Why are raked and struck mortar joints considered bad?

Raked and struck mortar joints are often seen as problematic primarily because they create a ledge where water can collect. This design feature inadvertently encourages water to pool on the joint rather than allowing it to run off or drain away from the wall surface. When water is trapped in this manner, it can lead to various issues, including increased moisture penetration into the structure, which can promote mold growth, deterioration of materials, and ultimately compromise the integrity of the wall.

The focus on water management is critical in construction and masonry work, as excess moisture can lead to significant structural problems over time. Proper joint design, which ensures effective water management, is imperative to maintain the longevity and durability of the building envelope.