Tag: steel

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.

Your Guide to Steel-Curtain Roll-Up Doors

Posted on by Jessica Taylor

No building is complete without a door. In this blog, we investigate steel-curtain roll-up doors and how they deliver form and function across a wide variety of uses.

What are Steel-Curtain Roll-Up Doors?

You see them everywhere. They’re used at your local schools, recreation and retail centers, and government, medical and office buildings. They provide access and security for storage units whether applied in backyard sheds, residential garages or commercial storage facilities. And, they are also an integral part of agricultural structures, transit stations, freight buildings and warehouses.

Made of a curtain (sheet) of durable, secure steel and designed to provide quick, easy access to both commercial and residential buildings, these doors open by traveling vertically, but gather into a roll at the top of the door instead of sliding along tracks. And while they can be used in a myriad of applications, with so many door options available in the marketplace today, why are so many people opting for steel curtain roll-up doors?


Why Steel Roll-Up Doors?

Long-term Value:
Roll-up doors made of steel are generally less expense to purchase initially and they save money over the course of their lifespan. Not only do they last longer, but they also require fewer, less expensive repairs and are more durable than wood, aluminum or fiberglass products—particularly in challenging environments. In addition, steel is more energy-efficient, saving on heating and electricity costs throughout the year.

Security:
Exterior doors are inherently the most vulnerable points of many buildings, so reducing the likelihood of theft, fire, vandalism and contamination is the best way to keep your property secure. More impenetrable than doors made from wood, fiberglass or aluminum, steel doors with standard stainless steel latches are better able to protect against unwanted entry, fire, noise, vandalism and contamination from exterior elements, providing reliable security and peace-of-mind.

Durability:
Steel is a resilient material manufactured to protect against extreme weather conditions and harsh usage environments. Unlike doors made from other materials, steel roll-up doors can endure the wear and tear of heavy traffic usage and can be outfitted with rust-resistant components including spring coatings and bottom bars to further extend their longevity.

Longevity:
While wood doors are susceptible to warping and rotting, aluminum doors can quickly become dented and fiberglass can easily crack—all of which require replacement—with proper installation and maintenance, metal doors can last 30 years or longer. The high-quality primers and paint coatings used on steel doors protect against chipping and scratching, keeping the doors looking better longer.

Easy Maintenance:
Steel roll-up doors require little-to-no maintenance and are easily replaceable—making them one of the most reliable, cost-effective options in the industry. ABC’s doors are unique in that they feature gear-driven tensioning brackets that ensure safe and easy adjustments that can be made on site and with minimal down time.

Appearance:
Steel roll-up doors are available in a wide variety of sizes, styles and colors. In addition, manufacturing improvements and advances in coating and paint products enables customization to suit even the most unique aesthetic requirements.

Space-Savings:
Because roll-up doors open vertically and are gathered into a roll instead of sliding along tracks, they take up little overhead space while enabling convenient and easy access.


How to Select the Right Steel Roll-Up Door:

Whether you are replacing doors on an existing building or sourcing them for a new project, be sure to consider the below factors before purchasing:

Use:
The door you need will depend on its intended use. Light-duty doors are manufactured to meet the specific and unique demands of small structures, portable buildings or recreational facilities while heavy-duty doors meet the needs of more demanding environments like commercial freight and utility buildings, warehouses and agricultural facilities.

Environment:
It is vital to consider your geography when selecting steel roll-up doors. If your project is located in a region susceptible to high winds from weather events including hurricanes, tropical storms and tornadoes, a wind-rated door tested in accordance with International Building Codes and that complies with your insurance requirements should be considered. Check both local and national building codes to understand if you need wind-certified doors, which can dramatically reduce maintenance and replacement costs as well as minimize downtime.

Warranties:
Be sure that you are familiar with and fully understand the warranty options available on the products purchased. It is common for doors and door components to be covered by a product warranty, while the coil coatings and paint are warranted under a second that should include considerations for film integrity as well as both chalk and fade.

To learn about ABC’s roll-up door solutions, visit our Roll-Up Doors product page or contact your local sales representative.