Which of the following is NOT classified as fenestration?

Fenestration refers to the design and arrangement of openings in a building, primarily including windows, doors, and skylights. These openings play a crucial role in allowing natural light to enter, providing ventilation, and contributing to the aesthetic appeal of a structure.

Vertical windows, opaque doors, and skylights are all classified under fenestration because they facilitate light entry or access to the outside. Vertical windows and skylights are specifically designed to let in light and air, while opaque doors can provide an entry point, even if they are not transparent.

Exterior walls, however, are not considered fenestration. They serve as the primary structural component of the building, supporting the roof and enclosing the space within. While exterior walls can contain fenestration elements like windows and doors, the walls themselves do not fit the definition of fenestration, which focuses on the openings designed for light and access rather than the solid structural components. This distinction is fundamental in understanding building design and compliance with residential codes.