AIC’s 40th Annual Meeting, Architecture Session: “Gelatin as an Adhesive for the Reattachment of Decorative Earthen Surface Finishes”, May 11, 2012

Emily Aloiz presented a recent treatment investigation to address blistering and delamination of earthen finishes at Mesa Verde National Park in Colorado.  Her study continues the work begun in 1994 at this site by Professor Frank Matero and the graduate students of the University of Pennsylvania program in Historic Preservation. ( ) The need to identify an adhesive which would re-adhere delaminating earthen finishes within the alcove sites of the park was guided by a desire to be respectful of the site’s Native American culture by choosing a natural product.   Other parameters which were identified included: practical, inexpensive, non-toxic; durability in an outdoor environment and compatible with sandstone and earthen materials; re-establishes adhesion; retreatable; and versatile.  Laboratory tests were conducted on a group of proxy samples using a food-grade gelatin as well as the gelatin with the addition of glycerine.  Emily carefully laid out the methodology followed during these tests to analyze bond strength, changes due to freeze/thaw and wet/dry cycles and humidity fluctuations.  Because the gelatin is organic, biodeterioration was also a concern and was addressed by placing petri dishes of the gelatin solutions at the site as a monitoring system.  Once laboratory tests confirmed the feasibility of the use of these gelatin solutions, treatment was carried out in situ by syringe injection between the earthen finish and the substrate.  Where there was carbon soot present on the surface, it was first treated by applying cyclododecane as a spray.