Building envelope standards and practices have evolved over the past few decades in response to increased energy efficiency goals and a better understanding of Building Science. New materials, systems, and methods have been developed that reduce air leakage through building envelopes. Thermal protection requirements have increased and continuous insulation is often detailed better to avoid thermal bridges. A properly designed, detailed, and installed building envelope assembly utilizing these new products, systems, and standards will typically perform as expected, reduce energy usage, and provide a durable and long lasting building envelope assembly.
However, what if the installation is imperfect and air leakage occurs, or excessive moisture is introduced during construction? What if future wall or roof leaks cause water to become trapped within the assemblies? What if the components degrade over time and no longer fulfill their purpose? We have investigated many building envelope failures and found that air barrier, roofing, and waterproofing perfection is challenging to achieve. In some cases, moisture collects within the building envelope assemblies and needs to be removed
The goal of this course is to outline potential strategies to reduce or evacuate moisture from building envelopes without wholesale replacement. To accomplish this, the course will present case studies of a few existing buildings and new construction where we installed moisture monitoring data loggers to evaluate initial conditions and verify moisture reduction over time. The data loggers collected five-minute data for temperature, relative humidity, and moisture content and have been in place for over six years in some buildings. Moisture reduction methods in these studies include added thermal protection to reduce interior condensation, modification of heating and HVAC systems, and air movement strategies including directional fans, dehumidification, and in one case a roof ventilation system utilizing induction and exhaust fans. The success of these strategies was verified with empirical data.
Wade Vorley is an architect and registered roofing consultant at Wiss, Janney, Elstner Associates (WJE). Prior to joining WJE, Mr. Vorley worked as a roof installer, supervisor, project manager, and cost estimator for a roofing contractor in the Pacific Northwest. He has a master’s degree from UC Berkeley, focuses on building envelope investigation and design; and provides condition surveys, field investigations, repair designs, peer reviews, and litigation support. Mr. Vorley is published in trade journals, presents AIA accredited seminars, and conducts research. He has presented technical papers at the 2011 NRCA Symposium in Washington, D.C., the 2013 Waterproof Membranes Conference in Dusseldorf, Germany, the 2018 RCI Convention in Houston TX, and the 2018 ASTM E06/D08 Symposium in Washington D.C.