Balusters    Usually small vertical members in a railing used between the rail and the stair treads or a bottom rail.
Balustrade    A railing made up of balusters, a top rail, and sometimes a bottom rail on the edge of stairs, balconies, and porches.
Bargeboard    Decorative board on the projecting edge or eaveline of a gable roof
Base molding    The molding at the top of an interior baseboard.
Base or baseboard    A line of boarding around the bottom of the interior walls of a room next to the floor.
Base sheet    Bottom layer of built-up roofing.
Batten    Narrow strips of wood used to cover joints or decorative vertical members over plywood or wide boards.
Bay    Vertical division of the exterior of a building
Beam    A horizontal, structural framing member designed to carry a load from a set of joists or a roof and spanning an open space. Usually 6" x 6" or 4" x 10" or larger.
Beam hanger    Used for beam-to-beam joints, to connect thick, wooden beams to supporting wooden beams.

Bearing wall    A wall that supports any vertical load in addition to its own weight.
Bitumen    Term commonly applied to various mixtures of naturally occurring solid or liquid hydrocarbons, excluding coal. These substances are described as bituminous. Asphalt is a bitumen.
Blocking    A piece of wood attached between joists, studs or rafters. They may be used as a fire stop, for shear load transfer. Blocking is also used as a nailing surface for finish materials.
Board and batten    Exterior cladding of alternating vertical stripes of wide and narrow wood place over the building paper and nailed to the exterior wall framing.
Bracing    A framing element of wood or metal applied diagonally to walls or floor to stiffen the structure, increasing its resistance to lateral forces.
Bracket    Support under a wide overhang
Brick veneer    A facing of thin brick laid against and fastened to the sheathing of a framed wall.
Bridging    Small wood or metal members that are inserted in a diagonal position between the floor joists at mid span to act both as tension and compression members for the purpose of bracing the joists and spreading the actions of loads.
Building paper    An asphalt saturated paper that is applied to the exterior of wall framing. It functions as a moisture barrier.
Building permit    authorization to build or modify a structure. Usually issued by local municipality.
Built-up roof    A type of commercial, or "flat" roof finish, produced by applying alternate layers of roofing felt and hot asphalt or pitch. The top layer is given a hot flood coat of the bitumen; granules of rock, gravel, slag, or ceramic particles may be embedded while the flood coat is still hot. The roofing system may incorporate rigid insulation.
Bundle    A package of shingles. Depending on the type of shingles, there are 3, 4 or 5 bundles per square (110 sq. ft.).
Butt edge    The lower edge of the shingle tabs.