2-13. Using Paper and Felt. You can make another type of control joint by inserting building paper or
roofing felt in the end core of the block and extending it the full length of the control joint. Cut the
paper or felt to convenient lengths. Make sure it is wide enough to extend across the joint to prevent the
mortar from bonding on one side of the joint (Figure 2-12).
Figure 2-12. Control joints using paper or felt
2-14. Caulking. If the control joints are exposed to the weather or to view, you should caulk them.
When the mortar in the control joint is stiff, rake it out to a depth of 3/4 inch to provide a recess for the
caulking materials (Figure 2-13, page 2-16 ). Use a thin, flat caulking trowel to force the caulking
compound into the joint.