As environmental concerns loom, rainscreen cladding assemblies are an increasingly popular solution to deflecting water and ensuring air flow while maintaining diverse aesthetic options. And this façade design style’s popularity shows no signs of slowing in the near future. Versatile with a wide variety of today’s most sought-after cladding materials (like fiber cement, metal, terracotta, high-density laminate or composite panels, and more)—rainscreen manages to help protect the building and maintain curb appeal. If you’re not doing so already, it’s time to consider this growing trend.
Eco-Conscious and Eco-Driven
Essentially a double-wall construction built to help keep moisture out of the building, rainscreen systems are seeing rising demand. By creating a gap between the exterior wall sheathing and exterior siding, rainscreen systems provide extra support against potentially damaging water intrusion by providing a capillary break in which water can drain, while also helping protect the building’s structure from mold, warping, and other harmful effects.
Increased instances of rainstorms, hurricanes,1 and other weather phenomena in recent years have the construction industry embracing inventive solutions for mitigating potential water-related damage. As such, rainscreen systems have gone from a small-scale home-protection option introduced in the 1960s to a broadly accepted worldwide construction industry juggernaut. Thanks to the attachment methods and cladding types that a rainscreen application offers, it has become a helpful option in managing water intrusion.
Initially popular primarily across residential buildings, it’s now a growing trend in the office and institution market, as well.2 By 2018, it was already a $116+ billion global industry and expected to reach $183.3 billion3 by 2025—that’s an anticipated compound annual growth rate of 6.7%. For office buildings alone, it’s projected to reach $60.75 billion globally by 2025.
Moisture protection aside, sustainability is another attractor. Two additional factors contributing to this surge in rainscreen usage are its energy efficiency and eco-friendliness. The additional layer of building exterior helps increase thermal insulation, by reducing thermal bridging, which helps retain heat while also reducing condensation and potential mold growth. And many cladding options, such as aluminum, are recyclable and can be pre-built for less energy usage onsite.
“The facade is one of the most significant contributors to the energy budget and comfort parameters of any building,” as the American Society of Civil Engineers (ASCE) notes. Controlling the physical environmental by minimizing heat transfer through design can have a direct effect on the amount of energy that will need to be used to maintain inside comfort despite outside climate dips and spikes. “High-performance facades need to block adverse external environmental effects and maintain internal comfort conditions with minimal energy consumption.”
Given that the assembly style can help decrease the amount of energy required to heat, ventilate, and air condition a building, demand for rainscreen continues to rise amidst growing awareness of sustainable construction processes.
Devising a System That’s Right for You
Today’s rainscreen types range from vented systems, drained and vented systems, and pressure-equalized systems—variations on the gapping design and compartmentalization within the wall assembly. All of these assembly styles help set up the water-resistive barrier (WRB) for success, further protecting the inner wall structure from the impact of bulk water and wind.
Sheltered by the rainscreen, the WRB (comprised of the substrate covered by a water-resistive membrane) can more effectively shed intrusive water and dry without permeating through to the rest of the wall materials. Essentially, the rainscreen takes building water management from a single-layer system to a multi-layered one.
To ensure air movement behind the cladding, the air gap is created between the house wrap and the back of the siding using cladding clips or furring to leave space between the materials and provide a drainage plane. This acts as a first line of defense against moisture intrusion, directing water away from the water-resistant layer of wrap to dry. Then the WRB works to protect the building’s exterior walls from further moisture penetration, with flashing adding extra protection at the more vulnerable points.
To maintain constructability to bring your precise design vision to life, look for a versatile water-resistive barrier solution that will pair effectively with today’s popular cladding choices. No one on your project team wants to see your best laid blueprints mangled to unrecognizable second-rate adaptations to save cost and rework constructability issues throughout the building process—least of all, you.
For both performance and design, DensElement Barrier System accommodates Rainscreen assemblies with a variety of cladding options. Integrated WRB sheathing combines the water-resistive barrier, air barrier, and sheathing—removing the need for a separate WRB application. While there are several distinct approaches to accomplishing this, Georgia-Pacific approaches it uniquely. DensElement Barrier System fills microscopic voids in the glass mat and gypsum core via AquaKor Technology, creating a hydrophobic, monolithic surface that blocks bulk water while retaining vapor permeability.
Then DensDefy Accessories finish the system, consolidating the components needed for a complete, air-tight wall assembly with compatible materials from a trusted manufacturer. DensDefy Liquid Flashing completes the DensElement Barrier System by sealing joints and seams for a tight envelope, and DensDefy Transition Membrane covers joints, gaps, and distinct transitions as needed.
In third-party rainscreen assembly testing (PDF),4 the DensElement Barrier System was noted to maintain water holdout at normal water pressures and volumes when cladding fasteners were correctly spaced with drainage space behind the cladding fastener. And when tested with three of the leading rainscreen subframe systems, the DensElement Barrier System resisted water penetration after being subjected to increasing pressures and durations. When installed under Georgia-Pacific manufacturer guidelines, it provides excellent water penetration resistance with the commonly used subframe systems.
The DensElement Barrier System’s scientific innovation helps stop water on the surface of the board and enables vapor to dissipate through the system rather than trapping it within the assembly. The drainage space that is created by installing cladding over the subframe adds to the building envelope’s ability to drain incidental rainwater that gets past the cladding deflection layer, which further reduces the risks of bulk water entering the interior side of the wall assembly during a storm.
If you’re not already, it’s time to look deeper into a rainscreen wall assembly’s ability to better ensure that your projects’ constructability and water protection concerns don’t come at the cost of your design vision. For more information on the versatile and reliable WRB-AB system available at your disposal, visit DensElement.com.
Author: John Chamberlin is the Direct, Product Management at Georgia-Pacific responsible for DensElement Barrier System and the DensDefy line of products. Chamberlin has worked in the building products industry for his entire career with most of his work focusing on new product development for disruptive technologies in the building envelope space.
Chamberlin is actively involved in the building industry, serving as a director for the board of the Air Barrier Association of America and member of multiple committees and an active participant of his local Building Enclosure Council. Chamberlin graduated from the University of Tennessee with a Bachelor of Science degree in Marketing and later received his M.B.A. from Emory University.