The objective of the study was to analyze the composition of mortar in order to enhance the use of milk serum and its application in earth constructions. Development of the study involved, initially, a bibliographic review and identification of dairy industry producers in the Paraiba Valley, São Paulo, with milk residue storage facilities. The next stage consisted in the preparation of three adobe molds, based on technical reproductions, of the composition of historic constructions. Subsequently, the molds were submitted to laboratory tests: preservation and compression resistance. This was followed by execution of the mortar with milk serum and bacteriological tests, anchoring, and plasticity through the application of mortar. The adobe molds were observed over a period of 15 days, with even the cracked molds shown to be useful for purposes of simulating risk situations. The technical viability analysis of the sample milk serum mortar applied to a historic construction and exposed to the natural elements for a period of 1 year revealed no deformities. After a full year of research, we found the presence of acid milk residue to be a major concern among dairy producers. Further, the difference between acid and sweet milk serum gave rise to a new challenge given the different chemical properties of the two serum types, which can alter the structure of the mortar and its efficacy. To this end, the research work was extended into 2009 with implementation of a new stage aimed at adapting Brazilian technical standards through a technical evaluation of historic mortar and the applicability of acid serum to the residue process.