wall

A wall is a vertical planar element that encloses or divides spaces in architecture and related fields. In buildings, walls form the perimeter and internal partitions. Exterior walls enclose the structure, resist weather, and provide insulation; interior walls separate rooms and may be load-bearing or non-load-bearing. Structural walls, such as load-bearing masonry or reinforced concrete walls, carry loads, while partition walls primarily define space. Retaining walls hold back earth on sloped ground. A firewall is a wall or barrier designed to resist the spread of fire for a defined period.

Materials and methods vary. Walls can be masonry (brick or stone), concrete, timber framing with studs, or metal panels, and are often clad with plaster, drywall, siding, or stucco. They may be solid or hollow, with insulation and air barriers in between. Performance is measured by thermal resistance (R-value), sound transmission (STC), airtightness, and fire resistance ratings, all governed by building codes.

Notable examples include the Great Wall of China and the Western Wall; the Berlin Wall is remembered as a symbol of political division. In biology, a cell wall surrounds plant and fungal cells and provides structure and protection.

Maintenance concerns include cracks, dampness, and moisture intrusion; repairs can involve repointing masonry, patching plaster or drywall, sealing joints, and upgrading insulation. Walls thus serve structural, environmental, and social roles, shaping how interior space is used and experienced.