Earlier this Fall, I attended the Wagdy Anis Symposium, an in-depth dive into the building envelope. The symposium addressed a variety of challenges and opportunities for designing a high-performance building envelope, including thermal insulation, thermal bridging, and existing building interventions.
Here are seven key takeaways from the sessions and the breakout conversations to consider while designing the building envelope:
1. Understand the impact of altering existing building envelopes.
There is a surplus of existing buildings in our built environment. To improve the energy efficiency of the building, it is critical to understand how measures to make the envelope airtight and how an increase of relative humidity of the interior environment impacts moisture movement and the overall performance of the existing envelope.
2. Investigate existing conditions and perform an existing design analysis.
The ability to view the composition of the exterior wall further informs the envelope analysis during the design phases. Viewing existing conditions leads to more thorough detailing once areas of necessary intervention and improvement are identified.
3. Evaluate your building envelope design to identify locations and types of thermal bridges.
Some different types include Clear Field Thermal Bridge, Linear Thermal Bridge or Point Thermal Bridge. Understanding the where, how, and why thermal bridges occur creates better details, a better performing envelope, and a more durable building. It is important to note that some jurisdictions require thermal bridge reporting and documentation.
4. Review the exterior assemblies in terms of the four plans of water condensation.
This includes the Face of Cladding, Back of Cladding, Face of Exterior Insulation, and Water Resistive Barrier (WRB). When you understand the potential areas for water ingress, you can identify a strategy for water control and redundancy.
5. Document the building envelope.
Elevate every portion of the building exterior to indicate R-values and U-values of systems and assemblies. Include window and wall areas for calculations. For exterior wall assemblies, indicate material composition, but also R-values and U-values of the components, referencing ASHRAE. Provide a schedule to identify each type of weather-resistive barrier in the project, and reference projects details of each condition. Documenting the building enclosure provides a comprehensive view of the exterior envelope and a reference tool for assemblies.
6. Consider the durability of the building components and the life of the building.
Review the Owner’s project requirements to help inform the commissioning process. Consider the macro environment of the climate and the interior building environment: how do the building and its materials operate in its climate? What are the “regional mechanisms of deterioration”? Consider the microenvironment: What happens on the material surfaces which could impact performance? Based on these considerations, you can select materials that support the building’s service life and create an efficient enclosure.
7. Share your knowledge.
How can the knowledge we learn during these symposiums be better communicated to rising architects and students? How can we constructively teach the basics of the building envelope and building technology to students? Understanding these basic concepts would help the transition from school into practice. Mentoring rising architects remains integral to our practice but learning this information while in school provides student with fundamental knowledge required for project documentation and construction.