Excerpt from the report Preface: This report covers work done under a long-range research project at the Wenatchee, Wash., field office of the Transportation and Facilities Branch, Marketing Research Division, Agricultural Marketing Service, to improve the operation and design of cold storage houses for apples and other tree fruits. It is in two parts, one dealing with the heat flow through the floors of storage houses and the merits of insulating the floors, and the other dealing with the same two factors for walls and ceilings.