# Joseph Lstiburek

joseph lstiburek (, pronounced STEE-brek) is a forensic engineer, building investigator, building science consultant, author, speaker and widely known expert on building moisture control, indoor air quality, and retro-fit of existing and historic buildings.Lstiburek is an adjunct professor of Civil Engineering at the University of Toronto; an industry consultant specializing in rain penetration, air and vapor barriers, building durability, construction technology and microbial contamination — and an advisor on numerous prominent building envelope failures. He consults regularly on building code and industry standards.Widely known for his "Perfect Wall" concept, Lstiburek identified four key control layers within the building envelope (rain, air, vapor and thermal) critical to a building's behavior, long-term performance and viability. He is a proponent of understanding the concepts that allow older buildings to survive over time in harsh climates — and mimicking those concepts with contemporary construction.