MJM Acoustical Consultants INC. has been selected by the Canada Mortgage & housing Corporation to conduct the first phase of a research project on the sound isolation provided by floor/ceiling assemblies in wood constructions. This report contains the results of our findings. The main objective of this first phase was to investigate the acoustical performance of different materials in the floor cavity along with ceiling finishes and installation methods. All the airborne and impact sound insulation tests have been conducted at the laboratories of the National Research Council of Canada under the direction of Dr. A.C.C Warnock.