Tag: wind

Metal Roofing & Hurricane Season Part 2: Tips to Help Your Customers Protect Their Metal Roof

Posted on by Tyler Roose

As with any kind of roof, proper maintenance is integral to protecting against hurricane damage. In part 1 of this series, we reviewed how choosing metal roofing can help prevent wind damage to homes and businesses. And while choosing metal panels as a roofing solution is the first step to damage prevention and increasing roof longevity, there are additional precautions your customers can take to protect their investment.

ABC Blog | Metal Roofing and Hurricane Season

Professional inspection 

Prevention is key. To maintain the strength and durability of metal roofs, your customers should have a licensed metal roofing professional inspect it regularly. While your customers can manually inspect their roof themselves, a qualified roofing inspector can thoroughly examine it, identify areas of concern and provide a detailed report including roof life expectancy, photos and repair estimates. Professional inspectors can also make hurricane preparedness recommendations based on your customer’s roof type.

Ensure all fasteners are secure 

Fasteners are the key to preventing roof uplift as a result of high winds. Be certain the roof is properly fastened to the truss and that the correct fastener type, diameter, length and thickness are used. Consider the thickness of the panel, substrate and any other materials between the panel and truss to when selecting fastener length to ensure roof panels are secure. (Screws often need to be triple the length to accommodate the thickness of what’s being screwed down.) Additionally, although placement of fasteners may seem like a minor detail, screw pattern can actually be a major factor in a roof’s structural integrity. Be sure to follow the panels manufacturer’s instructions to the letter during installation.

Check for rust, loose screws and flaking paint 

When rust develops on metal, it can accelerate degradation, compromising the integrity of your customer’s structure and leaving it vulnerable—particularly in inclement weather. While ABC offers Galvalume® metal panels that prevent rust from occurring, standing water and heat from direct exposure to the sun can degrade this protection over time. Therefore, it is important that customers regularly check for rusty and loose screws as well as flaking paint which can also cause rust development. If rust is found, advise your customer to contact their roofing contractor for repair options.

Install hurricane straps

An added layer of protection from high winds, hurricane straps (or roof tie-downs) securely tie rafters to load-bearing walls. Made of galvanized metal, they can attach to most roof types, protecting it and the structure beneath. Hurricane straps can also help keep a roof from detaching and causing damage to nearby structures and objects. Many homes already have them (depending on how old the roof is), but even structures with hurricane straps should be checked to make sure they were installed properly.

Add roof reinforcements

Although most metal roofing is resistant to wind-related damage, adding reinforcements can decrease the likelihood of damage. This is particularly true if your customer’s building project is located in a hurricane-prone area. To reinforce their metal roof, your customers can add sturdy overlapping materials on top such as heavier metal panels or two-by-fours. A professional roofing contractor can advise your customer on the best reinforcement option for their structure.

Brace gable ends

Gable ends experience a lot of exposure to high winds, making them vulnerable to wind damage. If your customer’s structure has a gable end, they should ensure that it has been solidly built and appropriately braced.

Trim your trees 

Trees that hang over your customer’s roof can be dangerous any time of year, but particularly during a hurricane. Falling tree limbs can cause severe roof damage, allow water into the structure, cause electrical issues or even injure someone inside. Trimming trees to is an easy way to prevent damage and injury.

Perform an interior inspection 

If your customer is experiencing issues with their roof, chances are that they will also see damage inside their structure. Your customers should be aware of any spots, stains, peeling paint and daylight seeping in. These are all serious indicators of a compromised roof and should be addressed immediately.

Secure the Yard

Unsecured items around your customers’ property can become a major threat to your customer’s home or business during a hurricane. With strong winds, patio furniture, trampolines, grills and even potted plants can become dangerous projectiles. If these objects strike your customers roof, they could cause severe damage. Customers should move small items inside and secure larger items with rope or zip ties.

Choosing metal panels as a roofing solution is the first step to preventing building damage during hurricane season. There are, however, extra precautions your customers can take to prevent damage and protect their investment.

For additional information on metal roof performance during hurricane season, read part one of our blog series. For additional tips on how to storm-proof your roof, reach out to your local ABC representative today.

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Note: This post was updated from a previously-published version.

Metal Roof Pitch Part I: Engineering and Strength Considerations

Posted on by David Lester

Whether you’re an owner who needs to consider roofing material options because of the nature or design of your building, or a distributor/contractor whose job it is to recognize whether a suggested design will or won’t work based on a range of circumstances, it is critical to understand the engineering behind why roof pitch and tensile strength are important on a metal building project. In part one of our series, we look at the engineering and strength considerations that need to be taken into account when designing or specifying a building, while part two will review the best type of metal panel to use based on the pitch and end-use of your building,

Engineering Considerations:

Ideally, your roof pitch will be the “sweet spot” between having a roof pitch that’s so shallow that the beared load is increased and having a roof pitch that’s so steep that wind uplift probability is increased—a factor which can also vary based on the building width. Specific engineering considerations with regard to roof slope include:

  • Snow Load Requirements: lower slopes create more load that the roof/structure must support. For example, when you have a flat roof and it snows, the snow will stay on the roof, adding more weight; on a sloped roof, a good amount of the snow will slide off of the roof, so the load will remain in an acceptable range the structure can support.
  • Wind Load: Preventing roof damage from high winds is largely dependent on roof geometry, slope and building material used. If outside air is allowed to penetrate a structure through cracks and other openings when wind flows over a building, the air pressure beneath the roof assembly increases. When this pressure becomes greater than the pressure directly above the roof (which happens as wind flows over a building), this can cause upward force on the roof system, leading to loss of structural integrity and significant damage. Wind uplift rating and minimum slope requirements are dictated by building codes in the market, so be sure to check with your local municipality for specific details.
  • Water Diversion: the steeper the pitch the faster it will channel and divert water, preventing it from pooling and causing other issue like mold, mildew and paint degradation. As with the snow load considerations mentioned above, the less additional weight burdening the roofing system, the better.
  • Minimizing Debris: steeper-sloped roofs also help minimize the chance that debris, mold and mildew have to build up on the roofing system. Unless there is a catastrophic weather event that drops large amounts of heavy debris—tree branches for example—there is a small chance that debris on a roof of any slope will exceed its ability to carry the load. However, because the more debris is able to slide down and off of a metal roof, the less that needs to be manually cleaned. Additionally, access to and cleaning the eaves of sloped roofs is much easier and less time-consuming that trying to perform the same maintenance on a roof with less slope.

The Strength of Metal Panels:

  • Tensile strength: This refers to the panel’s ability to resist breaking when it’s placed under pressure or tension—meaning the panel has a measured ability to bend under a certain amount of stress before it snaps. Galvanized steel panels can withstand between 50,000 and 80,000 pounds of pressure per square inch (50 KSI – 80 KSI)—significantly higher than the tensile strength of other roofing materials. Despite this, metal panels remain lighter and more impact resistant, keeping the likelihood and cost of repairs to a minimum. Check the tensile strength of your metal panels with the manufacturer and be sure to reference common testing standards related to roof slope, including ISO ratings and ASTM standards that test tensile strength.
  • Steel Hardness and Density: While it can generally be assumed that thicker-gauge panels are stronger, the type of building construction, location and end-use can affect the choice in panel thickness. Buildings such as pole barns, post-frame buildings, warehouses and garages can require roof panels to span longer distances and therefore require thicker panels as they are more structurally sound. These thicker panels will also aid in reducing the chance of collapse under the weight of snow and water—particularly when the roof pitch is low. For smaller buildings—like residences—with supporting trusses and purlins that are typically closer together, thinner panels can be used in conjunction with thicker trim for an economic, structurally ideal residential metal roofing system. See our blog on metal panel gauges for more.

Conclusion:

Following common standards, doing adequate research and conforming to manufacturer guidelines regarding slope will ensure you’re reaping the full benefit of your metal roof panel selection. For more information on metal roofs and to learn more about recommendations on roof slope, contact your local ABC representative today.

Additional Resources:

For more information on slope requirements, visit NRCA’s website. For more information on steep-slope metal roofs and their benefits, visit the Metal Construction Association’s website.