Originally constructed in the late 1800s using concrete – the material of choice for the time period -- the Fine Arts Building on the Cardinal Gibbons School campus is an important historic landmark for Baltimore, Maryland, yet the structure was in disrepair. Formerly known as St. Mary’s Industrial School, the facility served as a boarding school for young boys, including baseball great Babe Ruth. However, initial construction defects and shrinkage cracking, failure of the existing coating and drainage systems, acidic gases predominant in metropolitan areas, and the natural permeability of concrete had taken its toll. Age also was a major factor. The building was more than 100 years old, and there had been no maintenance on the facility since 1960.
With perimeter dimensions of approximately 120- by 60-feet, the three-story reinforced concrete structure has an ornamental concrete cornice. Initial inspections revealed that the cornice had severe deterioration primarily due to the existing gutter and downspout system that was non-functional. Additional deterioration was found on the concrete façade and parapet where the existing coating was no longer effective.
Recognizing the importance of restoring the concrete on this treasured landmark, several repairs were necessary to restore the structure back to its original prominence. The first step of the repair process was to chip and remove loose and deteriorated concrete to a depth of at least ¾-inch behind any exposed reinforcing steel. A high-pressure water blast was used on repair areas to clean and prepare the existing substrate. The existing steel was cleaned and prepared by the use of mechanical methods. After the cleaning was completed, the steel was coated with a corrosion inhibiting material. Supplemental reinforcing steel was added to areas where the existing steel had lost more than 20% of its cross-sectional area or as needed to provide a sound repair. In shallow areas, steel pins were added to promote bonding of the new repair material to the existing substrate.
For the façade, several types of repair were necessary including partial depth concrete repair. This was necessary in areas where the concrete had deteriorated two to three inches behind the reinforcing steel. The placement of the repair material was conducted through the combination of hand patching, form and pour, and form and pump. In several locations, extensive cracks penetrated the entire concrete wall and required full-depth repairs. A back-up form and additional reinforcing were used before the concrete repair material was poured into the prepared area. Additional repairs included the removal and replacement of all sealants for the metal window and doorframes using a premium grade urethane sealant.
The cornice was the most difficult repair. New reinforcing steel was added to the cornices due to the lack of sufficient existing steel. Plaster of Paris was used to make a mold of an existing sound section of the cornice and then fiberglass forms were developed. Several mockups were made prior to achieving the desired result, which was versatile enough to match all inconsistent field conditions of the cornice. Once the formwork was complete, the cornices, which had many intricate vertical and horizontal transitions, were poured. Upon completion, the final project cost was less than the estimated amount.
Today, because of the innovative concrete repair strategies and the effort to not only salvage but also bring new life to the structure, the building stands poised to meet the demands of tomorrow's students.
Baltimore Archdiocese, Baltimore, Maryland
General Contractor, Concrete Repair Contractor:
Structural Preservation Systems, Baltimore, Maryland