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. In 2001, The Wall Street Journal called Lstiburek "the dean of North American building science." Early career While working towards his bachelor's degree, Lstiburek also worked as a residential construction manager for Product Design Development Corporation. After graduating he became president of Inertia Development Corporation, a company that built and tested twenty low-energy houses. He went on to work for the Housing and Urban Development Association of Canada (HUDAC) from 1981-1982 where he was involved in the Canada-wide Super Energy Efficient Housing R-2000 program and became the Director of Research. While studying for his master's degree, he worked at the University of Toronto Centre for Building Science and later served as president of Building Engineering Corporation, a building sciences and components company in the residential construction industry. He also briefly worked in the commercial construction industry as a senior engineer for Trow in Toronto. After receiving his master's degree, Lstiburek worked in the United States as a consultant with Dames & Moore, a Chicago-based engineering consulting firm specializing in building sciences and construction technology. In 1990 Lstiburek became a principal at Building Science Corporation. Recent career In the 1990s, Lstiburek worked with Pulte Homes to reduce utility costs of their residences by 30% without increasing construction cost or changing their size, shape or look. Lstiburek suggested five changes, and the prototype home subsequently received Nevada's home energy Five Star rating. In 2005, with Hurricane Katrina's inundation of New Orleans, Lstiburek noted that significantly more older, elevated homes constructed with traditional, water-tolerant methods (masonry and plaster, without cavity insulation)