Two distinct sections of research are presented in this thesis. The first section summarizes research conducted on laboratory-built floors. Floors were built and tested to determine the plywood contribution to increasing the bending stiffness, number of joists effective in resisting applied load, and calculation of fundamental frequency. The second section summarizes research conducted on in-situ floors. Procedures were developed to numerically integrate acceleration and velocity data to obtain displacement values. Tests were conducted on 86 subjectively rated wood floors to determine average frequency and peak displacement values. From these tests, a design criterion was developed to predict acceptability of a wood floor system to vibrations.