Charter Oak Building Maintenance, or COBM, has been servicing Connecticut, Massachusetts and Rhode Island since 1988 with a management team comprising over 80 years of experience in Commercial Janitorial Services. Today we have grown to over 300 employees and are based out of our new 25,000 sq. I just wanted to say how great the floors looked when we came back from break yesterday! Thank you for completing our requests and resetting the condition of our floors. So far, I think the new night crew member is a great addition to the team!