A Cup of Joe: Continuity of Control Layers


In high performance building enclosures, the perfect wall has four control layers located exterior to a structure: water, air, vapor, and thermal. Controlling water is always the first priority and the most important. Control across the field of a wall or roof is the easy part. However, the majority of leaks occur at transitions and interfaces between elements. Problems happen where things come together – the connections between roofs, walls and punched openings such as windows and doors. According to Dr. Lstiburek, in the last decade we have successfully combined the water control layer, air control layer and vapor control layer into a single layer. During installation, the water resistive barrier is integrated with flashings at windows, doors, and other penetrations to complete the water control layer.


About Joe Lstiburek, Ph.D., P.Eng., ASHRAE Fellow, Principal, Building Science Corporation:

Joe Lstiburek is the founding principal of Building Science Corporation, one of the most influential, innovative, and respected building science firms in North America. Dr. Lstiburek’s work ranges widely, from providing expert witness testimony to overseeing research and development projects, to writing for the ASHRAE Journal. His commitment to advancing the building industry has had a lasting impact on building codes and practices throughout the world, particularly in the areas of air barriers, vapor barriers, and vented and unvented roof assemblies.

Dr. Lstiburek is also an acclaimed educator who has taught thousands of professionals over the past three decades and written countless papers as well as the best-selling Builder Guides. His commitment to education earned him the hailing “the dean of North American building science” by the Wall Street Journal. You can find additional details on Dr. Lstiburek on our About the Blog page.