One of this magazine's readers recently requested information on joint filler materials for heavy industrial floors, stipulating that ordinary materials had already proved unsatisfactory for the application in question due to excessive chipping in the joint area. One solution to this not uncommon problem is to use lead to fill the joints in areas where heavy traffic is anticipated. Joints filled in this fashion have less tendency to chip under heavy wheeled traffic because the lead gives considerably more support to the edges of the concrete than can be expected of an ordinary mastic material. In one project, the tooled joints in the concrete were made to accommodate one-fourth of an inch thick by 1 inch deep extruded lead strips. The tooled joints were made slightly less than 1 inch deep to allow one-sixteenth to one-eighth of an inch of lead to project above the surface. This excess material was carefully hammered down to the approximate level of the floor after the lead strips had been placed in the joints. This technique is said to be more satisfactory than the old-fashioned method of filling the joints with molten lead, which necessarily involved danger of spalling because of the considerable amount of heat brought in contact with the concrete. The use of molten lead also makes it essential that the joint be free of moisture at the time it is filled, whereas there is no such requirement with the extruded lead strips.