When drilling into a brick exterior, which part is preferable to avoid compromising the structure?

Drilling through the mortar is preferable when working with a brick exterior because mortar is designed to absorb movement and stress in the wall. It is generally more forgiving than brick itself, which can crack or chip if drilled directly. Mortar joints are typically easier to repair if damage occurs during drilling, making it a more suitable choice for maintaining the integrity of the wall. Additionally, drilling into mortar instead of the brick reduces the risk of compromising the structural stability of the brick, especially in load-bearing situations. By choosing mortar, you also avoid the potential for damaging the brick's face or structure, which could lead to more extensive repairs.