Dictionary of Home Building Terms

A/C - An abbreviation for air conditioner or air conditioning.
A/C Condenser - The outside fan unit of the Air Conditioning system. It removes the heat from the freon gas and "turns" the gas back into a liquid and pumps the liquid back to the coil in the furnace.
A/C Disconnect - The main electrical ON-OFF switch near the A/C Condenser.
Aerator - The round screened screw-on tip of a sink spout. It mixes water and air for a smooth flow.
Aggregate - A mixture of sand and stone and a major component of concrete.
Air space - The area between insulation facing and interior of exterior wall coverings. Normally a 1" air gap.
Allowance(s) - A sum of money set aside in the construction contract for items which have not been selected and specified in the construction contract. For example, selection of tile as a flooring may require an allowance for an underlayment material, or an electrical allowance which sets aside an amount of money to be spent on electrical fixtures.
Amortization - A payment plan by which a loan is reduced through monthly payments of principal and interest.
Anchor bolts - Bolts to secure a wooden sill plate to concrete , or masonry floor or wall.
Annual Percentage Rate (APR) - Annual cost of credit over the life of a loan, including interest, service charges, points, loan fees, mortgage insurance, and other items.
Appraisal - An expert valuation of property.
Apron - A trim board that is installed beneath a window sill
Architect - One who has completed a course of study in building and design, and is licensed by the state as an architect. One who draws up plans.
Area wells - Corrugated metal or concrete barrier walls installed around a basement window to hold back the earth
Assessment - A tax levied on a property, or a value placed on the worth of a property.
Assumption - Allows a buyer to assume responsibility for an existing loan instead of getting a new loan.
Astragal - A molding, attached to one of a pair of swinging double doors, against which the other door strikes.
Attic access - An opening that is placed in the drywalled ceiling of a home providing access to the attic.
Attic Ventilators - In houses, screened openings provided to ventilate an attic space.

Back Charge - Billings for work performed or costs incurred by one party that, in accordance with the agreement, should have been performed or incurred by the party to whom billed. Owners bill back charges to general contractors, and general contractors bill back charges to subcontractors. Examples of back charges include charges for cleanup work or to repair something damaged by another subcontractor, such as a tub chip or broken window.
Backfill - The replacement of excavated earth into a trench around or against a basement /crawl space foundationwall.
Backing - Frame lumber installed between the wall studs to give additional support for drywall or an interior trim related item, such as handrail brackets, cabinets, and towel bars. In this way, items are screwed and mounted into solid wood rather than weak drywall that may allow the item to break loose from the wall. Carpet backing holds the pile fabric in place.
Backout - Work the framing contractor does after the mechanical subcontractors (Heating-Plumbing-Electrical) finish their phase of work at the Rough (before insulation) stage to get the home ready for a municipal frame inspection. Generally, the framing contractor repairs anything disturbed by others and completes all framing necessary to pass a Rough Frame Inspection.
Ballast - A transformer that steps up the voltage in a florescent lamp.
Balloon - A loan that has a series of monthly payments with the remaining balance due in a large lump sum payment at the end.
Balloon framed wall - Framed walls (generally over 10' tall) that run the entire vertical length from the floor sill plate to the roof. This is done to eliminate the need for a gable end truss.
Balusters - Vertical members in a railing used between a top rail and bottom rail or the stair treads. Sometimes referred to as 'pickets' or 'spindles'.
Balustrade - The rail, posts and vertical balusters along the edge of a stairway or elevated walkway.
Barge - Horizontal beam rafter that supports shorter rafters.
Barge board - A decorative board covering the projecting rafter (fly rafter) of the gable end. At the cornice, this member is a fascia board.
Base or baseboard - A trim board placed against the wall around the room next to the floor.
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.
Bat - A half-brick.
Batt - A section of fiber-glass or rock-wool insulation measuring 15 or 23 inches wide by four to eight feet long and various thickness'. Sometimes "faced" (meaning to have a paper covering on one side) or "unfaced" (without paper).
Batten - Narrow strips of wood used to cover joints or as decorative vertical members over plywood or wide boards.
Bay window - Any window space projecting outward from the walls of a building, either square or polygonal in plan.
Beam - A structural member transversely supporting a load. A structural member carrying building loads (weight) from one support to another. Sometimes called a "girder".
Bearing partition - A partition that supports any vertical load in addition to its own weight.
Bearing point - A point where a bearing or structural weight is concentrated and transferred to the foundation
Bearing wall - A wall that supports any vertical load in addition to its own weight.
Bearing header - (a) A beam placed perpendicular to joists and to which joists are nailed in framing for a chimney, stairway, or other opening. (b) A wood lintel. (c) The horizontal structural member over an opening (for example over a door or window).
Bedrock - A subsurface layer of earth that is suitable to support a structure.
Bid - A formal offer by a contractor, in accordance with specifications for a project, to do all or a phase of the work at a certain price in accordance with the terms and conditions stated in the offer.
Bid bond - A bond issued by a surety on behalf of a contractor that provides assurance to the recipient of the contractor's bid that, if the bid is accepted, the contractor will execute a contract and provide a performance bond. Under the bond, the surety is obligated to pay the recipient of the bid the difference between the contractor's bid and the bid of the next lowest responsible bidder if the bid is accepted and the contractor fails to execute a contract or to provide a performance bond. Bid security Funds or a bid bond submitted with a bid as a guarantee to the recipient of the bid that the contractor, if awarded the contract, will execute the contract in accordance with the bidding requirements of the contract documents.
Bid shopping - A practice by which contractors, both before and after their bids are submitted, attempt to obtain prices from potential subcontractors and material suppliers that are lower than the contractors' original estimates on which their bids are based, or after a contract is awarded, seek to induce subcontractors to reduce the subcontract price included in the bid.
Bidding requirements - The procedures and conditions for the submission of bids. The requirements are included ion documents, such as the notice to bidders, advertisements for bids, instructions to bidders, invitations to bid, and sample bid forms.
Bifold door - Doors that are hinged in the middle for opening in a smaller area than standard swing doors. Often used for closet doors.
Binder - A receipt for a deposit to secure the right to purchase a home at an agreed terms by a buyer and seller.
Bipass doors - Doors that slide by each other and commonly used as closet doors.
Blankets - Fiber-glass or rock-wool insulation that comes in long rolls 15 or 23 inches wide.
Blocked (door blocking) - Wood shims used between the door frame and the vertical structural wall framing members.
Blocked (rafters) - Short "2 by 4's" used to keep rafters from twisting, and installed at the ends and at mid-span.
Blocking - Small wood pieces to brace framing members or to provide a nailing base for gypsum board or paneling.
Block out - To install a box or barrier within a foundation wall to prevent the concrete from entering an area. For example, foundation walls are sometimes "blocked" in order for mechanical pipes to pass through the wall, to install a crawl space door, and to depress the concrete at a garage door location.
Blow insulation - Fiber insulation in loose form and used to insulate attics and existing walls where framing members are not exposed.
Blue print(s) - A type of copying method often used for architectural drawings. Usually used to describe the drawing of a structure which is prepared by an architect or designer for the purpose of design and planning, estimating, securing permits and actual construction.
Blue stake - Another phrase for Utility Notification. This is when a utility company (telephone, gas, electric, cable TV, sewer and water, etc) comes to the job site and locates and spray paints the ground and/or installs little flags to show where their service is located underground.
Board foot - A unit of measure for lumber equal to 1 inch thick by 12 inches wide by 12 inches long. Examples: 1" x 12" x 16' = 16 board feet, 2" x 12" x 16' = 32 board feet
Bond or bonding - An amount of money (usually $5,000-$10,000) which must be on deposit with a governmental agency in order to secure a contractor's license. The bond may be used to pay for the unpaid bills or disputed work of the contractor. Not to be confused with a 'performance bond'. Such bonds are rarely used in residential construction, they are an insurance policy which guarantees proper completion of a project.
Boom - A truck used to hoist heavy material up and into place. To put trusses on a home or to set a heavy beam into place.
Bottom chord - The lower or bottom horizontal member of a truss.
Bottom plate - The "2 by 4's or 6's" that lay on the subfloor upon which the vertical studs are installed. Also called the 'sole plate'.
Brace - An inclined piece of framing lumber applied to wall or floor to strengthen the structure. Often used on walls as temporary bracing until framing has been completed.
Breaker panel - The electrical box that distributes electric power entering the home to each branch circuit (each plug and switch) and composed of circuit breakers.
Brick ledge - Part of the foundation wall where brick (veneer) will rest.
Brick lintel - The metal angle iron that brick rests on, especially above a window, door, or other opening.
Brick mold -Trim used around an exterior door jamb that siding butts to.
Brick tie - A small, corrugated metal strip @ 1" X 6"- 8" long nailed to wall sheeting or studs. They are inserted into the grout mortar joint of the veneer brick, and holds the veneer wall to the sheeted wall behind it.
Brick veneer - A vertical facing of brick laid against and fastened to sheathing of a framed wall or tile wall construction.
Bridging - Small wood or metal members that are inserted in a diagonal position between the floor joists or rafters at mid-span for the purpose of bracing the joists/rafters & spreading the load.
Buck - Often used in reference to rough frame opening members. Door bucks used in reference to metal door frame. See Window Bucks
Builder's Risk Insurance - Insurance coverage on a construction project during construction, including extended coverage that may be added for the contract for the customer's protections.
Building codes - Community ordinances governing the manner in which a home may be constructed or modified.
Building insurance - Insurance covering the structure of the building.
Building paper - A general term for papers, felts, and similar sheet materials used in buildings without reference to their properties or uses. Generally comes in long rolls.
Built-up roof - A roofing composed of three to five layers of asphalt felt laminated with coal tar, pitch, or asphalt. The top is finished with crushed slag or gravel. Generally used on flat or low-pitched roofs.
Bull nose (drywall) - Rounded drywall corners.
Bundle - A package of shingles. Normally, there are 3 bundles per square and 27 shingles per bundle.
Butt edge - The lower edge of the shingle tabs.
Butt hinge - The most common type. One leaf attaches to the door's edge, the other to its jamb.
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.
Buy down - A subsidy (usually paid by a builder or developer) to reduce monthly payments on a mortgage.
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.
By pass doors - Doors that slide by each other and commonly used as closet doors.