At Durability + Design’s inaugural Material Selection Conference last week (Sept. 26), the themes that prevailed were data collection and communication. Though different challenges were discussed — from air leakage to moisture damage — the resounding message was: know your materials inside and out.
The one-day forum focused on the capability of coatings to manage moisture intrusion into exterior walls, and how liquid-applied air barriers can limit heat, air and moisture transfer through walls. The effect of permeance on exterior wall coating performance, as well as how specific coatings and water repellent brands performed on exterior walls were also discussed.
Manufacturer representatives participating in panel discussions offered their opinions on a variety of scenarios and recommended applicable products. Chuck Duffin, Ed Telson, and Tyson Lodge, representing Sto Corp., participated in these panels, educating attendees on how Sto coatings and air moisture barrier products perform on exterior walls in different conditions and circumstances.
Andre O. Desjarlais, program manager for the Building Envelope Systems Research Group at Oak Ridge National Laboratory, discussed the importance of WUFI software (an acronym for Wärme Und Feuchte Instationär—which, translated, means heat and moisture transiency) and why this hygrothermal modeling is valuable based on the wide range of materials available today consistent with the drive for energy efficiency.
While WUFI models yield a lot of data for designers of durable building envelopes, understanding this data and using it appropriately are critical for achieving the construction of energy-efficient, moisture-resistant walls, roofs and basements. Again, the need for knowing your products and how to apply them was reiterated.
The value of using the web-based Energy Savings Calculator developed by ORNL, along with quality assurance and installation requirements for liquid-applied air barriers, were also discussed to ensure building envelope energy efficiency and air tightness. It was noted that air leakage rates of a building depend on multiple variables, including envelope airtightness, HVAC system operation, occupancy, weather and the stack effect. Fluid-applied air barrier products and installation considerations were also debated.
The overall objective of the event was about making buildings last longer by integrating design objectives with exterior performance objectives, selecting materials wisely and knowing those materials. Regardless of which products are selected for durability and design, the manufacturers, architects and contractors in the audience seemed to agree that working closely with, and consulting, manufacturers regarding air barrier and wall coating products was the best way to ensure successful project outcomes.