| Bond | Pattern for laying bricks so that none of the perpends are in line in adjacent courses. |
| Block out | when material is installed into a wall for additional support for hang items such as handrails and towel rails. |
| Birdsmouth | A notch cut out of roof rafters to secure a firm bearing on top plates. |
| Benchmark | A fixed point of reference, the elevation of which is known and referred to during levelling operations.
|
| Bearer | In the context of commercial construction in Australia, a bearer refers to a horizontal structural member that supports the floor or roof joists and transfers the weight of the floor or roof to the foundation or supporting walls . |
| Beam and joist floor | beam and joist arrangements can form a supporting frame for a floor. Beams are thicker and longer and are laid vertically; joists are typically shorter and lay across the beams to give them horizontal support. |
| Beam | a structural member transversely carrying a load. Sometimes called a "girder," these are often used in open plan homes. |
| Bead | In the context of commercial construction in Australia, a bead refers to a type of sealant or filler used to fill gaps and joints in building elements, such as walls, windows, and doors. The purpose of a bead is to provide a weather-tight seal, prevent air leakage, and ensure the structural integrity of the building. |
| BCA | The Building Code of Australia (BCA) is a comprehensive set of regulations governing the design and construction of buildings in Australia, including commercial construction . It is a national set of technical requirements for the design, construction, and performance of buildings .
|
| Bay Window | A bay window in commercial construction in Australia is a straight-sided construction, containing one or more windows, that projects from the face of a building and thereby forms a bay in the associated room . |
| Batter | In the context of commercial construction in Australia, a batter refers to the sloping or angled surface of an excavation or earthwork, typically to prevent collapse or erosion |
| Batten | Timber member of small, rectangular cross-section. Sometimes used to screen the undercroft area. |
| Batt | In the context of commercial construction in Australia, a batt refers to a type of insulation material used to reduce heat transfer and energy loss in buildings. Specifically, it is a flexible, blanket-like material made of fiberglass, wool, or other materials, designed to fit between studs, joists, or other structural elements in walls, floors, and ceilings. |
| BASIX | The Building and Sustainability Index (BASIX) is a web-based planning tool designed to assess the potential performance of residential buildings against a range of sustainability indices in New South Wales (NSW), Australia . However, BASIX is not directly applicable to commercial construction. Instead, it is compulsory for all residential buildings and is part of the development application process . |
| Basement | In Australia, a basement is defined as a storey that is below ground level, as per the Building Code of Australia (BCA) . The BCA provides the minimum necessary requirements for the design and construction of buildings, including commercial buildings . |
