By Benjamin Meyer
In the ever-changing landscape of modern construction, owners and designers are facing an onset of challenges when it comes to building for resilience. Changes in energy codes, increasingly unpredictable weather events, and a growing understanding that rebuilding has significant embodied carbon implications make building for resilience more pertinent than ever. Defined by AIA as “mitigating risk for hazards, shock, and stresses and adapting to changing conditions,” building for resilience means going beyond current minimum code requirements.
Making future-focused project decisions in the design phase can have a significant impact on the durability of the building over time. Presenting a tangible solution in this effort, though often overlooked, is air- and water-resistive barriers (AWBs).
Understanding AWBs
AWBs are components of the building envelope designed to mitigate air and water infiltration into a structure. These barriers serve as a protective layer between the interior and exterior of a structure, preventing moisture intrusion and air leakage, which can lead to a host of issues such as mold growth, deterioration of building materials, and compromised indoor air quality (IAQ).
AWBs are typically installed during the construction phase and applied to the exterior structure of building enclosures. They come in various forms, including adhered and liquid membranes, each suited to specific design and environmental requirements. While often unseen, the importance of AWBs cannot be overstated, as they serve as a critical line of defense against the elements, ensuring the structural integrity and longevity of buildings.
The benefits of installing AWBs
Building safety
AWBs contribute significantly to building safety by preventing moisture ingress and air leakage, thus protecting against mold growth, rot, and structural damage. In the wake of rising and hazardous climate threats, implementing these systems can extend a project’s lifespan with increased resilience.
Beyond physical structure, AWBs promote health and comfort for all inhabitants. Poorly designed and installed AWBs can create unintentional leaks and uncomfortable hot or cold drafts throughout the enclosure. An airtight AWB installation enables the mechanical ventilation systems to perform with maximum efficiency, providing fresh air and filtered interior air to prevent the spread of airborne diseases. By maintaining a dry and stable indoor environment, AWBs promote occupant well-being while preserving the structural integrity of the building.
Impact on energy consumption
The construction industry is responsible for a significant portion of landfill waste and CO2 emissions. Now, traditional methods and materials must give way to more sustainable solutions. AWBs, when installed properly, can lead to substantial energy savings by reducing thermal loss and improving HVAC efficiency—lowering the contribution of harmful waste and energy.
Without proper airtightness, HVAC systems work overtime to regulate thermal loss, releasing even more carbon emissions. Reducing the need for heating and cooling energy, AWBs help maintain a consistent indoor temperature. This lowers utility bills and reduces greenhouse gas (GHG) emissions associated with energy production for a more sustainable and cost-effective built environment.1 Energy codes increasingly require whole-building airtightness performance testing to achieve the final certificate of occupancy.
Designing today for the future
Getting the building enclosures right upfront is vital for the long-term performance of the building. Unlike a lightbulb or HVAC unit that can be swapped out later if the initial design was a bit off or when the technology improves, building enclosures can be installed for generations before being upgraded. By effectively sealing buildings from external elements upfront, AWBs help mitigate the impact of weather conditions, including extreme heat, cold, wind, and rainfall. This role in maintaining the health and longevity of a structure underscores the importance of AWBs in modern construction practices. They can also result in decreased recurring repairs, conserving materials long-term.
Some products contribute to LEED through energy savings strategies and include elements made from 60 percent post-industrial recycled content of stainless steel, providing a materials-conscious approach that aids in overall environmental mindfulness.
Reducing energy consumption and material selection are only part of the larger challenge facing the construction industry. Beyond technology and materials, AWBs represent one tangible solution toward a broader commitment to innovation and sustainability to help future-proof today’s construction. As the industry progresses in this arena, there can be more conversations to uncover the environmental and overall health benefits of AWBs.
Implementation
In addition to recognizing the importance of AWBs, the construction industry must consider proper installation, specification, and application. Poorly designed or installed AWBs can compromise their performance, leading to moisture intrusion, air leakage, and energy inefficiency. The effectiveness of AWBs relies on understanding the building’s purpose and location and managing risks the building will experience in the future. Selecting the proper AWBs based on climate and weather-related risks is complex but essential, aiding long-term resilience.
To overcome this hurdle, proper training, adherence to best practices, and quality control measures are essential to ensure the effective implementation of AWBs in construction projects. This requires a commitment to quality, innovation, and continuous learning across an increasing number of trades and designers. Meeting the most current code and testing requirements is also essential, including a willingness to surpass established codes with voluntary standards such as those set by the Air Barrier Association of America (ABAA), LEED, Passive House Institute US (PHIUS), and the International Green Construction Code (IgCC).
Conclusion
Embracing change and collaboration is imperative in harnessing the full potential of AWBs in construction. By recognizing the multifaceted benefits of AWBs in building safety, energy efficiency, and climate resilience and addressing the challenges of implementation through innovation and collaboration, the industry can pave the way for a more resilient built environment.
The construction industry must prioritize integrating AWBs into building design and construction practices, ensuring they become standard components of resilient and sustainable buildings. Changing energy codes are leading to onsite testing and installed performance requirements for AWBs. This requires a collective effort across stakeholders, including architects, engineers, builders, policymakers, and manufacturers, to promote education, innovation, and best practices in AWB implementation.
The industry can future-proof buildings and AWBs through collaboration and shared vision as essential components of resilient and sustainable construction practices that exceed the minimum criteria. By harnessing the power of AWBs, it is possible to create structures that contribute to a healthier, more sustainable world for generations to come.
Notes
1 Energy cost savings are not guaranteed, and the savings may vary based on climate zone, utility rates, radiative properties of roofing products, insulation levels, HVAC equipment efficiency, and other factors.
Author
Benjamin Meyer, AIA, LEED AP, serves as building enclosure business director for Siplast. He also serves as chair of the ASHRAE 90.1 Envelope Committee, director of the Air Barrier Association of America (ABAA), past LEED Technical Committee member, and past technical advisor of the LEED Materials (MR) TAG.
Key Takeaways
With changing energy codes, increasingly unpredictable weather events, and a growing understanding that re-building has significant embodied carbon implications, building for resilience is more pertinent than ever. Amid the urgency, commercial building owners play a crucial role in resilience. Emphasizing high-performance air- and water-resistive barriers (AWBs) becomes pivotal, forming a continuous shield against moisture damage. This proactive approach mitigates risks associated with increased rainfall and extreme weather events. By implementing such strategies, there is potential to future-proof the built environment, offering resilience against the escalating threats of hazardous weather.
