Metal roofs are integral to homes and commercial buildings, offering protection from the elements and structural stability. With the proper care for design, installation, and materials selection, a roof can last decades and withstand natural environmental effects — such as wind uplifts.
Whether you’re a homeowner looking to keep your home safe or a contractor striving to offer the best materials for your customers, it’s important to understand what wind uplifts are and how they affect a metal roof.
Sheffield Metals International (SMI) is a leading distributor in the metal roofing industry. We supply bare and painted metal coils and sheets, along with other metal roofing accessories, to our customers while providing them with the information and guidance they need to complete high-quality metal roofing projects.
Throughout our decades of experience, we’ve seen why roofs have succeeded and why, in some cases, they’ve failed to stand up to the harsh effects of wind uplifts.
In this article, we’ll talk about:
- What wind uplifts are
- How wind uplifts affect metal roofs
- What determines the severity of wind uplifts
- How to defend against wind uplift damage
By the time you’re done reading, you’ll have a better idea of what wind uplifts are and have a more comprehensive grasp of the topic.
What Are Wind Uplifts?
Wind uplifts are pressures on a roof that create a pulling effect, which can lift panels upward and, in some cases, cause damage to a roof that requires repairs or replacements. Wind uplift is a natural occurrence that happens constantly in different degrees of magnitude. Different wind loads can have different effects on different parts of the roof.
In some cases, wind uplift may be very minor and only slightly lift a roof’s panels. In the most extreme cases, wind uplift will be so powerful that it can rip a roof from its seams.
The amount of wind uplift you have will be dictated by the region you live in and the type of roof you have. And while wind uplift is in some ways inevitable, there are ways you can defend against it, such as making sure you get a robust metal roofing material and ensuring that you’re installing panels the correct way.
To start, it’s essential to understand how wind uplift works.
What Causes Wind Uplifts?
Wind uplift has a lot to do with aerodynamics. When you think of a car, you can envision the wind gliding around its design fluidly, allowing it to speed across a freeway smoothly. On the other hand, homes and commercial buildings are typically square structures, which obstruct wind currents and alter airflow, forcing different pressures to be applied to roofs.
When wind hits the wall of a building, it accelerates upwards and comes up over the corners and perimeters of the roof. As it does this, the wind swirls across the top of the roof, creating mini vortexes that apply both negative and positive pressure, also known as wind uplifts.
Negative pressure results in a pulling action on the roof, while positive pressure comes up from underneath roofing panels and pushes upwards.
Various factors will dictate how wind uplift affects your roof, such as your location and the weather in your area.
What Determines the Severity of Wind Uplifts?
There is always some type of force being applied to your roof, and wind uplift may happen in some small way frequently. The severity of that wind uplift, however, changes often, and it’s often dictated by several different factors, including the design of the roof, the type of structure, and the location.
The type of structure you’re working with will add or detract from the severity of wind uplift. Taller buildings typically experience harsher wind uplift since wind force tends to get stronger the higher a building climbs.
Your region will also control the severity of wind uplifts on your roof. Different regions will have different wind speeds. Those located in areas such as the Cayman Islands, where hurricanes are prevalent, for example, will experience very high winds. In contrast, those in Arizona may not experience that kind of severity.
When it comes to wind uplifts, location is essential, and you should be aware of what kind of wind your unique area gets when installing or purchasing a metal roof. With a durable and high-quality roof, you can be confident that your home will be well-protected from severe wind.
Just like different locations will experience different wind speeds, varying standing seam roof designs will experience different types of wind forces on parts of the roof. To understand it simply, imagine trying to pick a piece of paper up from a flat table. When you try to pick up the paper from the middle, it’s difficult. It’s much easier trying to pick up the paper from an edge and even easier doing so from a corner. The same concept applies to a roofing design and how wind reacts with the structure.
When it comes to standing seam metal roofs, wind uplift can have a particularly unique effect, so it’s essential to take an in-depth look at that relationship.
How Do Wind Uplifts Affect Standing Seam Roofs?
Standing seam metal roofs are one of the most durable and long-lasting roofing systems on the market, offering a smooth appearance while holding up exceptionally well against harsh weather. The design of a standing seam metal roof is affected in unique ways by wind uplifts.
Standing seam panels have a lot of flat space between each rib. When wind comes up over the top of the roof and negative pressure starts being applied, the center of that panel can be pulled upwards from the roof deck. This is also known as panel deflection. The more deflection you have, or the more your panels are being pulled upwards, the more pressure will be placed on the seams to hold the roof in place.
When the panels deflect, the seams could open up, resulting in a failure of the engagement of the seams, whether that be a snap-lock or mechanical seam system. This also puts pressure on the clips to hold your roof together.
While it’s important to consider the effects of wind uplift when it comes to standing seam metal roofs, some products will undergo rigorous testing to ensure that they hold up well even in extreme weather. Effective testing will ensure that roofs don’t suffer the harmful effects of extreme wind uplifts.
What Are the Potential Effects of Wind Uplifts?
Wind uplifts can cause many roofing issues, from gentle wear and tear to severe effects that require significant repairs or even replacements. Here are some of the potential impacts of wind uplifts.
Panel Separation and Clip Failure
The main issues that arise from wind uplift are panel separation and clip failure. The pulling effect of wind uplift causes stress on the panels to hold together, which in turn puts pressure on the clips. If enough pressure is applied, clip failure can result.
In the most extreme cases, wind uplift can be detrimental to a roof, creating failures to the point where it causes lasting damage. In these cases, wind uplift will cause building owners to make serious repairs or even invest in a completely new roof.
While wind uplifts can be harmful to roofing systems, there are ways you can prevent them from doing too much damage.
How to Defend Against Harmful Wind Uplifts
In some cases, it may seem like natural factors in your environment are out of your control. And while hail, extreme temperatures, and high winds are just a product of the region you live in, there are actionable steps you can take to protect roofs from the worst effects of wind uplift.
Consider Your Location
As mentioned earlier, different regions will experience different types of wind systems. Roofs in Florida require completely different design standards than roofs in Arizona because they need to hold up against harsh winds. Different areas of the country have varying minimum design criteria as it relates to wind uplift. Make sure you work with a contractor that understands these requirements and can deliver a roof that meets or exceeds these minimum standards.
Know What Your System Is Tested At
Roofs are tested at varying levels, so it’s important to know what your roof was tested at and how it will hold up in different conditions. Not all roof panels perform the same and some styles perform substantially better than others. You can contact a metal roofing supplier to understand testing specifics and be confident that the roof you’re getting is right for you.
Know What Your Clip Spacing Is
In theory, the more metal roofing clips you have in a design, the more stability you’ll have to hold down your roof, and pressure will be distributed throughout them so no one clip is bearing too much force. Your metal roof manufacturer should be able to provide the clip spacing required to meet your area’s minimum design standards.
Likewise, you should also look at the type of panels you have – wider panels will typically deflect more than narrower panels, which have less flat space to be affected by wind uplift.
Make Timely Repairs
Stay on top of any repairs to ensure your roof is in the best possible condition to defend against wind uplift. If there are already issues with your roof, wind uplift could expose those weaknesses and cause more problems. Making timely metal roofing repairs and getting routine inspections done can help identify any lingering issues before they become significant.
Find Qualified Installers
One of the most effective ways to defend against the effects of wind uplift is to make sure a roof is installed correctly. Standing seam roofs, especially, are intricate systems that require a knowledgeable installer to get the job done right.
Be sure to ask around for referrals, research online for metal roofing installers near you, or contact a metal roofing supplier to see if they can point you in the right direction.
Buy High-Quality Materials
It’s also essential to use high-quality materials for a roofing system. Excellent materials can last for decades and be robust even in harsh weather conditions. Find an experienced supplier to get you the lasting products you need for your roofing project. For metal roofing applications, we recommend products with stated warranties on paint of at least 35 years or more for PVDF. If using a Galvalume substrate, it should be a minimum of AZ50 on the coating weight.
Need High-Quality Metal Coils and Sheets for Your Roofing Project?
Wind uplift is an interesting topic many people may not know about or understand. However, it’s one of the most significant risks to standing seam roofing systems. With the right information, you may be able to find strategies to help you defend against wind uplift and find roofing materials that will stand the test of time. By now, you likely have a better grasp of what wind uplift is, how it works, and how it relates to metal roofing.
Now, you might be wondering about how wind uplift is tested or looking for installation best practices so that you can prevent wind uplift from damaging your roof. You can find more resources on metal roofing installation and best practices in our online learning center.
For more questions on wind uplift, or if you’re looking to find high-quality metal coils and sheets for your roofing project, feel free to reach out to Sheffield Metals International. Our expert team has worked with hundreds of contractors and architects to get them the ideal products for their metal roofing projects. We’re ready to help you find what you need.