Considering a second layer of shingles for your home’s roof? This common question often arises when facing roof repairs or replacements. Adding another layer can be cost-effective and quicker, but it also has its drawbacks. Potential benefits include reduced labor costs and less mess. However, it may lead to increased weight on your roof structure and potentially hide underlying issues. In this article, we delve into the pros and cons of installing a second layer of shingles, helping you make an informed decision for your home. Read on to discover if this option suits your roofing needs.
Why It Could Be A Good Idea To Roof Over Existing Shingles
Despite several disadvantages of adding a second layer of shingles, some homeowners find a few key advantages. The primary benefit, though modest, is cost savings. Below, we outline the pros and cons of installing a second layer of shingles. Having this knowledge will enable you to choose your roof wisely. We delve into both the advantages and the potential drawbacks. By understanding these aspects, you can decide if this option suits your roofing needs. Keep reading to discover more about the benefits and disadvantages of a second shingle layer.
Lower Cost For The Homeowner
Installing a roof overlay can save you up to 25% compared to a complete tear-off. This considerable cost savings is the result of multiple causes. Since the original layer remains, waste is minimal. The only waste generated comes from new shingle cut-offs, ridge caps, and minor scraps, leading to low dump fees. Additionally, you save on labor costs related to tearing off the old roof. There is no need for extensive cleanup of shingles from the ground. Overall, opting for a roof overlay can be a more economical and efficient choice for homeowners.
The Convenience Factor
In an ideal situation, leaving the old shingles in place benefits both the contractor and the customer. The roofing contractor faces minimal cleanup and avoids the need for a tear-off. For the customer, this approach reduces the risk of damage to landscaping and flowers. Additionally, it minimizes hazards around the house from roofing debris. This method streamlines the process, making it quicker and more efficient for everyone involved. By preserving the existing shingles, the project becomes less invasive and more convenient. This approach ensures a smooth and effective roofing experience.
The Time Factor
Skipping the tear-off process speeds up the installation. If your roof has no leaks and needs no repairs, the job finishes quickly. The roofing contractor also bypasses underlayment installation, which saves time and reduces costs. This method is both efficient and cost-effective, offering a quicker solution without compromising quality. Always ensure your current roof is in good condition before choosing this option. Consult with a professional to determine the best approach for your roofing needs.
Why Is It A Poor Idea To Put A Second Layer Of Shingles?
While adding a second layer of shingles offers some initial benefits, the disadvantages quickly outweigh them. Consider the drawbacks before proceeding. Here are 14 reasons you might rethink installing a second layer of shingles on your roof.
Void On Manufacturer’s Warranty
Most roof shingle manufacturers will void any warranty if shingles are applied over an existing layer. If they do warranty a second shingle layer, it’s only if a certified roofing contractor does the installation according to their specs. Often, it’s easier to tear off the old layer than to install a new one following the manufacturer’s specs. Reading the fine print of the shingle warranty will reveal how easily it can be voided, even without applying shingles over another layer. Always check the warranty details for the specific shingles you plan to install.
Does Not Remove Ice Dams
If you’ve had ice damming or roof leaks, adding another layer of shingles might not fix the issue. Ice damming usually happens near the eaves, where cold outside air meets warm air from your attic or walls. Rapid freezing and thawing cause ice to form under the shingles, leading to leaks when it melts. The solution is proper insulation in your attic to prevent warm air from entering. Additionally, installing an ice and water membrane under the shingles is crucial. This combination helps eliminate leaks and protects your roof from future damage. Act now to secure your roof’s integrity.
Adding another layer of shingles does not address underlying underlayment issues, which can lead to recurring problems. Ice damming and leaks may persist even after the new layer is installed. These issues will return when winter conditions favor ice damming. It’s essential to fix the root cause, not just add another layer. Addressing underlayment problems and ensuring proper insulation can help prevent these issues. Consult a professional to evaluate your roof’s condition before deciding. This approach ensures a long-term solution, avoiding repeated ice damming and leaks during winter. Take action now for a more effective roofing solution.
Reduced Shingle Survival
Adding more shingles to your roof creates an extra heat-absorbing layer during summer. This added heat can shorten the lifespan of the shingles, causing warping, blistering, and granule shedding. Over time, the new shingles will conform to the shape of the layer beneath. If the new shingles are thicker, this might be less noticeable. However, trapped moisture between the layers can break down the shingles. This moisture can seep through, leading to deck rot and mold growth. Often, the lifespan of the second layer of shingles is significantly reduced, sometimes even halved.
Code Might Not Permit It
Most townships permit a second roof layer, but some do not. The added weight from extra shingles and snow can stress roof rafters. Especially in newer homes, contractors often use the most cost-effective framing options. These rafters are not designed to handle such weight. Therefore, before adding a second layer of shingles, check local regulations and consider the structural capacity of your roof. Consulting a professional can help ensure safety and compliance with local building codes.
An Actual Pile Of Extra Weight!
If an average bundle of architectural shingles weighs between 65 and 80 pounds, a typical roof size of 20 squares (2,000 sq. ft.) will add 3,900 to 4,800 pounds with a second layer of shingles. This extra weight puts significant stress on the house’s framing. Before adding a second layer, consider the potential impact on your home’s structure. Always consult a roofing professional to assess if your roof can handle the additional load safely.
The Factor Of Heat
Shingles still absorb heat, even though lighter shingles typically absorb less heat from the sun than darker shingles. One of the primary materials of a shingle, asphalt, will constantly absorb heat. The temperature at which the shingles on the roof can get is understandable if you have ever experienced a hot summer day while walking barefoot on an asphalt driveway. By adding a second layer, you now have two layers that are constantly absorbing heat. That heat absorption will cause both layers of the shingles to deteriorate more rapidly than it would if installed as one layer over roof decking.
Trapped Moisture On The Roof
Trapped moisture between shingle layers can damage the roof decking, insulation, and shingles. Adding a new shingle layer over old ones won’t prevent the old layer from deteriorating further. As moisture penetrates the decking, expect it to rot and decay. Wet insulation in the attic cavity can also lead to further damage. Even the roof trusses, which support the roof, can rot. It’s crucial to consider these risks before deciding to install a second layer of shingles. Ensure proper inspection and repair of the existing roof to avoid costly damage.
Additional Roof Preparation
Manufacturers design shingles to be installed on a flat surface for proper sealing and waterproofing. Roofs with 3-tab shingles remain relatively flat due to their non-dimensional design. However, roofs with architectural shingles require thicker new shingles. The first course of new shingles must be rip-cut to fit properly. Despite the new layer, imperfections in the original layer, such as blistering, dips, and gaps, will eventually show. This happens as the top layer seals and conforms to the older shingles’ shape. It’s crucial to consider these factors before deciding to add new shingles over existing ones.
Roof & Shingle Repairs Still Necessary
Replacing or repairing roof vents, pipe boots, and flashing is crucial for proper waterproofing. Ignoring these tasks will almost certainly lead to leaks. Ensure any needed repairs to the original layer of shingles are completed before adding a second layer. Neglecting these steps compromises the integrity of your roof. Always address these essential repairs to maintain a leak-free, durable roof. Proper maintenance and repair are key to extending your roof’s lifespan and avoiding costly damage. Take action now to secure your roof’s durability and efficiency.
Shingle repairs are necessary, often posing a challenge. The price difference between a full roof replacement and adding shingles is usually small. If extensive repairs are needed or unexpected damage occurs during installation, homeowners and roofing contractors face two choices.
If the necessary repairs are done, the cost may equal or exceed a complete tear-off. Avoiding repairs dramatically shortens the new roof’s lifespan and can cause leaks. Ultimately, the customer pays either upfront or later when leaks occur. A roof-over without proper workmanship might not include a warranty, leaving homeowners with repair costs again. To ensure your roof’s longevity and avoid unexpected expenses, consider the full cost of necessary repairs. Investing in quality work now can save you money and headaches in the future. Make wise choices to safeguard your finances and house.
Roof Decking And Underlayment Cannot Be Replaced
As technology advances, synthetic materials are replacing felt paper as water barriers in roofing underlayments. Ice and water membranes are now standard in colder climate roof installations. Ice buildup can occur near eaves and in valleys during cold winter months. Most older roofs still have regular felt paper due to this being relatively new technology. Upgrading to synthetic underlayments can provide better protection against moisture and ice. Consult a roofing professional to assess your roof’s current underlayment and consider an upgrade for enhanced durability. Ensure your roof is equipped with the latest advancements for optimal performance.
Curb Appeal
If the original shingles are architectural, the new layer will mimic their shape. Blistering, curling, or dips in the old shingles will likely show through the new layer. Any imperfections in the original shingles will appear on the surface. Additionally, dips or lifted areas in the plywood will be visible even with a new layer of shingles installed. This means underlying issues can affect the look and performance of the new shingles. It’s crucial to inspect the existing roof thoroughly before adding a new layer. This ensures the new layer will function and look as expected.
Home Resale Value
If you plan to sell your home, a second layer of shingles will appear on the inspection report. Potential buyers will use this as leverage to negotiate a lower price or demand a roof replacement. The initial savings from avoiding a tear-off will be outweighed by the cost of replacing a roof with two layers. Additionally, insurance companies are becoming stricter about multiple roof layers. They may only insure one layer or refuse to issue a policy if there are two. Two layers of shingles pose a higher liability for insurance providers.
Future Roof Repairs
If the roof leaks, fixing two layers of shingles can be a nightmare. Pinpointing a leak on a single layer is challenging because water travels along beams, rafters, and roof decking. Repairing two layers requires significant labor to do the job properly. After removing both layers to perform necessary repairs, you need to reinstall both layers. Installing only one layer will create a dip in the roof where repairs were made. This dip can lead to sitting water in the repaired area, causing unwanted leaks. Therefore, repairing two layers of shingles is complex and labor-intensive.
The Liability Factor
You might think leaving the original roof shingles in place reduces liability, but that’s not necessarily true. Keeping the old layer creates more liability for homeowners. Future roof replacements will be costly. Repairing potential leaks will also be expensive. The added weight on the roof is a liability. You risk losing insurance coverage. Additionally, your home’s resale value may drop if you plan to sell. For roofing contractors, installing a second layer without removing the first adds liability. If the roof leaks, fixing it will require extensive and expensive labor. This increases risks from a workmanship perspective.
Conclusion:
After exploring the pros and cons, it’s clear that adding a second layer of shingles has both advantages and disadvantages. While it can save money and time, it also introduces potential risks such as increased weight, hidden issues, and reduced insurance coverage. Making an informed selection requires having a thorough understanding of these factors. Consult with a roofing professional to evaluate your roof’s current condition and determine the best approach. Ultimately, weighing the benefits against the drawbacks will help you decide if installing a second layer of shingles is the right choice for your home.
