Built-Up Roof Systems in Denver

Built-up roofing assessment and replacement for Denver's aging downtown and mid-rise commercial buildings - legacy coal-tar and asphalt BUR systems on the 17th Street corridor, honest end-of-life guidance, and replacement scopes engineered for Colorado's 30 psf snow load.

Denver's downtown core and the 17th Street office corridor carry a meaningful inventory of 1950s through 1980s built-up roofing. Most of it is at or approaching end of life. We inspect it, document it, and give you a written assessment - including the honest recommendation when full replacement is the only viable scope.

Built-up roofing (BUR) - multiple plies of asphalt-saturated felt mopped together with hot asphalt or coal tar, topped with gravel or smooth surfacing - was the standard commercial flat-roof system in Denver from the 1920s through the early 1980s. The office and commercial buildings that define Denver's downtown core - along 17th Street, the Lincoln Center corridor, the Golden Triangle, and the Commerce City industrial zone - were predominantly roofed with coal-tar or asphalt BUR systems during that construction period.

Denver BUR systems from the 1950s and 1960s were built with one of two binder materials: coal-tar pitch or oxidized asphalt (Type III or IV). Coal-tar BUR is actually more durable in the long run - coal tar self-heals minor surface cracks and has better water resistance than asphalt BUR under Denver's freeze-thaw cycling. Downtown Denver buildings with coal-tar BUR from the 1960s that have been adequately maintained and are still watertight are not unusual. The limitation is disposal: coal tar is a regulated hazardous material under EPA guidelines, requires licensed waste hauling, and adds significant cost to removal on the downtown Denver projects where landfill access is restricted.