Overcladding for Performance
These solutions are complicated and challenging to explain to stakeholders who are not building professionals. But once the project team has the confidence of decision-makers, a community will be able to enjoy a piece of its legacy, an iconic architectural landmark, for decades to come. After all, in addition to providing the setting for teaching and learning, school buildings in many cities and towns are frequently places where residents of those communities go to vote, attend meetings of various kinds, gather for social and cultural events, and participate in other types of civic engagement.
Masonry strengthening, façade overcladding, and targeted expansions represent cost-effective approaches to making the most of existing K-12 facilities, university buildings, civic structures, and older commercial and residential architecture. The approach can benefit a wide and diverse group of users. They can also contribute to improved neighborhood cohesion, helping to celebrate and build upon the legacy of each existing or historic building.
Case Studies: Urban Public Schools
These conditions may be seen in older school buildings around the country. Unfortunately, the combined forces of time, climate, and lagging maintenance can leave school districts’ facilities teams with significant, and often unexpected challenges. Schools typically age faster than funding to fix them is allocated.
For some municipalities, this leads to a continuing cycle of each newly composed school board deferring addressing the problem to the next one, while student populations change and expand, and the natural wear-and-tear process accelerates. For officials to address the deleterious effects of time, weather, and full occupancy on masonry school buildings, overcladding has emerged as a valuable strategy. The relatively simple, energy-conscious façade upgrades can be accompanied by replacements of outdated, thermally inefficient windows. As many older, masonry load-bearing walls are today degrading considerably, now porous and leaking, the damage to brickwork, window openings, and interior plaster walls can be severe.
Complicating the rehabilitative projects are issues mandated by building, energy, and life-safety codes. Replacing masonry is typically not going to be an option—and even when it is possible, it can lead to an unappealing patchwork look that inspires little confidence in the community the school serves. Instead, overcladding wraps the entire masonry façade with a new, performative outer layer that allows the introduction of more modern architectural thinking to older schools.
The following example is one approach to façade over-cladding at P.S. 73 in Brooklyn, New York. Built in the late 19th century, the aging brick façade of this remarkable school building had naturally begun to weaken after more than 100 years of service. A site visit by architects revealed the original copper cornices were deteriorated and gone, and pieces of brick and mortar were working their way loose, presenting a potential hazard to passersby. These were red flags, and a project team began to address the issue.
To rehabilitate the structure, the designers working with School Construction Authority (SCA), or New York City recreated some of the original architectural components, matching them exactly to produce a cohesive look that honors the familiar and locally beloved school. Apart from these cosmetic approaches, a considerable amount of effort went into the use of grout injection technology to strengthen the aging masonry from within. Filling every void and hairline crack, the hydraulic lime grout has enhanced the structural integrity and prevented future damage from penetration by moisture.
In another example, P.S. 88 in Queens, New York, a 1907 facility required a means for improving the energy performance of its enclosure while returning distressed and discolored architectural details to some measure of their former glory. Over the decades some architectural features had been removed, including the original parapets, cornices, and other neoclassical detail. At the same time the rehabilitation project would have to address the severe moisture damage to the academic spaces inside revealed by a site survey, to protect students and staff from mold and other moisture-related health hazards. The project team tested exterior walls to determine the amount of water ingress and relative structural integrity, inspecting the headers, wood window jambs, interior clay tile, and plaster finish.
The building was determined to be an ideal candidate for façade overcladding. The existing wall could be treated with an exterior parge coat and moisture barrier, followed by a drainage mat. Last, a new brickface would be installed in a color and style to match the original masonry deemed strong enough to support the addition. The overclad stabilized the school building and extended its service life. At the base, cast stone masonry replicas preserved the building profile, and lookalike cast-stone headers are installed over existing, rehabilitated steel. Durable windowsill upgrades include flashing and sub-sill pans, and the parapet, stripped of its original character over time, has been rebuilt with concrete curb and hung with an ornamental cornice composed of glass fiber-reinforced concrete (GFRC).
Albert Aronov, AIA, is a partner with RKTB Architects, P.C., where he specializes in building restoration as well as new construction in the academic, residential, and commercial sectors. Aronov has led his firm’s education studio since 2004.
