What is one of the main purposes of installing counter-flashing in masonry walls?

The main purpose of installing counter-flashing in masonry walls is to prevent moisture intrusion. Counter-flashing is a crucial component in roofing and masonry applications, designed to shed water away from vulnerable areas, particularly where different materials meet, such as the junction of a roof and a wall. By effectively directing water away from these intersections, counter-flashing helps to prevent moisture from penetrating the masonry structure, which can lead to deterioration, mold growth, and other moisture-related issues.

In relation to the other purposes mentioned, beautification can be a secondary benefit of counter-flashing, but it is not its primary function. Proper drainage is important in construction, but counter-flashing specifically addresses the sealing of joints and overlaps to keep water out rather than solely focusing on drainage pathways. Improving insulation is not a function of counter-flashing; it primarily serves a protective role regarding moisture management in masonry structures. Thus, the correct choice highlights the critical role counter-flashing plays in maintaining the integrity and longevity of masonry walls through moisture prevention.