All You Need to Know About Metal Roof Screws and Fasteners

When it comes to construction projects of any kind, it’s easy to overlook the importance of something as small and straightforward as screws and fasteners. Take, for example, a metal roof installation — fasteners make up less than one percent of the total cost, yet it is possible for the roof to fail due to issues with the fasteners. This could be from broken or incorrectly installed fasteners, worn-out sealing washers, or even using the wrong screws.

With that in mind, the following guide will provide an in-depth look at the types of fasteners available and help you decide which will be best for your specific project.

Fastener Identification

Before diving into different types of fasteners, it’s essential that you understand the anatomy of a fastener.

• Head: The head of a screw is the portion that sticks out, and it can be either flat or rounded. There are various head styles, including hex, hex washer, and pancake head.
• Drill point: The drill point is responsible for drilling a pilot hole in the material. There are three styles of drill point: Self-drilling, self-tapping, and self-piercing.
• Diameter: The diameter refers to the diameter of the shank (the portion driven into the material) and not the screw head.
• Thread: Threads are the ridges that run along the length of a screw that allow it to be screwed into the material.
• Length: The length of a screw is measured from under the head to the tip of the point.
• Material: The material of a screw affects the strength and durability of the fastener. Common materials include stainless steel and carbon steel.
• Coating: The coating affects a screw’s corrosion resistance. Galvanized screws are the most common.
• Sealing washers: Some screws have rubber sealing washers to ensure a watertight fit.

Factors to Consider When Choosing a Metal Roof Fastener

Now that you understand the anatomy of a screw, it’s time to figure out how to choose the right fasteners for your metal roof. The following are some of the most critical factors that need to be considered to choose the right screws for your project:

Matching Screws to the Colour of Metal Panels

Metal roof panels come in various colours these days, and you’ll want your fasteners to match. The last thing you’ll want is to see your screws because they are a different colour than your roof panels. Fortunately, screws come with different colour-coated fastener heads that match the colour of your roof panels, thereby allowing them to blend into your roof.

Choose the Right Screw Based on the Type of Material

Different types of metal roofing will require different types of screws. If two different metals come into contact with each other and are exposed to moisture, it can result in corrosion and damage to both materials. Therefore, choosing the right type of screw for your particular roofing material is essential. For example, aluminum and galvanized steel match well, as do copper and bronze.

What is the Correct Screw Length for Metal Roofs

The length of the screws you choose is also important to ensure the screw is long enough to hold the metal panels. The general rule of thumb is that there should be at least one inch of screw penetration. With that in mind, the following are a few tips on choosing screw lengths for metal roofing as well as metal siding:

Screw Lengths for Metal Roofing

1-inch pancake heads are the most commonly used screw for standing seam metal roofing. For 1/2-inch corrugated panels, you’ll need 1.5-inch-long screws. If the corrugated panels are 7/8 inches in height, you’ll need 2-inch-long screws. Finally, for R panels, 7.2 panels, and Ag panels, you’ll likely need 1-inch-long screws.

What Causes a Screw to Back Out of Metal Roof

Loose screws are an issue because they can cause metal roof panels to back out of their original position, leading to leaks and other issues. The following are a few reasons why this can happen:

• Thermal Expansion: Metal roofing materials expand and contract due to temperature changes, which can cause the screws to back out.
• Compression: Compression from heavy loads, such as snow, can cause the screws to back out.
• Gasket Deterioration: Gaskets between the screw head and the panel can deteriorate over time, which leads to loose screws.
• Water Damage: Water getting into the screw head can cause it to corrode and loosen.

How Often You Should Replace Fasteners on Metal Roof

Unless damaged or loosened, your screws should not need to be replaced and should last as long as your roof. However, it’s important to inspect your metal roof periodically and make sure the screws are tight and secure. If any screws have come loose, you should replace them immediately. You should also check for any other signs of damage, such as rust and corrosion.

What to Avoid When Installing Metal Roof Accessories

The following are a few things to avoid when using fasteners to install metal roof accessories:

• Using Dissimilar Materials: Make sure your roof accessories are made from a similar material as your roof panels. This will help prevent galvanic action and corrosion.
• Doing it Yourself: Not only is there a chance that you might install it incorrectly, but working on the roof without proper experience and training is dangerous.
• Choosing the Wrong Metal Roof Fasteners: Using the wrong screws can make the roof more susceptible to leaks and other types of damage.

We Offer the Best Fasteners for Your Metal Roof

At Ironclad Roofing, we have a wide range of metal fasteners to suit any type of metal roofing project. We offer the highest quality products with superior corrosion resistance, plus our highly-trained team is available to provide you with the best advice and support. Contact us online for more information about our metal roofing systems and services, or call us at 905-752-4685.