Rainscreens Grow in Popularity
Words: Bronzella Cleveland
Free training supports proper design, detailing and installation
Rainscreen wall systems are a growing segment of the masonry market. More than just a veneer or façade, the systems are an efficient response to managing moisture, vapor, air and thermal transfer. Rainscreen panels are manufactured in easy-to-handle weights and sizes, reducing waste and equipment needs. They come in a variety of shapes, sizes, textures and materials, including terra cotta, porcelain, stone, calcium silicate and fiber-reinforced concrete.
Rainscreen wall systems include an exterior cladding supported by a clip and rail metal subframe, air space, insulation, water/air/vapor barrier and a support wall. As building science advances, so, too, has the wall system, incorporating more control layers to optimize building performance. Rainscreen systems are a natural evolution of anchored veneer and cladding, which are often separated from the backup, creating a cavity wall system. Modern rainscreens use even larger open venting, allowing air to flow freely and evaporate moisture that enters through the exterior wall cladding. Additional water/air/vapor barriers also work to prevent unwanted penetration to the support wall.
In addition to encouraging evaporation of moisture in the wall cavity, ventilated rain screensallow for increased drying capacity of the exterior wall assembly. This creates less risk for veneer staining and spalling, improves the longevity of veneer anchors, and helps protect masonry from other damage caused by excessive moisture. Because the ventilated systems offer superior moisture management, they perform well in harsh weather conditions, helping to increase the performance and life expectancy of buildings.
Mason contractors and craftworkers with the International Union of Bricklayers and Allied Craftworkers (IUBAC) can offer a single-source approach to rainscreen installation and are uniquely positioned to do so, with an understanding of the entire building enclosure. They
have skill and training in working with tight tolerances, humoring materials, and in dealing with unit masonry/panel construction. Additionally, the subframes used in rainscreen systems are similar to traditional stone veneer systems — another skill set that contributes to a more efficient installation.
The International Masonry Institute (IMI) offers free training and continuing education to help designers, construction managers, contractors and craftworkers learn how to properly design, detail, bid and install rainscreen wall systems. IMI’s Rainscreen Expo series — geared specifically toward designers and contractors — offers in-depth technical sessions, as well as the chance to handle product samples exhibited by rainscreen manufacturers and suppliers. In 2017 and early 2018, the Expo traveled to Chicago, Illinois; Providence, Rhode Island; Pittsburgh, Pennsylvania; the San Francisco Bay Area; and Los Angeles, with future events planned for New York City (April 2018) and Detroit (May 2018). Details will be announced at http://imiweb.org/event-calendar/.
To help prepare masonry contractors and craftworkers to effectively install rainscreens, IMI and the International Masonry Training and Education Foundation (IMTEF) also offer training for IUBAC members that includes shop and classroom instruction. Contractor training through IMI includes an estimating and project management module. IMI/IMTEF training centers are ideal places for contractors to practice rainscreen installation and learn more about productivity and details prior to bidding projects.
Architectural firms and construction managers agree that rainscreen systems are not a trend, but are here to stay. The advantages the systems bring to construction make them an attractive masonry solution for building and design challenges, especially where moisture management and energy efficiency are key.
Contributed by The International Masonry Institute