Back Draft – The reverse flow of chimney gases (blowing back down the chimney) because of poor chimney design or weather conditions.

Back-up Sump Pump – A battery operated sump pump that operates if the main sump pump fails because of a malfunction or a power outage.

Band Board – board attached to the ends of the floor joists around the outside of the structure.

Base Flashing – A portion of the flashing attached to or resting on the deck, to direct the flow of water onto the roof covering.

Beam – Any structural member can be wood or steel.

Back Fill – Soil that is used to fill in between the foundation wall and the side of the trench that was dug to lay the foundation.

Balloon Framing – Method of wood frame construction used in older homes in which the studs extend as one-piece from the foundation to the roof.

Baseboard – A decorative molded board placed against the wall at floor level to cover the joint between the floor and the wall.

Baseboard Heater – A radiator mounted along the baseboard with openings at the top and bottom through which the air circulates. May be electric, or heated by hot water.

Base Course – The first row of bricks or blocks laid.

Basement – Lower store of a building below or party below ground.

Batten – Narrow strip of wood used to cover joints between boards or paneling.

Bay Window – A window that extends outside the main line or frame of the building.

Beam – Wood, steel or concrete member used to support a great weight.

Bearing Wall – Wall that supports the area above it. This type of wall cannot be removed without restructuring the areas above it.

Bevel Siding – Boards where one edge is tapered, slots under the board above it. Used for exterior siding.

Blind Nailing – Method of nailing so than nail heads are not visible on the face of the work.

Blisters – Bubbles that may appear on the surface of asphalt roofing after installation.

Board – Any finished lumber less than two inches thick and wider than four inches.

Brace – A diagonal framing member used in framing to stiffen the structure.

Branch Circuit – Is a circuit that comes off the main circuit.

Brands – Marks on a roof from airborne burning embers released from a fire.

Brick Molding – Wood trim piece used to cover the gap between window frames and the masonry.

Brick Veneer – Brick facing used as a covering, not load bearing. Attaches decoratively to the load bearing structure.

Bundle – A package of shingles. There are three, four or five bundles per square.

Building Paper – A felt or similar material usually used over the roof decking and under the shingles.

Built-up Roof – Roof covering composed of 3 or more layers of roofing felt and asphalt. Used on flat or low-pitched roofs.

Butt Edge – Lower edge of the tabs, on a shingle.

Butt-joint – Joint fastening two members together without any overlapping.

BX Wiring – Also called armored cable, the wiring is enclosed in flexible metal conduit type sheathing.