Overhangs

An overhang is a projecting portion of a structure or natural formation that extends beyond its supporting base. The term is used for both man-made projections, such as roofs, eaves, and cantilevers, and for natural rock ledges formed by differential erosion.

Architectural overhangs shelter walls from weather, shade interiors, and contribute to the building’s appearance. They range from simple eaves to long cantilevers and require appropriate structural support and weatherproofing. Design must account for loads, wind, temperature effects, moisture resistance, and maintenance to prevent sagging or collapse.

Geologic overhangs form when erosion or weathering undercuts a rock shelf, leaving a free-standing edge. They can be stable for long periods but may become hazardous if continued erosion or freezing and thawing weakens the base, potentially leading to rockfalls. They are of interest in geomorphology and are common on cliffs and in cave entrances.

In dentistry, an overhang is excess restorative material that extends beyond the margin of a tooth preparation after filling or crown work. Overhangs can trap plaque, irritate gums, and raise the risk of caries. Diagnosis uses clinical examination and radiographs; treatment involves removal of the excess material and recontouring or redoing the restoration.