Introduction. Interdisciplinary research is a most relevant issue in science and education. The integration of intellectual resources with research and production infrastructure is acknowledged as the main goal of interdisciplinary research in the international practice. The main (analytical) part. The authors propose the following methodological approach to the study, based on the distribution of interdisciplinary methods into groups by the scale of the research subject (material). In this case, the studies have the following levels: microlevel, supramolecular level, material research, design research. The paper presents research methods used at each of these levels. The co-authors propose to optimize the study of performance characteristics of building materials and fire retardants through the use of a compatibility chart with regard for the study levels and the analysis of methods of experimental research at each level. Using a compatibility chart. The methodology of the study. A research into the fire retardant efficiency of esters of phosphoric acid, used to modify wood, was selected as a practical example for compatibility diagrams. The project encompasses a number of methods applicable to compatibility charts: the method of elemental analysis, the Gibbs energy assessment method, the sample surface assessment method, the electron microscopy method, methods of assessing fire-hazardous characteristics of wood, the water sorption method, strength and biosecurity assessment methods. Conclusions. The co-authors first proposed an algorithm for generalizing the empirical data on mechanochemical characteristics of materials using interdisciplinary methods in the form of a compatibility chart. This methodology optimizes research into any composite materials though it preserves targeted research methods and eliminates impractical and concomitant experimental studies, thus, reducing labour costs and environmental impacts.