Integrated water-resistive barrier or building wrap? There is no question
The abundance of building product choices available today can make it more difficult and time-consuming to choose the right system components for upcoming projects. Simply being “built-to-code” is becoming a thing of the past with higher-quality products making a bigger entry into more traditional spaces. Additionally, a greater emphasis is being placed on creating more efficient, resilient, and healthier environments by architects, builders, and code regulators alike. So how can specifiers save time determining which products will stand up during and after construction?
It starts with the envelope
When it comes to durability, efficiency, and resiliency, there is one building enclosure system that has revolutionized wood-framed building envelopes. Created as an alternative to traditionally used wood sheathing with building wrap or housewrap, ZIP System® sheathing and tape strikes the balance between efficient installation and long-term water and air management. A structural one-rated engineered wood panel with an integrated water-resistive barrier (WRB), it eliminates the need for specifying an additional weather barrier. Completed with advanced acrylic ZIP System™ tape at panel seams and flashing details, the system delivers a continuous water and rigid air barrier in a simplified method. Code-compliant as an air and water barrier for roof and wall assemblies, as documented in Evaluation Service Report (ESR) 1473, the system is also backed by a 180-day exposure guarantee and 30-year limited warranty. This streamlined approach for weatherized roof and wall systems helps keep schedules on track and reduces the risk of repair delays.
“When we promise a finish or closing date, we do it with a lot of confidence, and a lot of that has to do with the ZIP System enclosure,” says Mike DeCesare, owner of Case Development LLC in Cleveland, Ohio. “Previously, we were using conventional [oriented strand board] OSB with wrap, rounding the building twice—first with the sheets and then again with wrap. With ZIP System sheathing and tape, the air and water barrier is built into the panel, which translates to one less time around the building, speeding up the install.”
DeCesare is among a growing nationwide population of architects, builders, and framers advocating the benefits of ZIP System® building enclosures. Introduced in 2006, ZIP System sheathing and tape is now widely used in a range of project types from custom homes to multifamily projects and light commercial builds. The ZIP System® portfolio of wall and roof solutions offers structural panels in a range of thicknesses, lengths, and even R-values, thanks to the line of ZIP System® R-sheathing panels with integrated exterior insulation providing R-3 to R-12 thermal resistance.
It is about delivering superior moisture management
A building’s first line of defense against moisture is its exterior cladding, but should that fail over time, the secondary line of moisture management must guard against water intrusion. Plus, multifamily and commercial buildings often remain exposed to the elements without cladding for extended periods during construction. The unique textured surface of ZIP System® sheathing is engineered to promote the drainage of bulk water. Testing under ASTM E2273, Standard Test Method for Determining the Drainage Efficiency of Exterior Insulation and Finish Systems (EIFS) Clad Wall Assemblies, confirms properly installed panels and tape perform substantially better than traditional housewrap offerings. Under third-party testing conducted by Architectural Testing Inc., ZIP System sheathing and tape achieved greater than 90 percent drainage, while the leading branded housewrap achieved less than 10 percent drainage.
The unique ZIP System sheathing manufacturing process combines the strength of advanced engineered wood structural panels with the protection of the integrated WRB fused onto the panel during the manufacturing process. This eliminates the risk of the crucial weather barrier ripping and tearing when exposed. In contrast, traditional building wrap or housewrap is often a separate component from the OSB sheathing installed onsite as an extra step in the framing process. Under this method, traditional building wrap can rip or tear under common jobsite conditions, including high winds or accidental byproducts of other building professionals’ work, resulting in additional time, work, and expense spent on the repair.
With ZIP System sheathing, the WRB is permanently fused, so there is virtually no risk of rips or tears, thereby ensuring the panel’s wood structure is not exposed to damage or detrimental weather conditions. The wood surface of a traditional OSB and housewrap system can be compromised when housewrap is ripped or torn, as a break in the wrap may expose the entire wood surface underneath to unfavorable weather or moisture. An integrated WRB and structural panel eliminates the risk of water getting trapped between the panel surface and the backside of the housewrap.
The system is also designed to allow walls to promote proper drying to the outside. To promote outward drying, the integrated ZIP System sheathing WRB is engineered with a permeability of 12 to 16 perms, which is higher than the engineered wood panel behind it. Again, since the WRB is fused directly to the engineered wood panel during the manufacturing process, the integrated system does not allow moisture to get trapped between the WRB and the panel face. Altogether, the panel is designed to effectively shed bulk water, while allowing the system to dry outwardly.
It is about providing a tighter air barrier
According to the U.S. Department of Energy, air leakage accounts for 25 to 40 percent of the energy used for heating and cooling in a typical home. Using ASTM E2357, Standard Test Method for Determining Air Leakage of Air Barrier Assemblies, a common standardized test method for measuring the air leakage of air barrier assemblies, third-party testing by Home Innovation Labs confirmed that ZIP System sheathing and tape provides a tighter air barrier assembly than traditional housewrap. The integrated WRB and structural panel system passed the test at the seven different air pressure levels required under the code-recognized test methodology, while housewrap failed at higher pressures, ripping or puncturing to expose the OSB surface beneath.
ZIP System sheathing and tape creates a durable, rigid air barrier to protect against both air infiltration and exfiltration to help achieve a tight building envelope.
When it comes to specifying products for continuous control layers in the building envelope, sheathing with an integrated WRB provides superior water and air management over traditional sheathing and building wrap for common wood-framed structures. ZIP System® products offer a range of structural panels and sealing solutions to meet project design and climate zone requirements. While there is no shortage of product choices, high-quality integrated systems should be considered for controlling water intrusion and air leakage and reducing installation steps, which can reduce room for error. To learn more about the science of ZIP System sheathing and tape, visit ZIPRevolution.com. To request an in-office CEU, Master Spec guide or building information modeling (BIM) materials, e-mail AIACEU@huber.com.
All information listed in this section was submitted by Huber Engineered Woods.
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