Masonry Magazine August 2016 Page. 40
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By Steven Fechino
Rainscreen veneer terra cotta during installation.
RAINSCREEN WALLS HAVE HAD A FEW DIFFERENT DEFINITIONS OVER THE YEARS. Rainscreens can be designed with products and configurations that assist in creating both pressure-equalized and non�equalized or drained/back ventilated systems -all still in line with the correct definition, but resulting in some industry confusion.
What Makes a Rainscreen?
THE TERM RAINSCREEN originally referred to the outer shell of the fas:ade, usually an aesthetically based material that functioned as a barrier to protect the building from weather or man-made elements. Weather, of course, is wind, rain, humidity, temperature and sunlight, whereas man�made elements can be anything that impacts the structure, such as sprinklers, surplus snow pushed against the struc�ture (common in northern states), flying debris and noise. There are many other elements, but the point is that the rainscreen is a protective barrier. Its components are en�gineered to function as a complete system: the rainscreen material, the type of channel and clip arrangement used to fasten the rainscreen veneer, the dimension of the air gap, the three-dimensional drainage mesh, and the air barrier and flashings.
Rainscreen, when defined as the fas:ade material, is typi�cally a terra cotta, precast, composite or metal panel, or even a very thin stone with lightweight structural backing. The lightweight material is a composite fastened independently to a framework that supports the fas:ade to the substrate and creates the mounting attachment points for the fas:ade material. Rainscreen fas;ade material can be installed with a gasket-sealed, material-to-material joint (horizontal and vertical joints) or with open material-to-material joints (horizontal and vertical joints).
The term pressure-equalized system has led some to believe that sealed walls will be drier than those that have open joints. Incomparison to cavitywall construction, sealedwalls are defi�nitely the preferred choice to stand the test oftime and perfor�mance, but a rainscreen wall is slightly different
Cavity Wall vs. Rainscreen Construction
MAsONS ARE MOST FAMILIAR with cavity walls. While we have seen mass and composite walls, 99 percent ofour veneer work has been in cavity wall construction. Cavity wall con�
38 I MASONRY � August 2016 � www.masoncontractors.org The Voice of the Masonry Industry