This thesis comes out of years of work beginning in 1994 undertaken by Frank Matero and the University of Pennsylvania to stabilize the earthen surface finishes of Mesa Verde National Park in Southwestern Colorado. The aim of this research is to better understand the performance and deterioration mechanisms for gelatin treatments used to reattach earthen plasters and washes. Threats to the treatment method include biodeterioration and failure due to wet-dry cycles and humidity fluctuations. The adhesive’s durability to these weathering phenomena was researched and evaluated through testing proxy samples in the Architectural Conservation Laboratory of the University of Pennsylvania. (All tests conducted are listed in the Testing Matrix: Appendix A) The goals of this project were to: Understand the properties, manufacturing process, history and use in conservation of gelatin as an adhesive and identify its greatest vulnerabilities Evaluate the bond strength and wet-dry and freeze-thaw deterioration that can occur once the gelatin treatment has been applied to earthen finishes in formulations that include glycerin as an additive Determine the most effective method of testing a conservation material’s bioreceptivity and apply it to gelatin Synthesize new data and data from previous research to establish climatic conditions for optimal performance of gelatin at Mesa Verde and other earthen sites