A shadow gap is an engineered break in between two surfaces. These spaces are a design choice for flush wall doors, as the door’s frame and surface are usually not in close proximity. This helps create a more seamless look and feel. Shadow gaps are also beneficial for other purposes. For example, they prevent the telltale shadow that would be cast by a proud surface on a flush wall door. They are also useful for creating a sleek and simple appearance for an entire wall.