Following my own presentation in this session, I had the privilege of listening to my colleagues at Columbia University and the University of Texas-Austin discuss their research on architectural conservation material issues.
Sarah Sher (Columbia) exposed the design theory behind soiling on Marcel Breuer’s buildings through conducting an elaborate study of his personal writings and lectures. She challenged conservators that approach Breuer’s structures to view the soiling as significant to its overall design aesthetic, because it was intentional. For Breuer, reinforced concrete was the ideal material- requiring little to no cleaning (as opposed to its glass/steel counterpart), and that soiling in fact enhanced the aesthetic of the architecture “to aid in the process of aging.” In the section of her presentation entitled “Designing the Aging Process,” Sher focused her discussion on Breuer’s Cleveland Trust tower. Breuer anticipated heavy soiling on the structure, quoting the effects of polluted Cleveland air. He designed for this effect, which he believed allowed shadowing and depth of the surface. Sher ended her talk with Riegl’s conception of age value, and the questions that modernist pose for conservation interventions. With a fascinating talk, Sher introduced research into a field that will need to be expanded and better understood as we are increasingly working on modernist and Brutalist structures.
Sarah Caitlin von Hedemann (Columbia) presented her thesis research on current cleaning formulations for removing biogrowth on stone, utilizing a newly manufactured Prestor gel. She utilized laboratory testing, as well as field tests on sites around the city of New York, including 1- Wallace limestone (facade of the Metropolitan Museum of Art), 2- Indiana limestone (exterior of The Cloisters museum), 3- Texas limestone (Bronx Victory Memorial), 4-Tuckahoe marble ( Lagrange Terrace, Delbarton School), and 5- Carrara marble (Portrait Bust, Delbarton School) –if I mislabeled or misunderstood any of these stone types, please comment to correct me! Utilizing analytical tests ranging from XRD, SEM-EDS, FTIR and GC-MS, she tested the products’ effectiveness and the presence of residues left by the cleaners. von Hedemann concluded with her recommendations: Prestor gel should be used for less porous stone, as it had atendency remove porous stone surfaces, CB-4 requires more research but was overall ineffective and left larger residues, BioKlean was successful but this might be due to its 2-step process and it is considered very agressive and alkaline, and D-2 and BioWash had average cleaning capability.
Payal Vora (UT-Austin) studied as a Materials Science engineer in her undergraduate education, and became interested in preservation efforts following natural disasters. Her thesis is an extension of this interest, as she conducted a study of masonry cleaners for Fort Livingston, LA following the 2010 Gulf coast oil spill. The fort, located on Grand Terre island is the only occupied barrier island in Louisiana, and has been greatly affected by the spill due to erosion issues that allow parts of the fort to remain underwater. The unprecedented contamination of the spill, required a technical study to guide conservation efforts, and this was spear-headed by NCPTT and UT’s Architectural Conservation Laboratory. Unable to remove original material from the fort, NCPTT provided contemporaneous brick (from a demolished early 1900s home) as samples for Vora’s study. Developing her experimental design,Vora prepared her samples according to ASTM C-67-09, she developed a method for soiling the samples, and conducted artificial weathering with an Atlas C-4000 Xenon Arc Weather-oMeter on the brick Q-series. On the U-Series, samples were unweathered, but placed in an oven for 8-10 hours to ensure samples were dry prior to cleaning. Cleaners were chosen from the National Remediation Plan’s list of approved cleaners for the Gulf Coast spill- the 6 final choices were Petro-Clean, Cytosol, SC-1000, Gold Crew, De-Solv-It Industrial Form and De-Solv-It APC. Cleaning was evaluated using telecolorimetry and a visual inspection survey. Responding to a national crisis, the project represents an important effort in disaster relief for historic structures.
It was a pleasure to hear about the incredible work being done by emerging professionals in this field!