Starting next week, ARCHITRENDS is launching a three-part series on building better walls, thanks to a big assist from the Building Science Corporation (BSC) – a consulting and full-service architecture firm for commercial, institutional and residential buildings. An internationally recognized organization, BSC’s focus is preventing and resolving problems related to building design, construction and operation. Probably best known for their expertise in moisture dynamics, indoor air quality and forensic investigations into building failure, BSC advocates for sustainable design, energy efficiency and environmental responsibility in building technology. Their website www.Buildingscience.com is a free online resource. Better Walls for Buildings The perfect wall is an environmental separator—it must keep the outside out and the inside in. Therefore, in a world of perfects walls, a wall assembly must control rain, air, vapor and heat. Functional, resilient walls need four principal control layers: moisture control layer air control layer vapor control layer thermal control layer As BSC points out, if you can’t keep the rain out, don’t waste your time on the air. If you can’t keep the air out, don’t waste your time on the vapor and forget about thermal. The perfect wall includes a water control layer, with an air control layer and vapor control layer positioned directly on the structure, and a thermal control layer covering the other control layers. Expansion, contraction, corrosion, decay, ultra violet radiation (basically, most bad things!) are all functions of variations in temperature. So, control layers need to go on the outside to help the structure weather temperature extremes and protect it from water in its various forms, as well as ultra violet radiation. The “clever” wall, as BSC calls it, uses building material that combines all four controls. Thus, air moisture barrier systems (AMBs) and exterior insulation finish systems (EIFS). The most “clever” walls utilize integrated, stand-alone systems that can work together to form a waterproof air barrier for all types of vertical, above-grade wall surfaces, engineered for fast, easy application. (Example: StoGuard) These continuous-insulation (ci) wall systems can provide superior air and weather tightness, long-lasting thermal performance, durability and are available in a wide range of decorative and protective finishes. Look for PART ONE in our series next week; it will focus on Moisture Control.
We’re all familiar with the power that comes from teamwork, including the teamwork involved in constructing buildings. Whether its design, systems, skilled labor or the products used in construction – all the pieces need to fit together to form a cohesive structure. Like all teams, there is always a member that helps strengthen the group and allows contributors to perform better. For EIFS (Exterior Insulation and Finish Systems) that critical impact player, providing additional team support, comes in the form of reinforcing mesh. EIFS are typically made up of several different layers, and reinforcing mesh is one of the strongest components enhancing the performance, durability and aesthetics of the system. Mesh works a bit like a bulletproof vest: the network of fibers in the vest works together to redistribute and absorb the impact of a bullet. Mesh helps redistribute stresses on a wall surface more evenly, thus providing additional strength. Mesh forms the center of the EIFS defense in a fire or a Category 5 hurricane, assuming it is mesh that has passed a barrage of third-party EIFS testing — from NFPA 285 (fire performance testing) to Miami-Dade County Hurricane testing. It is incumbent on EIFS manufacturers to test and qualify all components of their systems to ensure the safety compliance and performance resilience of a building. And it’s just as important for EIFS installers to be a part of the team, to only use tested, proven mesh products and to follow instructions for proper installation of the mesh.
A recent study published by Environmental Health Perspectives (EHP) suggests that Green Buildings create optimized conditions for health and productivity. In a series of experiments, indoor environmental quality (IEQ) factors for both “green” and “conventional” buildings were simulated in a controlled environment that included office workers, and the researchers measured variables such as carbon dioxide variation, ventilation and exposure to volatile organic compounds in the building atmosphere. The results? On average, cognitive scores for the two groups of workers were 61% higher for those working in a building with green features than with conventional construction. In other words, green building can potentially deliver a smarter workforce.
The recently completed Boys & Girls Club of America in Hobbs, New Mexico was built with a continuous insulation system that combines energy efficiency and aesthetic appeal. The attractive 28,000-square-foot project is a study in green technology thanks to the use of StoTherm ci Essence, a water-drainage system that includes an air and moisture barrier beneath it. The full system consists of six components: air and moisture barrier, adhesive, continuous insulation, reinforcing mesh, base coat and finish coat. The project was recently featured as an “EIFS in the Spotlight” posted by the EIFS Industry Members Association (EIMA), demonstrating that even community-based non-profits can benefit from a quality exterior insulation and finish system! Here’s a cool video that provides a virtual tour of the design for the new Club. https://youtu.be/BNPPXfWOliw
As popular building materials, Exterior Insulation and Finish System (EIFS) and stucco often appear similar — if not the same. However, EIFS and stucco couldn’t be more different. Stucco, dating back to the Greeks and Romans, is composed of Portland cement, sand and water. EIFS, a lightweight cladding system, is comprised of a polystyrene insulation board secured to the exterior wall with an adhesive or mechanical fasteners, then reinforced with an acrylic plaster and fiberglass mesh on top, and finished with an acrylic and polymer coat that is both colorfast and crack-resistant. Some of the most notable differences between the two can be detected in energy and thermal efficiency. Unlike stucco, EIFS serves as a continuous insulation system with no thermal bridging due to fasteners, which helps reduce building operation costs as well as air infiltration. EIFS also has the ability to achieve infinite design options with its wide array of aesthetic choices. EIFS can can look like nearly any material on the market; something stucco cannot achieve.
In the U.S., the International Building Code and ASTM International define Exterior Insulation and Finish System (EIFS) as a non-load-bearing, exterior wall cladding system that consists of the following: an insulation board attached either adhesively or mechanically, or both, to the substrate; an integrally reinforced base coat; and a textured protective finish coat. Prior to 2000, EIFS were barrier systems, meaning that the EIFS itself was the weather barrier. After 2000 the EIFS industry introduced the air/moisture barrier that resides behind the foam. Today, EIFS is one of the most tested claddings in the construction industry. Research conducted by the Oak Ridge National Laboratory and supported by the Department of Energy, has validated that EIFS is the “best performing cladding” in relation to thermal and moisture control when compared to brick, stucco, and fiber cement siding. In addition EIFS is in full compliance with modern building codes, which emphasize energy conservation through the use of ci (continuous insulation) and a continuous air barrier. Their growing popularity is related to the desire for energy efficiency combined with design flexibility.