Standing Seam Spotlight: An Educational Resource for Metal Roofing Professionals

When designing and specifying a metal roof, a wind uplift analysis is crucial to ensuring that the desired panel profile, width and gauge will meet code requirements. International Building code (IBC) requires that pressures are determined for an individual structure in accordance with ASCE 7, and recommend ASTM E 1592 testing to demonstrate that the allowable wind uplift capacity of the proposed roofing system meets or exceeds the design wind uplift loading on the individual structure.

Basic building information is all that is required to run a wind up-lift analysis using ASCE 7-02 in conjunction with ASTM 1592. Most quality metal roofing manufactures will provide you with this type of engineering. And since the total roof design can be affected by the results of a wind uplift analysis, including type, width, and gauge of panel, material, underlayment, nail board and deck, obtaining a wind uplift analysis prior to designing or specifying a roof will eliminate unforeseen costs and risks.

For example, a designer may be considering an 18-inch, 24-gauge architectural panel, with clips spaced 4-feet on center. But when a wind uplift analysis concludes that in order to remain compliant using the intended architectural panel system, 12-inch 22-gauge panels must be installed 2-feet on center, and that an underlayment will also be needed. This revelation will dramatically impact the cost of the intended system.

The same analysis also reveals, however, that an 18-inch 24-gauge structural panel with clips spaced 4-feet on center will comply and require only perimeter underlayment. So, while the designer had chosen what he believed to be a cost-effective architectural panel, the wind uplift analysis exposed potential “hidden” costs

with the architectural system. The analysis also showed that the actual lower-cost solution is the more reliable and resilient structural system, since it meets code requirements using a lighter gauge material with a wider seam, and reduces labor costs with no underlayment required and fewer clips to install.

The now well-informed designer can recommend a high performance structural panel with a much better water-tightness warranty while preserving the budget by considering the total cost of the roofing system. So, don’t throw caution to the wind by looking merely at the panel cost to choose your roofing system. Obtain a wind up-lift analysis, and equip yourself with the information you need to choose the right system for your individual project.

Volume , Issue 7

In This Issue Featured Article: Don't Throw Caution to the Wind Previous Issues: Issue 1: Must Meet Building Code Issue 2: Recycled Materials Issue 3: Ahhh… Symmetry Issue 4: Mid-Year Cost Update Issue 5: Choosing Metals Issue 6: Three Wet Threats Know Your Metal Roofing Systems Structural Systems s Most capable of withstanding high uplift pressures s Designed for watertightness s Does not require decks or underlayments s Used in deck applications for strength, wind uplift resistance, water-tightness and low slope Architectural Systems s Least resistant to wind up-lift pressures s Primarily decorative, requires substrate, steep slopes, and waterproofing s Typically will not meet ASTM E 1592, particularly in high- wind regions Hybrid systems s Structural or architectural depending on slope s Can meet ASTM E 1592 requirements with moderate pressures s May not meet code requirements in coastal areas		Don’t Throw Caution to the Wind By Mark Ricigliano and Bobby Addison When designing and specifying a metal roof, a wind uplift analysis is crucial to ensuring that the desired panel profile, width and gauge will meet code requirements. International Building code (IBC) requires that pressures are determined for an individual structure in accordance with ASCE 7, and recommend ASTM E 1592 testing to demonstrate that the allowable wind uplift capacity of the proposed roofing system meets or exceeds the design wind uplift loading on the individual structure. Basic building information is all that is required to run a wind up-lift analysis using ASCE 7-02 in conjunction with ASTM 1592. Most quality metal roofing manufactures will provide you with this type of engineering. And since the total roof design can be affected by the results of a wind uplift analysis, including type, width, and gauge of panel, material, underlayment, nail board and deck, obtaining a wind uplift analysis prior to designing or specifying a roof will eliminate unforeseen costs and risks. For example, a designer may be considering an 18-inch, 24-gauge architectural panel, with clips spaced 4-feet on center. But when a wind uplift analysis concludes that in order to remain compliant using the intended architectural panel system, 12-inch 22-gauge panels must be installed 2-feet on center, and that an underlayment will also be needed. This revelation will dramatically impact the cost of the intended system. The same analysis also reveals, however, that an 18-inch 24-gauge structural panel with clips spaced 4-feet on center will comply and require only perimeter underlayment. So, while the designer had chosen what he believed to be a cost-effective architectural panel, the wind uplift analysis exposed potential “hidden” costs with the architectural system. The analysis also showed that the actual lower-cost solution is the more reliable and resilient structural system, since it meets code requirements using a lighter gauge material with a wider seam, and reduces labor costs with no underlayment required and fewer clips to install. The now well-informed designer can recommend a high performance structural panel with a much better water-tightness warranty while preserving the budget by considering the total cost of the roofing system. So, don’t throw caution to the wind by looking merely at the panel cost to choose your roofing system. Obtain a wind up-lift analysis, and equip yourself with the information you need to choose the right system for your individual project. For help determining the right kind of system for your project, contact the Engineering department at IMETCO. For more information about symmetrical panels, click here. © 2006 IMETCO (Innovative Metals Company, Inc.)
For more information on this topic, please call IMETCO at 800-646-3826 or send an e-mail to learn@imetco.com. If you would like to schedule an onsite presentation or speak with a metal roofing specialist, please contact sales@imetco.com. 2070 Steel Drive Tucker, Georgia 30084 (800) 646-3826 www.imetco.com
Neither Innovative Metals Company, Inc. (IMETCO) nor any of its affiliates makes any representation or warranty of any kind with respect to the materials and information contained herein. Although IMETCO attempts to provide accurate information, this bulletin is intended for general reference and informational purposes only. IMETCO assumes no responsibility for errors or omissions in the content contained in, or directly accessible from, this bulletin, and makes no commitment to update such information. IMETCO shall not be liable for any damages relating to your use of, or reliance upon, this bulletin or any of its content.