Butt edge
- The lower edge of the shingle tabs.
Buy down
A subsidy (usually paid by a builder or developer) to reduce monthly payments on a mortgage.
Butt joint
The junction where the ends of two timbers meet, and also where sheets of drywall meet on the 4 foot edge. To place materials end-to-end or end-to-edge without overlapping.
Busway
A rigid conduit used to protect a bus running through it.
By pass doors
Doors that slide by each other and commonly used as closet doors.
Butt hinge-
The most common type. One leaf attaches to the door's edge, the other to its jamb.
BX Cable
A cable sheathed with spirally wrapped metal strip identified as Type AC.
Bus
A rigid electric conductor enclosed in a protective busway.
By fold door
Doors that are hinged in the middle for opening in a smaller area than standard swing doors. Often used for closet doors.
Burning
Curing bricks by placing them in a kiln and subjecting them to a high temperature.
Bat
- A half-brick.
Basement window inserts
The window frame and glass unit that is installed in the window buck.
Base shoe
Molding used next to the floor on interior base board. Sometimes called a carpet strip.
Batt
A section of fiber-glass or rock-wool insulation measuring 15 or 23 inches wide by four to eight feet long and various thicknesses. Sometimes "faced" (meaning to have a paper covering on one side) or "unfaced" (without paper).
Batch
The amount of concrete mixed at one time.
Batten
Narrow strips of wood used to cover joints or as decorative vertical members over plywood or wide boards. Narrow strip of wood, plastic, metal or gypsum board used to conceal an open joint.
BCMC
Board for the Coordination of Model Codes; part of the Council of American Building Officials Association (CABO).
Bay window
Any window space projecting outward from the walls of a building, either square or polygonal in plan.
Bauxite
Ore containing high percentages of aluminum oxide.
Beam
A structural member transversely supporting a load. A structural member carrying building loads (weight) from one support to another. Sometimes called a "girder". A straight horizontal structural loadbearing member spanning a distance between supports.