The interior concrete masonry wall at a warehouse that I am working on has developed vertical cracks at approximately 12-feet on-center. These cracks generally coincide with the column lines and are halfway between the columns. The actual spacing varies somewhat, but is very close to this pattern.
Do these cracks create any problems? How can they be avoided?
The cracking is most likely resulting from drying shrinkage of the concrete masonry. Because of regular spacing, it seems less likely to be associated with any loading from the structure.
In most warehouses the concrete masonry walls span from the floor system to the roof structure, rather than between columns. Therefore, it is unlikely that the vertical cracks reduce the strength of the wall system. The cracks are avoided by providing reinforcement in the bed joints of the concrete masonry and by using control joints at roughly 15 to 20 feet on-center.
More guidance for the installation of control joints is found in the National Concrete Masonry Association’s Technical Note 10-2B. Control joints should be provided at regular spacing and at all corners, offsets, and changes in support conditions.