This photo shows a window sill and brick wall during snow. The sill projects about 1/2" from brick face. A no drip edge is installed. Snow quickly melts and runs onto the facade, wetting its joints and penetrating microcracks. The glazed face of brick is a vapor barrier, which prevents moisture evaporation, so water saturates the brick and stays trapped. Later, during demolition, core holes of bricks were found full of ponding water. Freeze-thaw cycles cause brick spalling and cracking, leading to unsafe conditions.

Properly designed, well projected sills cornices and copings and drip edges at balconies and lintels protect exterior wall from quick deterioration. Unfortunately, many architects claim projected sills and drip edges look ugly. They choose to design a flush, crispy wall with deep horizontal setbacks collecting dirt. This is the effect of their work- See the next photo.