials. As said before, shingles are designed to be installed on a flat surface. Some manufacturers will stipulate this as part of the installation instructions. If your new roof deviates from these instructions, the manufacturer may not cover the product under their warranty. It is important to know this before your new shingles are installed.

Owens Corning Standard Product Limited Warranty

When purchasing a product, it’s important to understand the warranty that comes with it. In the case of Owens Corning’s standard product warranty, there are certain aspects that are not covered. Are you aware of what these exclusions are? Knowing the warranty limitations can help you make informed decisions and avoid potential disappointments down the line. As seen below, the Owens Corning Standard Product Warranty does not include a roof with double layering:

“Roof damage or leaks caused by pre-existing conditions, underlying roofing materials, underlying structural failures, settlement, or any defective areas on or near the roof that are not part of the Roofing System. Examples include but are not limited to chimneys with loose or cracked mortar, damaged siding, faulty counterflashing, or improperly designed or installed gutter or downspout systems.” (Owens Corning Standard Product Limited Warranty, page 3).

Owens Corning is a reputable company known for its high-quality products, including roofing materials, insulation, and fiberglass composites. Their standard product warranty provides customers with peace of mind, but it’s crucial to be aware of the limitations it entails.

While the Owens Corning standard product warranty offers protection for their products, understanding the warranty coverage is equally important. By familiarizing yourself with these exclusions, you can manage your expectations and ensure that you are making the most of your purchase.

More Difficult to Determine the Root Cause

When you double layer shingles on your roof, it can create a barrier. This makes it challenging for roofing contractors in Arlington Heights to properly identify and address any underlying problems. This is because the second layer of shingles covers up the first layer, making it difficult to visually inspect the condition of the roof beneath. Additionally, if there are any leaks or damage to the underlying roof, the second layer of shingles can mask these issues, prolonging the time it takes to detect and fix them. It is important to carefully consider the implications of double layering shingles and consult with a professional roofer to ensure the long-term health and durability of your roof.

More Difficult to Repair or Replace

Finally, roofing over existing shingles can make any necessary repairs or replacement more difficult and expensive. When it comes time to replace your roof, you’ll have to remove both layers of shingles, which can be a time-consuming and expensive process due to the added weight. Shingles are often textured, which can also make it more difficult to slide repair pieces in place.

What Does This Mean For You?

While double layering shingles may seem like a good idea, it’s important to consider the potential drawbacks. A new roof is a significant investment in your property, and it’s essential to do it right the first time. Consult with a Arlington Heights roofing professional, like Davis Roofing & Construction, to ensure that you make the best decision for your property and budget. Once you meet with us, we can help you understand the best path forward.

The Key To A Long Lasting Roof

We believe in offering roofing solutions that prioritize durability and longevity. By providing a thorough inspection and assessment of your roof, we can identify any underlying issues and provide appropriate solutions. Whether it’s repairing damaged areas, replacing old shingles, or even considering a complete roof replacement, we are committed to delivering the highest quality results that will ensure your roof’s longevity and protection for years to come.

To learn more, contact Davis Roofing & Construction today at 630-948-5000