Another historic project where materi- als were carefully selected and specifi ed for their appropriateness is Eastern Market, also in Washington. Located on Capitol Hill, Eastern Market is a thriving center of economic and social activity. The market’s original South Hall was designed by Adolf Cluss, one of Washington’s most infl uen- tial architects, and constructed in 1871. The market was expanded in 1906 by architect Snowden Ashford, creating the Center Hall and North Hall. In 2005, Quinn Evans Architects began designing a comprehensive rehabilitation for this city-owned landmark, which had last been restored in the 1970s. On April 30, 2007, before construction work began, the market was devastated by fi re, requiring ad- ditional and substantial restoration of the building. Quinn Evans Architects designed the restoration, which included a new roof, masonry repairs, new building systems, introduction of air conditioning and auto- matic fi re-suppression systems. The 1970s restoration had replaced the
original galvanized cornice with a stainless- steel cornice, matching the historic profi les. Working from the 1970s drawings and elements remaining after the fi re, Quinn Evans Architects specifi ed Revere Copper’s TCS II, a zinc-tin-coated stainless steel as the new material for the cornice. One of the advantages of the zinc-tin coating is its abil- ity to take paint, which allowed for a more accurate “sand fi nish,” intended to mimic the appearance of stone, to be applied. The TCS II product also was used for the decorative chimneys and acroteria elements on the roof that were restored based on historic photos. Much of the roofi ng slate was deteriorat-
ed or heavily damaged by the fi re, so the de- cision was made to replace the slate. Some review boards permit faux slate products,
but, for a building as signifi cant as Eastern Market, replacement in-kind was required (and desired for its long-term performance). The slate shingles installed at Eastern Market were Del Carmen slate from Spain, a product available in the U.S. from SSQ Group. This product was a good visual match with the historic slate and more affordable and readily available than domestic sources. As a result of the fi re, the iron roof
trusses in the South Hall were heavily dam- aged and compromised—deformed—by the intensity of the heat. To maintain the overall interior appearance of the historic market space, a series of new trusses were designed to closely match the historic truss design. Wrought-iron elements were fabricated in steel, and the compression strut member, originally made of cast iron, was refabricated with cast iron for the new trusses that were installed in between each historic truss that was retained in place. Careful coordination with the iron fabrica- tor was necessary to ensure the new strut members were good matches to the historic strut members being replicated in terms of size, profi le and texture. Once painted and installed, the South Hall at Eastern Market was restored to its original grandeur.
No two historic preservation projects are the same, and most projects require a balance between traditional and contempo- rary materials. When traditional materials are no longer available, careful attention to material selection is important to ensure the materials planned for use in a project are compatible, appropriate and can be approved by reviewing agencies. A small amount of research and input from pres- ervation professionals can go a long way toward proper specifi cation of products for your next historic building project.
Historic Preservation Material Options
On the original section of the National Academy of Sciences building, the existing windows were stripped and repainted with a high-performance coating, and weather strip- ping was added. Glazing film on the window’s interior face improves energy performance.