ACKNOWLEDGEMENTS

The authors gratefully acknowledge the contribution of Carl Moses, associate dean of the Lehigh University College of Arts and Sciences, whose technical and petrographic studies proved to be invaluable resources throughout the course of the study. The authors would also like to express their sincere gratitude to the following professionals who assisted with the review of this article and offered invaluable expertise and insight during its development: Kate Cowing, Katherine McDowell Frey, Mark Rabinowitz, Joseph Sembrat, and Martin Weaver.

Completion of the technical study that formed the basis for this research was made possible by the support of Merle H. Ryan, deputy secretary for public works of the Commonwealth of Pennsylvania, and Robert L. Glenn, director of the Bureau of Engineering and Architecture within the Pennsylvania Department of General Services.

NOTES

1. Although considerable attention has been devoted to deterioration mechanisms for granite (Helmi 1985; Kelly 1985; Schiavon 1993; Begonhha and Braga 1996; Jones et al. 1996), a literature search conducted during the study uncovered only a few references to the use of JOS/Quintek as a means to address problematic material conditions (Zador 1992; Winkler 1994). These sources describe the JOS/Quintek process and its selection for specific programs in general terms. While certain topics involving the use of low-pressure abrasives were found (Young and Urquhart 1992), the authors were not able to locate case studies that offered comprehensive comparative information about the selection of JOS/Quintek versus other treatments.

2. The manufacturer specifically recommends a 3–5-minute dwell time, whereas this study evaluated applications that included both the recommended dwell time and dwell times up to 10 and 15 minutes. In light of the expanse of surfaces to be cleaned, the authors determined that if either cleaner were selected as the primary treatment, it would be unlikely that the contractor undertaking the work could constantly maintain a 3–5-minute dwell time in all areas. As a practical concern, it was deemed probable that even with appropriate specifications, quality standard mock-ups, and regular supervision, the treatment would dwell on some surfaces longer than the recommended dwell time at some point during construction. Therefore, the longer dwell times were examined as a component of this study to determine whether they would result in damage to the stone.

3. The application distance of 12–24 in. (30–60 cm) was deemed successful in preconstruction test panels. During construction, it became necessary to pretreat persistent, heavy crusts beneath certain overhangs with a proprietary prewash-afterwash system (SureKlean 766 Limestone and Masonry Restorer) and to reduce application distance to as little as 8 in. (20 cm). Cleaning was supervised carefully in areas where pretreatment and reduced application distances were deemed necessary.

REFERENCES

Begonhha, A. and S.Braga. 1996. Black crusts and thin black layers in granitic monuments: Their characterization and the role of air pollution. In Proceedings of the Eighth International Conference on Deterioration and Conservation of Stone, Berlin, Sept. 30–Oct.4, ed. Josef Riederer. Berlin: Moller Druck und Verlag. 371–75.

Boyer, D. W.1986. Masonry cleaning: The state of the art. Cleaning Stone and Masonry STP 935, ed. J. R.Clifton. Philadelphia: American Society for Testing and Materials.

Helmi, F. M.1985. Deterioration of some granite in Egypt. Fifth International Congress on the Deterioration and Conservation of Stone, Lausanne, France, September 25–27. Lausanne, France: Press Polytechniques. 421–29.

Heritage Studies Inc.1987. The Pennsylvania capitol: A documentary history. Harrisburg, Pa.: Capitol Preservation Committee.

Jones, M. S., P. F.O'Brien, S. J.Haneef, G. E.Thompson, G. C.Wood, and T. P.Cooper. 1996. A study of decay occurring in Leinster granite, House No. 9, Trinity College, Dublin. In Proceedings of the Eighth International Conference on Deterioration and Conservation of Stone, Berlin, Sept. 30–Oct. 4, ed. J.Riederer. Berlin: Moller Druck und Verlag. 211–21.

Kelly, J. G.1985. Geological aspects of the decay of Irish granitic building materials. Fifth International Congress on the Deterioration and Conservation of Stone, Lausanne, France, September 25–27. Lausanne: Press Polytechniques. 431–42.

Moses, C.1997. Personal and professional communications. Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pa.

Schiavon, N.1993. Microfabrics of weathered granite in urban monuments. Conservation of stone and other materials: Proceedings of the International RILEM/UNESCO Congress, UNESCO headquarters, Paris, ed. M. J.Thiel. London: E. & F. N. Spon. 271–78.

Tabasso, M. L.1988. Conservation treatments of stone. In The Deterioration and Conservation of Stone: Notes from the International Venetian Courses on Stone Restoration, ed. LorenzoLazzarini and RichardPieper. Paris: UNESCO. 271–89.

Teutonico, J. M.1988. A Laboratory Manual for Architectural Conservators. Rome: ICCROM.

Weaver, M. E.1993. Conserving buildings: A guide to techniques and materials. New York: John Wiley.

Weaver, M. E.1998. Professional communications. Martin Weaver Conservation Consultant, Nepean, Ontario.

Winkler, E. M.1994. Stone in architecture: Properties, durability. 3d ed.Notre Dame, Ind.: University of Notre Dame.

Young, M. E. and D.Urquhart. 1992. Abrasive cleaning of sandstone buildings and monuments: An experimental investigation. Proceedings of the International Conference, Edinburgh, UK, April 14–16, ed. Robin G. M.Webster. London: Donnehead Publishing. 129–40.

Zador, M.1992. Experience with cleaning and consolidating stone facades in Hungary. Proceedings of the International Conference, Edinburgh, UK, April 14–16, ed. Robin G. M.Webster. London: Donnehead Publishing. 146–52.

FURTHER READING

American Society of Civil Engineers. 1878. Transactions. New York: American Society of Civil Engineers.

Ashurst, J. and F. G.Dimes. 1990. Conservation of building and decorative stone. London: Butterworth-Heinemann.

Ashurst, J., and N.Ashurst. 1988. Practical building conservation. Vol. 1, Stone masonry. New York: Halsted Press.

Brayley, A. W.1913. History of the granite industry of New England. Boston: National Association of Granite Industries of the United States.

Building Research Establishment. 1983. Cleaning external surfaces of buildings. London: Her Majesty's Stationary Office.

Charola, A. E., C. A.Grissom, E.Erder, M. J.Wachowiak, and D.Oursler. 1996. Measuring surface roughness: Three techniques. Proceedings of the Eighth International Conference on Deterioration and Conservation of Stone, Berlin, Sept. 30–Oct. 4, ed. J.Riederer. Berlin: Moller Druck und Verlag. 1421–34.

Charola, A. E., and S. Z.Lewin. 1982. Examples of stone decay due to salt efflorescence. In Deterioration and preservation of stone: Proceedings of the 3rd International Congress, October 24–27, 1979. Rome: ICCROM. 153–64.

Ehlers, E. G. and H.Blatt. 1982. Petrology: Igneous, sedimentary, and metamorphic. New York: W. H. Freeman and Co.

Elliott, C. D.1992. Technics and architecture. Cambridge: MIT Press.

Feilden, B. M.1994. Conservation of historic buildings. Oxford: Butterworth-Heinemann.

Frey, J. C., and T. M.Noble. 1998. Masonry conservation study for the Pennsylvania capitol. Zionsville, Pa.: Noble Preservation Services.

Hurlbut, C. S., Jr.1993. Manual of mineralogy. New York: John Wiley.

Ingval, M.1996. Emerging conservation issues in consequence of cleaning Scottish historic buildings. Proceedings of the Eighth International Conference on Deterioration and Conservation of Stone, Berlin, Sept. 30–Oct. 4 1996, ed. J.Riederer. Berlin: Moller Druck und Verlag. 1405–14.

Kelly, K. L., and D. B.Judd. 1976. Color: Universal language and dictionary of names. Washington, D.C.: U.S. Department of Commerce.

Klein, C., and C. S.HurlbutJr.1977. Manual of Mineralogy. New York: John Wiley.

Laing, R. A., J.Ball, J.Scott, and M. E.Young. 2000. The implications of stone cleaning for planned building maintenance. Proceedings of the Ninth International Conference on Deterioration and Conservation of Stone, Venice, June 19–24, 2000, ed. VascoFassina. Amsterdam: Elsevier Science, B.V.813–17.

MacKenzie, W. S., and A. E.Adams. 1994. A color atlas of rocks and minerals in thin section. New York: John Wiley.

Matero, F. G.1984. A diagnostic study and treatment evaluation for the cleaning of Perry's Victory and International Peace Memorial. Bulletin of the Association for Preservation Technology16(3–4):39–51.

Matero, F. G., and A.Tagle. 1995. Cleaning, iron stain removal, and surface repair of architectural marble and crystalline limestones: The Metropolitan Club. Journal of the American Institute for Conservation34(1):49–68.

Menhert, K. R.1968. Migmatites and the origin of granitic rocks. New York: Elsevier.

Pirsson, L.1926. Rocks and rock minerals. New York: John Wiley.

Rock of Ages Corp.The Barre granite industry. Barre, Vt.

Sather, K. M.1990. Granite deterioration in the graveyard of Saint James the Less, Philadelphia. Master's thesis, graduate program in historic preservation, University of Pennsylvania.

Urquhart, D. C. M., M.Jones, J.MacDonald, K.Nicholson, and M. E.Young. Effects of stonecleaning on granite buildings and monuments: Report to Historic Scotland, Scottish Enterprise and Grampian Enterprise, 1996. www2.rgu.ac.uk/schools/mcrg/migran.htm (accessed 1998; March 12, 2003).

Van Diver, B. B.1987. Roadside geology of Vermont and New Hampshire. Missoula, Mont.: Mountain Press.

Winkler, E. M.1980. Historical implications in the complexity of destructive salt weathering: Cleopatra's Needle, New York. Bulletin of the Association for Preservation Technology12(2):94–102.

Young, M. E.1993. Stonecleaning of granite buildings and monuments: The use of colour measurements in stonecleaning trials. Conservation Science in the UK. Preprints of the meetings held in Glasgow, May, ed. N. H.Tennent. London: James & James Science Publishers. 20–28.

SOURCES OF MATERIALS AND STANDARDS

Thomann-Hanry Inc. 575 Madison Ave., 25th floor New York, N.Y. 10022 (212) 755-5550

Gretag Macbeth 617 Little Britain Rd., Suite 102 New Windsor, N.Y. 12553-6148 (800) 622-2384

Quintek Corporation P.O. Box 777 Virgil, Ontario, Canada L0S 1T0 (800) 567-0053

Note: Quintek Corporation supplies both equipment and microabrasive media manufactured by Universal Ground Cullet (M1035, M1040) and Specialty Minerals Inc. (dolomite)

RILEM 157 Rue des Blains F-92220 Bagneaux, France 33 1 45 36 1020

PROSOCO Inc. 3741 Greenway Circle Lawrence, Kans. 66046 (800) 255-4255

AUTHOR INFORMATION

J. CHRISTOPHER FREY earned a B.A. in history from Dartmouth College in 1992 and an M.S. in historic preservation from the University of Pennsylvania in 1997. He currently serves as an associate with Noble Preservation Services of Zionsville, Pennsylvania, where he focuses on the analysis and conservation of historic building materials. In addition to being listed as a professional associate with AIC in 2001, his professional and academic r�sum� includes experience with Historic Charleston Foundation (1996), University of Pennsylvania Field Conservation Program with the National Park Service (1996), the Frank Lloyd Wright Building Conservancy (1996), Fairmount Park Historic Preservation Trust (1995–97), and the Museum of New Hampshire History (1994–95). Address: Noble Preservation Services, 10 Log House Rd., Zionsville, Pa. 18092

TIMOTHY NOBLE received a B.A. from Pennsylvania State University in 1974 and earned an M.S. in historic preservation from the University of Pennsylvania in 1983. He is listed as a professional associate with AIC. Having served as president of Noble Preservation Services since 1992, he manages and supervises projects relating to architectural conservation and the analysis of historic building materials. Prior to establishing his own private practice, he was principal and president of Clio Group Inc. (1983–92) and director of Stenton (historic site, 1991–92). Address as for Frey.