How to Screw Down Metal Roofing

April 16, 2024by Joe0

If you’ve been thinking about installing a metal roof, then you’ve likely come here to learn more about how to put it up the right way. Metal roofs are becoming much more popular lately, and there are plenty of great reasons that you might want one from your home, with their added durability, a wide range of unique styles, and more.

However, installing a roof can seem like a complex task and, indeed, if you do it wrong, then the roof that you install is going to lose a lot of stability as a result. Anything loose or installed improperly is at a much greater risk of flying off when it’s hit by bad weather.

In particular, when it comes to metal roofing, the thing you want to really make sure that you get right is screwing it down properly, which means choosing the right screws and the right location for them. If all goes well, your roof will be securely fastened and should last you for tens of years. Otherwise, you could end up with a loose roof that’s more likely to leak, come loose, and let water into the home more freely. 

Here, we’re going to look at everything you need to know about how to screw metal roofing. We’re going to look at the method, some tips to help you ensure that your roof stands strong, and, beyond that, what makes it such an effective and popular choice in the first place.

What is screw-down metal roofing?

Just to be clear what we’re talking about, screw-down metal roofing is a type of metal roof comprised of metal panels that are, as the name implies, held in place by screws. The panels overlap each other, and aside from screwing the panels into the roof below, you’re also screwing the panels into one another, forming a tight seal. Where you screw will depend on your preference and the manufacturer’s suggestions, but we’ll cover that later.

Metal roofing is an option that became very popular in the US in the 19th century. While screw-down metal roofs were initially most popular on things like garages, porches, and barns, they have since become a popular form of providing whole roofing systems for the home, as well.

Using the right screws for metal roofing

As small as screws and fasteners might be, they can play a major role in the success of your roofing project. They might be the least expensive part of the roof installation process, but if you get your choice of screw wrong, or mess up the installation, they can easily be the sole point of failure for the whole roof, so you can want to make sure that you do it right.

Your choice of screws is what prevents the roof from coming loose, letting in the weather, or even falling. As such, we’re going to look at what to consider when you’re choosing screws for your project. Here are a few elements that you need to consider:

  • Material: The type of metal that you’re screwing into is also going to affect the choice of the screw material, as well. As such, you should make sure that you’re aware of the roof type, and that you choose a metal that is different from it to reduce the chances of galvanic corrosion. As a quick rule, for aluminum roofing: use stainless steel type 304 screws. For copper roofing, use stainless steel type 410 with copper plating. For corten, any type of stainless steel should work, and for other metals, use zinc-plated screws.
  • Length: You want to make sure that you’re choosing a screw that is long to penetrate the material beneath the roofing by at least one inch. You’re also going to need fasteners long enough to penetrate throughout the entirety of the roof material.
  • Composition: Aside from making sure that you get the length and material right, you want to make sure that the screw itself is suitable for the job. First of all, it needs to have a rubber washer, which allows the screw to create a better seal, preventing rainwater from leaking through the screw hole. A metal cap should also be fitted onto the screws, making it easier to remove and install.

Tips for screwing down metal roofing

You might think that once you have the right screws, all you have to do is go to work. However, it’s a good idea to take your time and make sure that you’re carrying out every step as properly as you can. As such, here are some tips to follow during every step of the installation process:

Consider pre-drilling your holes

A lot of screws, nowadays, come with self-drilling tips, which means that they can be drilled directly into the roof without any need for pre-drilling. However, if you want to make sure that you’re extra precise, and want to make sure that the screw is guided properly into the material in straight lines, then pre-drilling might be a good idea. However, you should not pre-drill your roof if you’re drilling into metal purlins.

Choosing where to place your screws

The specific placement of your screws may vary depending on your preferences and the shape of the roof. A lot will place their screws on the ribs of the panels, which can help avoid issues with debris and water draining, whereas screws on the flat areas of the panel are going to be exposed to more water when draining. That said, some people still place their screws on the flat areas on the panel, which can lead to less chance of a screw pulling out when exposed to high winds. If you’re not certain which feels best to you, then you might want to check the roof manufacturer’s recommendations, which are likely to be on the manual for the roof panels.

Tightening your metal roofing screws

When you have screwed them in, then you want to make sure that you get the tightness of your metal roofing screws right. You want to ensure that they are tight enough to hold firm, but over tightening is a very common problem. You don’t have to keep tightening and tightening until you can go no longer. Overtightened screws are more likely to snap under pressure. That said, under-tightening the screws is likely to lead to leaks. Typically, what you want to do is screw until the rubber washer expands to the edge of the metal cap but not enough to go past it. If the washer can still be spun after you’re done, it’s likely not tight enough so a little more might be necessary.

Installing them straight on

When you’re fastening your screws to the roof, make sure that you do not put them at an angle, whatever you do. You want to take the time to make sure that every screw is straight and flush so that your washer is able to create a proper seal. If you screw things in at an angle, leaving them tilted or at an odd angle, then you’re going to have less pressure on one side of the washer. The washer will be loose there, which will allow water to leak below. Screwing straight into the roofing material makes sure that the washer is pressed down evenly on all sides, creating a nice, tight seal that isn’t going to let any water through.

Clean up after yourself

When you’re done installing your roof screws, you should take the time to clean up with a soft brush, or even a broom with softer bristles. Make sure that there are no metal shavings left on the panels. These can be abrasive if left up there and can cause spots of corrosion to appear, which you certainly don’t want.

The benefits of metal roof installation

It’s important to remember the reason that you’re doing all of this. A lot of people find that the benefits of a metal roof are well worth the cost and effort, simply because there are few materials that perform as well as metal does. Metal roofs are significantly more durable than shingles and, when installed properly, require much less maintenance. Metal roofs are also a lot better at reflecting solar radiation. Where shingles might capture and trap heat, leading the home to grow hotter, metal roofs do the opposite, allowing you to potentially save on your air conditioning costs.

Perhaps the greatest benefit of a metal roof is the peace of mind that you have a roof that is going to last you for a lifetime. Shingle roofs typically need to be replaced every twenty years or so, but that’s not the case with metal roofs. No, these roofs can last decade after decade, so long as you’ve made sure to install them properly.

Take the time to install your metal roof properly

By following these tips, you’ll have a much easier time finding the best placement for screws in metal roofing and also know how to install them correctly.

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RPS Metal Roofing & Siding, Inc is a manufacturer and distributor of metal roofs. Located in Welaka, Florida, our company has state-of-the-art manufacturing equipment resulting in fine quality metal roofs for commercial, residential and agricultural use.

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