Many older masonry buildings suffer distress. One of the most common and easily addressed issues is the stress cracking of masonry elements due to the absence of or improper spacing of expansion joints.
Cracking caused by masonry movement is quite common and often results in diagonal cracks that radiate from an opening or irregularity in the wall.
Shrinkage cracks are not structural and they will not weaken the building but they can be unsightly and can lead to water penetration in exterior walls. To prevent shrinkage cracks, stresses within the wall must be reduced through the use of control joints.
Control joints are planned vertical wall separations. They basically divide a wall into separate panels, similar to what happens naturally after shrinkage cracks occur. The control joint provides a vertical bond break within the wall, which allows longitudinal movement. Using backer rod and sealant in the mortar joint spaces help the joints be weather-tight.