About Capitol Building Supply
Quality. Service. Reliability.



Welcome to Capitol Building Supply (CBSI) – home to the largest selection of quality construction materials and building supplies across the Mid-Atlantic region. Choose a topic below to learn more about:
Our Company – Our parent company GMS, careers with CBSI, credit application and other valuable customer resources
Articles – product releases and other updates
Our Services – delivery, pick-ups, specialty orders, showrooms and more
Our Products – drywall, steel, acoustical tiles, insulation, tools, lumber, etc.
Our Yards – locations in Maryland, Delaware, Virginia, and the D.C. metro area