ThirdWall Construction | Maryland General Contractor | ThirdWall Construction ThirdWall Construction Maryland General Contractor Building Partners for Life Achieving Your Vision Since 1987 For more than three decades the ThirdWall Construction team has built exceptional projects and durable industry partnerships in the metropolitan Washington DCBaltimore region the kind that are forged from shared experiences and tempered by the bond of persisting through the hard times and the good times. Safety ThirdWall Construction always strives to stay in compliance with the standards introduced by the Occupational Safety and Health Administration OSHA. Markets We Serve ThirdWall Construction works across multiple markets to deliver service to a range of clients throughout the Baltimore and D. C.