Alternative Solutions

Problems and drawbacks of conventional methods have led to alternative solutions.

Extruded Polystyrene Sheathing

This is a light weight alternative that is not a structural panel. It has no nail holding strength and can be easily punctured. The vapor permeance of extruded polystyrene sheathing is less than 3. It does have insulating properties and some types can be installed as a water-resistive barrier and air retarder with special detailing. Seams must be taped.

Roll- or Sprayed-On Water-Resistive Barrier

The primary advantage of this method is that it will stay on the wall without ripping or tearing. However, roll- or sprayed-on water-resistive barriers must be installed at a specific thickness, and there are different installation instructions for different substrates. Further, a dry time is required, multiple coats are often necessary, and there are temperature restrictions for installation. The surface must be clean before applications, and consistency is difficult to achieve. All in all, this method entails an exacting and time consuming installation process.

OSB Panel with Integrated Moisture Barrier

Rising energy prices, growing awareness of building performance, environmental sustainability, and changes in building codes have led to products that represent optimal solutions for structural sheathing, moisture management and superior air barrier performance. One such product that represents an optimal solution for moisture management is a structural panel like OSB and plywood but with an integrated durable moisture barrier. This continuous water and air barrier also improves energy efficiency by significantly reducing air leakage. Once the panels and tape have been installed, a lasting protective barrier has been established as a permanent part of the structural panel, making it impossible for water to become trapped between the panel and barrier.

These products are engineered with the optimal permeance to allow the wall system to breathe and dry out, while also preventing intrusion of exterior moisture. A water-resistive barrier must have a higher permeance than the OSB panel to allow for outward drying of the system. On the other hand, the barrier must not be overly permeable and allow exterior water vapor to enter the wall sheathing and system. This is a common issue when moist cladding such as brick, stucco or stone is exposed to heat from the sun. The vapor permeable-moisture barrier is 12-16 perms.

Seam sealing tape can be used as flashing tape, which minimizes the chance for flashing installation errors. Unlike with many conventional products, windy weather does not impede tape application. Some wall panels are also manufactured with a screen texture which provides added grip for ladders and handling as opposed to many housewraps which are smooth and slippery, creating a safety hazard for ladders leaning against the structure. Some manufacturers offer a 30-year system warranty. Properly installed, these panels and tape keep water from entering the wall system and provide a drainage plane to help water exit.

“Integrated wall sheathing was part of a 'perfect' wall assembly, providing our weather resistive barrier, air barrier, thermal barrier and drainage plane. Testing has shown that the seam sealing tape provides one of the toughest air barriers available. This system addresses the growing need to make buildings more durable and energy efficient,” says Architect Chris Laumer of Giddens LG Squared in Atlanta, Georgia.

Atlanta architect Jose E. Tavel agrees after use of the system on an architectural studio. “For the new studio we had interior and exterior walls panelized off-site with the system sheathing. The panels were delivered with the sheathing installed and the seams taped. Once the panels were erected, the final sheathing was installed very quickly and had the building watertight and on our way to the LEED Silver rating,” says Tavel.

In an added advantage, panels go up quickly for a stronger, drier, faster seal, creating the ideal building envelope. Installation is relatively easy and can be completed in two steps—fasten panels and tape the seams. The wall system is code recognized as a water-resistive barrier and a Type 1 air barrier. The roof system is code recognized as a roofing underlayment. All panel seams must be taped with the prescribed seam sealing tape.

The OSB roof panel with integrated moisture barrier can result in a streamlined roofing installation. The panels eliminate rework, and after roof system is taped, the building can be considered dried in and mechanical contractors can begin rough-in. The panels, which have a uniquely clean and uniform appearance, can be exposed for 180 days.

The products are only allowed in Type V construction and in construction permitted under IRC and IBC. Roof panels can only be used on roofs with a minimum 2:12 slope. The products are approved for adhesively-attached Exterior Insulation Finishing (EIF) systems.

Moisture and Air Leakage Management

Properly constructing a building envelope for optimum moisture and air leakage control leads to sustainable, energy-efficient buildings. As technology advances, buildings systems become more effective. One such example is the high-performance structural panel complete with integrated air and moisture barrier—a system that installs easily and accurately and performs reliably, providing architects with a valuable tool to achieve green buildings that save energy costs and maximize user comfort.

 

Huber Engineered Woods LLC continually strives to create innovative products that suit their customers’ needs. Each one delivers outstanding performance, easy installation, and greater strength in single family, multifamily, and light commercial projects. Huber’s ZIP System® Roof and Wall Sheathing are structural wood panels with built-in protective barriers, eliminating the need for building wrap or felt and providing a continuous rigid moisture and air barrier that optimizes energy efficiency. Additionally, Huber’s AdvanTech® Subflooring product is proven to achieve a superior combination of strength and moisture resistance—for subflooring that won’t swell, cup, delaminate, or bounce even under the toughest conditions. Visit Huber’s new online architectural library to explore their offering of innovative, high-performance, and environmentally responsible building solutions. On this site, you can quickly access and download all of the product information you need to specify ZIP System® sheathing or AdvanTech® subflooring for your next project. Visit www.HuberArchitectLibrary.com.