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Friday, April 14, 2023, from Noon – 1:30 PM Central
Norbert Krogstad (Wiss, Janney, Elstner Associates, Inc.)
Low sloped roof systems can develop condensation problems via different mechanisms than sloped roof systems. Unlike steep-sloped roof systems that use convection-driven and wind-driven venting to dissipate moisture that enters the roof systems from interior air, ventilation in low-sloped systems have many complicating issues. Changes in energy codes, new roof systems, and increased requirements for fire suppression systems have increased the frequency of these problems in new construction. Avoiding condensation in these systems is dependent on effective air barriers, avoiding direct air flow into framing spaces (from walls, ductwork, and other sources), approaches to insulation placement to allow the use of unvented systems.
The presentation will discuss condensation problems in low-sloped roofing systems and how to avoid problems in new systems and repair existing ones.
Learning Objectives (AIA credit will be available):
At the end of this program, participants will be able to:
- Understand the basic physics associated with condensation.
- Understand the role airflow in low0sloped roof condensation problems and sources of air pressure differences that cause airflow.
- Understand why venting low-slope roofs with rooftop vents or exhaust fans is often worse than not providing any ventilation.
- Understand design approaches for avoiding condensation problems in these systems.
Norbert Krogstad is a licensed architect in Illinois, Minnesota, Missouri, and Oklahoma. During the past 40 years at WJE, Mr. Krogstad has investigated and developed repairs for distressed conditions in several hundred new and existing buildings. Most of Mr. Krogstad’s projects involve building enclosure systems that are having condensation, water leakage, deterioration, or structural problems.
Mr. Krogstad has lectured at numerous conferences and continuing education programs and has authored or co-authored many papers and articles related to these topics. Mr. Krogstad is a member of the ASTM International (ASTM) where he is active on several committees concerning masonry wall systems. He was also on the ASHRAE Task Group that developed Standard 160 - Criteria for Moisture-Control Design Analysis in Buildings.