Joint spacing varies with amount and grade of shrink-age and temperature reinforcement. 80 ft (25 m) for walls and insulated roofs, 30 to 40 ft (9 to 12 m) for uninsulated roofs. But do you know what concrete cold joints are? A cold joint in concrete is an area or surface with a structural discontinuity caused by the delayed concrete pouring between two layers of concrete. This discontinuity occurs because the older material has passed its initial setting time, preventing a true chemical bond with the fresh mix. An example is the joint that separates the floor slab from a column. Isolation joints are sometimes. Contraction joints are intended to create weakened planes in the concrete and control the location where cracks, resulting from dimensional changes, will occur. In this comprehensive guide, we'll delve into all aspects of cold joints in concrete.