Common Reasons Why Metal Roof Leaks and How to Prevent Them

Regular and proper maintenance is crucial for any type of roof, especially in Maryland’s diverse climate. This practice is essential for extending the lifespan of your roof. If you have a metal roof, it’s important to understand the reasons behind potential leaks and how they can occur. With over 20 years of roofing experience in Maryland, we’ve compiled a list of common reasons for metal roof leaks and the most effective approaches to address them.

1. Metal Roofing Screws

Metal roofing screws play a crucial role in preventing water penetration, as they create a seal between the roof panels and the structure. However, improper installation of these screws can lead to leaks. Here are some common mistakes associated with metal roofing screws:

• Improper Angle: Screws driven at the wrong angle can cause leaks. It’s essential for the screw to sit flat against the metal panel to ensure proper sealing.

• Over-Driven Screws: When screws are driven too far into the metal panel, they can break the rubber washer, compromising the seal. This happens due to the excessive surface tension applied by over-driven screws.

• Under-Driven Screws: If the screws are not driven enough to compress the rubber washer, the seal between the screws and the metal panel will be ineffective, leading to potential leaks.

• Wear and Tear: Even correctly installed screws can degrade over time due to natural wear and tear. As they deteriorate, they lose their ability to maintain a proper seal, increasing the risk of leaks.

• Missed Frame: Placing metal roofing screws incorrectly, such as not aligning them with the metal strut or wood framing, can render them ineffective. This not only makes it difficult to locate leaks but also undermines the integrity of the roof’s sealing system.

2. Missing Sealants

Certain areas of metal roofs require high-quality sealants to ensure waterproofing, and these sealants must retain flexibility to accommodate the natural expansion and contraction of roof panels. While these sealant-reliant areas provide essential protection, they are more vulnerable than the roofing panels themselves. Therefore, regular inspection and, when necessary, maintenance are crucial. Pay close attention to the following areas to identify potential damage:

• Metal Ridge Caps

• Counter Flashings

• Z-Flashings

• Roof Transitions

• Reglets

• Pitch Pans

3. Curb Flashings

When installing HVAC units on a metal roof, they’re typically mounted onto a roof curb—a metal structure designed to support the system’s weight and connect it to the ductwork. Despite having properly installed curb flashing, water can still seep through the roof around the area of the roof curb. Unfortunately, rectifying this issue often proves challenging and may require the replacement of the entire metal roof for a lasting solution.

4. Overlaps

Metal roofs have areas where panels overlap, and roofers typically install rubber or mastic seals on both sides of the fasteners to secure the roof sheets together, preventing water infiltration.However, adverse weather conditions like strong winds and snow accumulation can displace metal roofing panels, leading to the gradual deterioration of these seals. As a result, water may penetrate through the gaps formed between the panels, causing leaks known as capillary draw or capillary action.

Roof repair for metal roofs differs from that of other roofing materials. The approach varies based on factors such as the cause of the leak, the degree of damage, and more. Repair options may include the following:

a. Replacing Screws and Fasteners

As previously outlined, screws can serve as entry points for water on metal roofs due to improper installation, damage, or natural deterioration. In such cases, it’s essential to engage a professional contractor to remove and reinstall fasteners correctly. However, when the damage extends beyond a few fasteners, this task becomes labor-intensive.

b. Applying Roof Coating

To revitalize an existing roof, professionals apply a roof coating, typically an elastomeric substance known for its stretchable properties. This method involves minimal tear-off and incurs limited expenses. Depending on your warranty, the application of roof coating has the potential to extend the lifespan of your metal roof by 10 to 20 years.

c. Replacing Your Roof

In some cases, a professional roofer may advise replacing your metal roof entirely. While this option can be relatively expensive upfront, it often proves to be a cost-saving measure in the long term, particularly if your current roof is aging or deteriorating. Signs indicating the need for a new roof include significant rust, numerous loose panels, and extensive leakage.

Regardless of your roof type, Alpha Design Services is ready to assist you 7 days a week, from 7:00 AM to 7:00 PM, all year round. For inquiries or assistance, please contact us at 410-390-0300 and schedule your Free Roof and Home Assessment customized to your specific service needs. With over two decades of service, our professional team is proud to serve local neighborhoods throughout the state of Maryland. Choose peace of mind and make informed decisions for your home improvement and roofing needs with Alpha Design Services!