February 2003

Challenges of Boston Public Library Renovation Creates Innovative Opportunities

"A palace for the people" is how architect Charles Follen McKim described his stunning McKim Building at the Boston Public Library. Completed in 1895, this National Historic Landmark indeed boasts palatial beauty and history. Yet as time enhances the McKim Building's majesty, time also threatens its beauty and functionality. Heeling the wounds inflicted by time continually provides architects and contractors' the opportunity to be innovative in their respective roles. The architecture firm of Shepley Bulfinch Richardson and Abbot (SBRA) is joined again by general contractors Lee Kennedy Co., Inc. (LKCo) to perform another phase of the multi-phased Boston Public Library renovation and restoration. Both firms completed the 1997 restoration of the library's grand reading room known as Bates Hall, as well as other areas, inside the McKim Building.

The current phase includes three of the most significant spaces in the building: the Sargent Gallery, Abbey Room and the Trustees Room. Although these ornately decorated rooms share a historical significance as part of the larger ensemble, each space is quite distinct in character, presenting different design challenges in its restoration. It is worth noting that there are a variety of design approaches (professionally called "treatments") for historic structures, which range from Restoration to Renovation to Rehabilitation.

As the term implies, restoration takes an academic approach, restoring the space or architectural elements to a specific time period based on documentary research and analysis of historic materials. These approaches are all outlined by the U.S. Secretary of the Interior's Standards established for historic properties. Renovation, on the other hand, is a comparatively more radical treatment that involves stripping the existing interior and creating an altogether new use for the space. Rehabilitation is an intermediary treatment between restoration and renovation whereby character-defining elements of a space are identified and the intent is to maximize the use by restoration or preservation. In this case, the space may give way to more modern aesthetic elements such as flooring materials or lighting fixtures.

The Sargent Gallery
The Sargent Gallery is the strongest and most successful example of Charles McKim's intimate collaboration with artist John Singer Sargent. As a result, Sargent was given creative control of not just the surfaces he was to adorn, but the entire room and its décor, fixtures and appurtenances. While this creative collaboration resulted in one of the most compelling civic spaces of its day--arguably to this day, it presents a complex array of challenges that must be met by today's restoration project team, from the technical and aesthetic to the contractual. The primary design objective is to faithfully return the room to its appearance as Sargent left it. A successful restoration of this room is also dependent on a collaborative approach, however, unlike the original collaboration between architect and artist, the room's restoration requires the collaboration of many restoration specialists and craftspeople. The work must integrate the restoration aspects of decorative paint, fine art murals and lighting to name a few, as well as the Library's contemporary needs for safety, lighting and environment.

The Abbey Room
Collaborating with artist Edwin Austin Abbey, Charles McKim provided a strong architectural framework within which Abbey proceeded to depict the story of the Quest for the Holy Grail. In this room, the restoration objective is to return it to its original appearance as much as is possible, while at the same time, the design needs to weave into and behind the historic fabric the necessary modern systems and services that allow the room to remain a vital and functional component of the Boston Public Library's contemporary programs. The creative design challenge is significant in the Abbey Room, because it must support multiple uses in the future, and the requirements for environment and lighting change with each use. Early exploratory work in the Abbey Room confirmed that the marble floor had several areas in need of being lifted and re-set, and that the conduit necessary to distribute a flexible arrangement of power to the room could be accommodated seamlessly within the interstitial space of the setting bed between historic stone pavers and the substrate approximately three inches below.

The Trustees Room
One of many hidden treasure of the McKim Building, the original Trustees Room represents a gorgeous re-interpretation and re-construction of the antique interiors of a Parisian hotel. In this space Charles McKim displays his mastery of procuring architectural components, already historic in 1895, and knitting them together in an all-new creation uniquely tailored to suit the architectural aspirations of his client. The design challenges are many: as the antiquities take on an added level of significance, and as the materials added by McKim to complete the room were visually seamless at the time, yet these have all aged differently. Architectural conservation treatments must respond to the technical needs of each different material in its repair, however, the ensemble must be aesthetically considered as a whole.

According to William Barry, AIA, a Senior Associate at SBRA and member of an extensive BPL design team, these three rooms undergoing restoration present several challenges that have offered opportunities to apply innovative design applications and techniques at both the design and construction phase. The partnership forged between SBRA and LKCo has resulted in a successful preplanning process that has ensured a smooth exchange between design and construction.

One of the principal challenges--and an important first step for the project team early on in the project--was to perform exploratory investigations. The intent of such exploration is to minimize the risk of unforeseen problems once the walls, ceilings and floors are opened up and restoration is underway. The scope of early physical explorations is often limited, so an important next step is a more thorough program at the onset of construction that more fully opens up the building fabric to explore hidden conditions.

In this process, LKCo, SBRA and the client must work together closely so that the client can make informed decisions regarding the extent of explorations given budget and time. With the understanding that there will inevitably be surprises in such a complex restoration project, the exploration as a tool, helps the client proceed with the restoration, confident that its investment in the project is justified.

While each of the three rooms present varying physical conditions, the architect and general contractor anticipate that all rooms will present a similar challenge that requires an innovative application of new technique and materials: how to incorporate contemporary services while meticulously restoring the historic interior decorative detail. In other words, how to convert antique lighting fixtures so they would meet current standards for light levels, upgrade the existing HVAC system and install wiring/cables to accommodate the new technologies within the interstitial spaces beneath the flooring, in the walls and above the ceiling. During the Bates Hall project, SBRA and LKCo collaborated successfully and applied similar techniques in the flooring.

In the field, once construction has started, the contractor's creative input can be critical to success. For the Bates Hall project, the plan for installing computer cables was to lift up the central marble runway that traversed the length of the reading room, remove the grout, and place the computer cables in the hollowed out, interstitial space beneath. "To our surprise, the stone proved to be intractable, presenting the likelihood of a high loss of historical material," said Barry. "LKCo and terrazzo consultant De Paoli Mosaic Company of Roxbury provided the elegant solution. Although the terrazzo on either side of the marble runway would be a challenge to match if it were removed, it was less historically significant. We left the marble intact, and De Paoli was able to recreate beautifully matched new flooring that seamlessly filled the old terrazzo."

The current project presents similar challenges in concealing modern elements behind historic walls. In order to perform HVAC work in the attic, for example, LKCo has taken careful measures to accommodate the space limitations of working above the barrel vaulted ceiling of Bates Hall. "This building is one of the oldest landmarks in the City of Boston so you could imagine trying to install new mechanical equipment behind these walls," comments LKCo Project Manager Salvatore Sachetta.

It is interesting to note that restoring a building constructed in the 1950s can present more of a challenge in retrofitting it to meet 21st century needs. Unlike 19th-century construction, the interior and exterior walls and flooring were often built without interstitial spaces behind walls and above ceilings where upgraded wiring or other utilities could be neatly hidden.

On the flip side of dealing with modern additions, the contractor must have an in-depth knowledge of the existing historic material-and its co-existence with modern construction methods. The 18th century Yorkshire sandstone used for the walls, floor, stairs, and balusters in the Sargent Gallery is very soft and has very soft profiles. As a result, Lee Kennedy Co., Inc. utilized a new micro abrasive cleaning technique to clean the sandstone. The process incorporates microscopic glass beads that are shot out of a pressurized hamper mixed with water at 30 lbs of pressure. The soft stone could have been damaged if not cleaned correctly.

Also imperative to any restoration is performing work to fix one aspect of a building without the risk of damaging another. Sachetta notes, "The largest obstacle has been temporary protection to a multitude of historic murals, objects, and finishes during normal construction upgrades, such as electrical, mechanical, plumbing, and fire protection." While performing the micro abrasive cleaning to the Sargent Gallery, a temporary tent was erected to encapsulate construction workers and eliminate disturbance to adjacent areas. The same case holds true in the Abbey room. "We had to protect the murals above while performing the woodwork restoration to the perimeter raised wood panels, columns, and benches," Sachetta adds.

To a further extent, architects and contractors must be careful not to create one solution only to risk creating another problem. To return the Sargent Gallery to its intended appearance, for example, three very large skylights that were covered for years have now been opened to the natural light. This not only achieves the original look of the gallery, but will prevent future damage to the murals caused by fluorescent lighting. However, sunshades that operate on light sensitive photo-cells were incorporated into the design to prevent UV damage to the murals.

The incorporation of old and new is an integral element of the project. New MEP systems and a new elevator will be installed. Additionally, the existing book conveyer system, which transports books from the historic McKim Building to the Johnson Building, will be replaced with a faster computerized system. All of the existing historic light fixtures have been removed and shipped out to an historical light conservator. The lights will be restored and reinstalled to their original state.

From the initial exploratory investigation to the exacting details of the restoration process, challenges can inspire innovative application and creative use of new and existing design and construction techniques. These, in turn, can contribute to the success of the next restoration opportunity.