Today's fireground, buildings, and occupancies present increasing challenges that have redefined tactical fireground operations and impact these operations on a wide variety of levels. This class presents insights on building construction for today's demanding fireground with a focused and high-intensity discussion of emerging trends in building construction systems, residential and commercial occupancy risks, collapse and compromise characteristics, the influence of construction on command decision making, hybrid commercial buildings, emerging cross laminate timber, mass timber construction, issues affecting large-area mega-mansions, rowhouses, and adaptive reuse of Type III-IV structures construction.