Architectural Preservation at Boston College Campus: a Systematic Approach”

IFMA Facility Fusion 2011 8.06 “Architectural Preservation at Boston College Campus: A Systematic Approach”

Wendall C. Kalsow, AIA, McGinley Kalsow & Associates Ivan Myjer, Building and Monument Conservation Evan Kopelson, Vertical Access LLC / TPAS LLC

Online Conference Proceedings Submittal

Introduction Founded in 1863, Boston College is a Jesuit institution of higher learning, originally located in Bostonʼs South End. In 1907, Father Thomas Gasson, who had recently become BCʼs president, decided that the cramped, urban surroundings of the location were unsuited to the expansion of the college, and started the process of moving the campus to Chestnut Hill, six miles west of Boston. Charles Donagh Maginnis of the Boston architectural firm of Maginnis and Walsh won an architectural competition for the master plan of the new campus, Design Competition Winning Vision of Boston College Maginnis & Walsh (1909) which included twenty buildings in an English Collegiate Gothic style. By 1909, construction of the first building, originally known as “Recitation Hall,” then the “Tower Building,” now “Gasson Hall” had commenced. Completed in 1913 the main building stood as the only completed portion of the campus plan for some years, until funds were raised to construct additional buildings. Among the other early buildings forming the Chestnut Hill campus of Boston College are St. Maryʼs Hall (1917), Bapst Library (1922) and Devlin Hall (1924). Lyons Hall, the fifth building included in the current study, was constructed in 1951.

Since 2006, McGinley Kalsow & Associates, Building and Monument Conservation and Vertical Access have been working with the Capital Projects Management Department of Boston College to investigate, document and design repairs to the historic campus buildings. The project team has taken a systematic approach involving hands- on investigation, detailed documentation of existing conditions, thorough analysis of collected data, and preparation of comprehensive treatment recommendations and construction documents. Beginning with the hands-on investigation of Postcard ca.1913 – Gasson Hall

1 Gasson Hall in 2006 and continuing with the documentation and assessment of St. Mary's Hall, Bapst and Burns Library, Devlin Hall and Lyons Hall in 2007, the project team has collected detailed information on the existing conditions of the group of buildings at the central campus area of Boston College. Conditions of the cast stone, limestone, puddingstone and granite masonry of these buildings were mapped out unit- by-unit using TPAS, a direct digital documentation system. The data was then evaluated to prepare treatment recommendations and assist Boston College in prioritizing future capital repair projects for the historic buildings. The first project undertaken was the restoration of the landmark Gasson Hall at the center of the campus.

The buildings designed as part of the first phase of construction for the campus are masonry buildings with puddingstone used for the field of the exterior walls and a second material used for trim and ornament. Puddingstone is a sedimentary stone, but one without well-defined bedding planes. Structurally, it is more of a conglomerate with a variety of large inclusions in a relatively hard matrix. It was quarried locally, and commonly used in stone foundations and walls in the Boston area. At Gasson Hall and St. Maryʼs Gasson Hall – Construction Photo ca. 1912 Hall, cast stone is used for the decorative units, including the quoins, corner piers, window surrounds and tracery. Some of the cast stone had a rilled tooling pattern that would have given the appearance of natural stone. Limestone was used for trim and ornament of Bapst Library and Devlin Hall, instead of cast stone, and is the primary exterior material at Lyons Hall.

Investigation and Documentation In 2006, the Capital Planning and Engineering Department of Boston College requested proposals for architecture/engineering services for the Restoration of Gasson Hall Exterior Façades project from an invited group of consultants. The design contract was awarded to a project team led by McGinley Kalsow & Associates with Building and Monument Conservation, LeMessurier Consultants Structural Engineers and Vertical Access. The first part of the Gasson Hall project entailed a hands-on investigation of the building to document existing conditions. A combination of industrial rope access and aerial platforms (boom lifts) was used for the hands-on survey. At the tower, VA technicians used industrial rope access to perform the up-close examination. McGinley Kalsow and Building and Monument Conservation used aerial platforms to survey the lower portion of the building.

One of the tools used during the investigation of the tower was live-feed video. At the outset of the investigation, VA technicians surveying the exterior tower used a hand-held video camera connected to a monitor at the base of the tower to review conditions with the entire project team. Using two-way radios, the project team was able to ask questions of the VA technician operating the camera and clarify findings about specific conditions. In this way, the entire project team could gain a consensus understanding of the issues affecting the deterioration of the materials, structural condition and ultimately the restoration of the building.

The project team used tablet computers and the Tablet PC Annotation System (TPASTM) to record existing conditions at both the tower and base of Gasson Hall. Vertical Access developed the Tablet PC Annotation System (TPAS) to input annotations, graphics and numerical data directly into AutoCAD, on site, using tablet computers and digital cameras. Direct digital documentation eliminates the two-step data entry process traditionally used during condition surveys with paper drawings and pen annotations, adding efficiency to the reporting process and eliminating transcription errors during redrafting.

Working within the AutoCAD program, TPAS employs standard commands in conjunction with customized programming. Among the features employed using TPAS that are native to AutoCAD are block libraries, blocks with attribute tags, AutoCAD design center, selective display of layers and attribute extraction to spreadsheet or database programs. Custom programming provides automatic calculations of the lengths and areas of conditions drawn and inserted into the AutoCAD drawing and on-site naming and hyperlinking of digital photographs to automate the process of photo capture and cataloging. Vertical Access Technicians Rappelling Down the Façade of Gasson Hall TPAS is a tool used not only for collecting data in the field, but also for managing and organizing the data in the office. All condition information in the AutoCAD drawing is managed by layer to facilitate the control and visual display of information. This tool can help with the interpretation of condition drawings, identification of fault patterns and assessment of building conditions. TPAS also allows for the export of all numerical condition information into a generic data file format that can be imported into any spreadsheet or database program for analysis of conditions, calculation of take-offs, creation of cost estimates for project scoping and development of phasing or scheduling scenarios.

The investigation of Gasson Hall served as a model for work that was undertaken the following summer to investigate and document the existing conditions of four additional buildings on Boston Collegeʼs Chestnut Hill campus. In each case, the investigation was performed using a hands- on approach. At Bapst Library and St. Maryʼs Hall, a combination of rope access and aerial platforms were used for the close-up examination of existing conditions. At Devlin and Lyons Halls, aerial platforms were used for the hands-on investigation. In all cases, close interaction among members of the project team and Photograph of core drilled hole showing partial deterioration documentation of existing conditions using of cast stone ¾” from the face of the stone TPAS were integral to the investigation.

3 Analysis and Assessment The building in most urgent need of repair was Gasson Hall. The survey data collected by the team and documented using TPAS, was analyzed by the design team in order to identify patterns of masonry deterioration as well as to evaluate the efficacy of prior repairs to the cast stone trim units. The analysis determined that the rate of deterioration in the cast stone had advanced rapidly over the past 35 years. Our analysis also indicated that, since the two prior restoration efforts had not succeeded in arresting the cast stone deterioration, there was a very good possibility that the problem with the cast stone was the result of an inherent fault. To test our hypothesis, cores were taken from units that were weathered but still sound as well as from units that were severely deteriorated. Following a visual examination, the cores were sent to a lab for petrographic analysis and reverse engineering of the mix. There are several factors resulting from the fabrication of early 20th century cast stone that can produce systemic failure of the units. Among these are alkali silica reaction, loss of carbonation and a susceptibility to freeze-thaw damage resulting from a lack of air entrainment in the mix. It was this last factor that John Walsh, a petrographer, currently with Highbridge Materials Consulting, identified as the principal cause of the ongoing cast stone failure. Secondary causes included cracking caused by the corrosion and expansion of uncoated steel reinforcement and anchors. Microscopic examination of cast stone confirmed that cast The physical properties of the original cast stone deterioration was widespread and would become stone and puddingstone dramatically progressively worse over the next decade impacted their durability.

Knowing that there are no treatments that can compensate for the lack of air entrainment in the original mix led the design team to recommend 100% replacement of the original cast stone units. The recommendation was accepted by Boston College with the mandate that the replacement units have a service life of at least 100 years. In developing the specifications for the replacement cast stone units, the design team evaluated the industry standards for pre-cast concrete, cast stone and poured in place concrete. The specifications for Gasson Hall stipulated that the new units should be "measurable slump, wet poured cast stone" and all reinforcement and anchors should be stainless steel. In order to avoid the previous problem of the cast stone weathering to black from the exposure of the large aggregate, a light colored aggregate was specified for the new units.

As quality control measures, the air content, slump, cement to water ratio, compressive strength and water absorption have been monitored and recorded by the fabricator and tested for compliance with the specifications by an independent testing lab retained by Boston College.

One of the principal difficulties in replicating the 11 thousand plus cast stone units has been in recreating the appearance of the original cast stone. The original 1913 cast stone was fabricated to resemble carved and tooled Indiana limestone. All of the flat surfaces had a 'six line to the inch, rilled finish" that over time has weathered away. In order to recreate the original tooling and surface texture, weathered but sound original units were resurfaced with a white resin that was then shaped and tooled to recreate the original

4 tooling. These units were then used as patterns to create the rubber molds into which the cement was poured.

Restoration Design and Construction Since deterioration was more advanced on the walls of the tower than at the four floors of classrooms and offices, Boston College decided to undertake this major restoration project in two phases. In 2007 and 2008, Phase I restored the tower and selected 2nd and 3rd floor areas. This work was completed while the building was fully occupied. After Commencement in 2010, Gasson Hall was vacated so that all sections of the building could be worked on at the same time. This decision to vacate the entire building reduced the construction time period from 27 months to 15 months, saving general conditions and construction costs. By the projectʼs completion, over 95 percent of the cast stone will have been replaced. Conversely, less than 0.5 percent of the puddingstone will have been replaced.

During both phases over 8,000 pieces of cast stone will be replaced with more than 1,000 unique shapes. Each piece of cast stone was numbered and drawn on elevations with each unique shape being detailed on the contract documents used to competitively bid each phase. The weight of individual pieces of cast stone ranges from 35 pounds to almost 5,000 pounds with a total weight of over 3.7 million pounds. The complexity of the restoration work required a very demanding level of craftsmanship and management skills. Phase I, which was predominantly masonry work, was completed by general contractor Phoenix Bay State Construction. In addition to masonry work, Phase II included extensive accessibility improvement, window replacement, landscaping, new fire protection and sprinkler systems, as well as upgrades to classrooms, offices and public areas. Shawmut Design and Construction is the general contractor for Phase II, while Grande Masonry is performing all the masonry work. For both phases, Béton Préfabriqué (BPDL) of Quebec is fabricating the cast stone.

Because of the variety and complexity of the original cast stone shapes, each unique shape was removed from the building and sent to BPDL to assist in the replication of the cast stone. Several different techniques were used in the preparation of patterns and molds.

Original Weathered Cast Stone New Cast Stone Unit

For most of the building, cast stone was used for a large variety of decorative elements including quoins, window surrounds, string courses, the water table and coping stone, while the field was constructed of puddingstone. The exception to this general rule is the top of the 200-foot tall tower, of which the top 50 feet is constructed only of cast stone. This design and the condition of the original cast stone necessitated the removal of the top 50 feet of the tower, including the tower roof and steel beams.

Phase II will provide four fully accessible entrance to Gasson Hall and improve accessibility throughout the building. This phase will be completed by August 15, 2011, allowing the building to be fully occupied when classes begin after Labor Day.

Completed Tower

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