Common causes of leaking metal roofs

6 Common Causes of Metal Roof Leaks Around Screws

A metal roof offers a reliable, durable solution for protecting a building from the elements. The materials are environmentally friendly, and these roofs provide excellent energy efficiency. Despite its strength, metal roofing material is penetrable. Leaks can occur near the areas where contractors used screws to secure the roofing panel.

Why Do Metal Roofs Leak at the Screws?

Specially designed metal roofing screws create a watertight seal by compressing a rubber washer at the base of the screw head. However, water may penetrate the roof for several reasons.

1. Selecting the Wrong Screw Type

The metal screw installation process involves fastening the metal sheets to underlying beams consisting of timber-steel composites, trusses or purlins. It’s imperative to choose screws with the appropriate drilling point size to match the material’s thickness. You can make the correct choice for your current roofing job by checking the vendor’s list of metal screws and their drill point capacities to locate the best option for your needs.

The metal screw’s length is another vital factor when preventing leaks. To determine the appropriate screw length, add the roofing sheet corrugation depth and the thickness of the underlying truss or purlin and increase this sum by two to three full thread lengths. You’ll also need to account for the rubber washer’s thickness when performing the calculation.

The screw’s thread type also plays a significant role in the evaluation process. Metal screw threads range from coarse to fine. Choose the former version when working with thinner sheets — under 4.5 millimeters — and the latter for thicker material — more than 4.5 millimeters.

2. Over-Driving the Screw

Some roofing contractors apply extra torque when tightening metal screws to ensure a secure fit. However, too much torque can cause the screw’s rubber washer to lose elasticity and eventually break. It could also damage the roofing panel.

A properly torqued metal screw will seat firmly without compressing too tightly against the surface. Ensure that the gasket isn’t bulging at the sides of the washer flange.

not making a screw tight enough can cause leaking roofs

3. Under-Driving the Screw

Not making the screw tight enough prevents the rubber washer from seating properly, resulting in an inadequate seal against the surface. Applying additional torque is a simple remedy for this situation.

Even if you supply sufficient torque, selecting a screw with the incorrect drilling tip capacity can lead to under-tightening and cause leaks — another reason to carefully select the appropriate metal screw type.

4. Misaligning the Screw

Driving the screw at an improper angle can also cause metal roof leaks. A crooked screw can prevent the rubber washers from sitting against the surface. It may also cause overcompression on either side of the hole, resulting in premature gasket damage.

A properly driven metal screw should sit flush with the roofing pane. If it appears misaligned or skewered, you can typically correct the issue by unfastening, removing and re-torquing the screw. Check the sides of the hole for damage before reinserting the screw.

5. Missing the Framing or Strut

Contractors may experience leaks even if a screw appears to be installed correctly. This situation typically occurs when the screw hasn’t seated properly grabbed onto the underlying frame or strut. Always double-check to verify that the screw is secure and will perform well.

6. Using Defective Screws

Screw quality can vary widely between brands. For instance, a roof may leak near the screws because the screw manufacturer chose cheap rubber material with a shorter life expectancy and insufficient resistance against the elements. Frequent temperature changes can also cause screw degradation over time.

It’s critical to partner with a metal screw supplier that makes delivering high-quality products a top priority and supports them with exceptional service.

Make All Points Fasteners Your One-Stop Metal Screw Supplier

At All Points Fasteners, we sell fasteners to professional roofing contractors like you. We offer top-quality products from leading manufacturers, ensuring they’ll meet your performance and durability expectations.

Our team strives to establish long-term partnerships with every customer by providing the excellent service you demand and deserve. We’ll help you locate the right metal screws for your projects, including hard-to-find fasteners for unique applications. Our attention to detail ensures you get the products you need quickly to keep your projects on schedule. Plus, affordable prices can help your roofing business save money on essential supplies.

Do you have questions about the common causes of metal roof leaks around screws? Call us at 800-483-6354 to speak to one of our friendly, knowledgeable representatives. You can also contact us online to request a customized quote.

Head Screw Lady Since 1986! Specializing in breaking down the language barrier between suppliers and end users. During her 35 years working in the fastener industry, MaryLouise has worked directly with end users, contractor’s, OEM’S and DIY, as well working within the import industry, working with fastener manufacturers and distributors. This has given her the unique perspective of having the technical knowledge needed to perform in the fastener world but also be familiar with the needs of end users who don’t necessarily know the fastener jargon or applications to know exactly what they need for their jobs.