Limbach Holdings, Inc.
A specialty contractor that designs, installs, and services mechanical systems—chiefly heating, ventilation, air conditioning (HVAC), and plumbing—for commercial buildings such as offices, hospitals, schools, and industrial plants. Founded in Pittsburgh in 1901 by Heinrich Limbach and Evan Shaffer, the company grew into one of the largest mechanical contractors in the United States, known for its design-build work and building maintenance programs. The founding duo ran the firm from a single office more than a century ago, and Limbach's own website still recalls those early days as "from one office to across the country."