Control joints in a concrete block wall should be sealed with caulking compound after the mortar has been raked out to a depth of ____________.

Control joints in a concrete block wall should be sealed with caulking compound after the mortar has been raked out to a depth of ____________.

• A. 3/4 inch
• B. 1/2 inch
• C. 1 inch
• D. 1/4 inch

Answer: (A)

Control joints are placed to allow movement in masonry walls and prevent cracking, so the joint must be prepared to receive a durable, elastic sealant. Raking out the mortar to a depth of three quarters of an inch gives enough space for the caulking bead (and backer rod, if used) to sit properly and move with the joint. This depth supports good adhesion and performance of the sealant under expansion and contraction. If the joint is too shallow, the sealant may not adhere well or fail with movement; if it’s deeper, you waste material and risk a weaker bond. Therefore, three quarters of an inch is the appropriate depth.

Control joints are placed to allow movement in masonry walls and prevent cracking, so the joint must be prepared to receive a durable, elastic sealant. Raking out the mortar to a depth of three quarters of an inch gives enough space for the caulking bead (and backer rod, if used) to sit properly and move with the joint. This depth supports good adhesion and performance of the sealant under expansion and contraction. If the joint is too shallow, the sealant may not adhere well or fail with movement; if it’s deeper, you waste material and risk a weaker bond. Therefore, three quarters of an inch is the appropriate depth.