Moisture protection is a major consideration in any building design. Without proper moisture control your building is subject to all sorts of issues from mold and sick building syndrome to structural failures.
Rainscreens offer a great moisture control solution to many exterior finishes, even siding. But what is a rainscreen?
A rainscreen is a wall construction in which you separate the exterior finish from the exterior wall to allow for water to dry behind the finish. Research has shown that the old way of thinking, "keeping the water out" is a thing of the past. The name of the game now is to let the water out and allow the substrates to dry. No matter the exterior finish, water is more than likely going to get behind it. Materials like brick and stucco are notorious for soaking up water due to their porosity. Even siding allows for water intrusion.
Siding Rainscreens
The traditional method for siding installation is to attach the material directly to the wall sheathing and weather barrier. The better practice for moisture control, however, is to apply the siding material to furring strips on the exterior and provide proper ventilation at the top and bottom of the wall to allow for the water to dry and seep out. Traditional techniques of brick veneer have been using this practice for years with the air-gaps, ties, and weep systems.
Stucco Rainscreen
For other products like stucco, a similar attitude should be taken. There are a lot of great products out there that help achieve the rainscreen for stucco. The goal is to create capillary breaks between the stucco and the wall by using weather barriers with rough textures that allow the stucco to stand off and offer the air gap that is crucial to behind the wall drying. Dorken Delta-dry is a product recommended by building science gurus like Matt Risinger to offer this level of rainscreen protection. Check out their products at www.dorken.com for more information. Be sure to check the vapor permeability of these barriers especially before placing them with faced insulation. Placing two vapor barriers in a wall system is never a good idea due to trapped moisture within the wall cavity.
From wood to tiles, exterior facades simply work better with the rainscreen approach. Check with your design professional and facade consultants to help you protect your next project. Or feel free to reach out to our team if you have any questions. We are here to help.
© 2019 by Clements Wimsatt Architects PLLC
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