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Maryland Department of General Services Announces Completion of Maryland State House Cleaning

First Cleaning to this Extent in 20 Years

ANNAPOLIS, MD – The Maryland Department of General Services (General Services) today announced the successful completion of the State House facade cleaning. Since April, the main entry into the State House, including its portico, columns, and both side walls, have been covered by scaffolding. During this time, stone repairs were made and all areas of the facade have been carefully cleaned of biofilm and stains through a sophisticated laser process, resulting in a cleaner, brighter State House.

“The Maryland Department of General Services takes great pride in being the agency responsible for our historic State House,” said Secretary Ellington E. Churchill, Jr. “By embracing 21st century technology, we have given this historic building its first thorough cleaning in 20 years, with no damage to its structure.”

Carbon deposits and biofilms are biological growth that over time will dissolve a stone’s surface. Through direct observation of the stonework, General Services consultants believe many areas of  the State House facade have lost approximately 1/8” of its surface. Left unattended, the result is greater surface erosion. Complicating the project, stonework is pointed by differing mortar systems including the original lime base mortar, old concrete mortar, and hard white caulk that was poorly applied. The deteriorating joints also allow water to infiltrate the building envelope.

The Maryland State House is the oldest operating state house in the country and also the oldest building in the General Services’ portfolio of state-owned facilities. Responsible for its maintenance, General Services contracted CSOS-Conservation of Sculpture & Object Studio, Inc. to clean the State House using a combination of dry ablation and wet ablation processes. The dry ablation process is performed with lasers alone, while the wet ablation process required the use of a minimal amount of distilled water. Unlike typical stone cleaning techniques, this process does not use harsh chemicals.

The black carbon deposits and biofilm were successfully removed. In addition, portions of the portico that are not normally accessible, were made accessible which allowed for repairs to prevent future infiltration of moisture. The results of this restorative cleaning campaign are expected to last 20-25 years.


About DGS: The Department of General Services is responsible for essential services and programs administered on behalf of the state, including procuring goods and services; designing, building, leasing, managing and maintaining facilities; leading energy conservation efforts; and providing essential services such as fuel management, disposition of surplus property and records management. The Department of General Services Maryland Capitol Police maintains safety and security at state buildings.