JND Enterprises

Control joints are typically used in concrete masonry to reduce the occurrence of shrinkage-related cracking. A control joint is a continuous vertical joint tha can be filled with mortar, but with a bond breaker on one side so that tensile stress cannot develop across the joint.

If control joints are not provided, a concrete masonry wall may crack as it shrinks over time.

Control joints should be provided at regular intervals along the wall's length and near corners, returns and changes in the wall's height, support or stiffness.

 

Control joints will not relieve masonry expansion.

Expansion joints, on the other hand, are typically used to accommodate thermal and moisture expansion in clay brick masonry. An expansion joint is a continuous vertical or horizontal joint, left completely free of mortar and filled with elastomeric sealant to keep it watertight.

Clay brick masonry expands over time. Expansion joints accommodate this expansion as the sealant compresses.

 

Building expansion joints are different from masonry expansion joints.

Building expansion joints are generally joints in the building structure that separate the building into different sections. Often wide, these joints are intended to accommodate movements that exceed those associated with the masonry itself.