| A | B |
|---|
| abrasive paper | Paper or cloth with an abrasive material glued to one side, used for smoothing wood or metal surfaces. |
| accelerating admixture | Concrete admixture that reduces concrete setting time and improves strength of concrete at an early stage. |
| acoustical tile | Ceiling tile with small holes and fissures that act as sound traps to reduce the reflection of sound. |
| active door | Door of a double-door unit used for normal traffic flow. |
| actual length of rafter | Length of a main rafter or valley jack rafter after it has been shortened because of ridge board and/or rafter thickness. |
| actual lumber size | Thickness and width of a piece of lumber after shrinkage resulting from drying and after surfacing. |
| adhesive | Substance used to bond two surfaces together, available in solid, liquid, and semi-liquid forms. |
| admixture | Substance other than water, Portland cement, or aggregate that is added to concrete to modify its properties. |
| aerial lift | Extendable or articulated equipment designed to position personnel and/or materials in elevated positions. |
| aggregate | Hard, granular material, such as sand and gravel, that is mixed with cement to provide structure and strength in concrete. |
| air compressor | Equipment used to compress air for pneumatic tools and equipment. |
| air-dried lumber | Lumber that has been dried to an acceptable moisture content by being stacked for period of time in the open air. |
| air duct | Pipe, usually rectangular and made of sheet metal, used to conduct hot or cold air in heating or cooling systems. |
| air-entraining admixture | Concrete admixture that produces microscopic air bubbles in concrete to improve its workability and its resistance to freezing and thawing. |
| air pocket | Void in hardened concrete caused by poor consolidation when the concrete was placed. |
| allowable span | Distance allowed between supporting points for various sizes of beams, joists, and roof rafters. |
| alteration work | Change or addition to an existing building, also called remodeling. |
| anchor bolt | Bolt used to secure sill plates, columns, and beams to concrete or other masonry. |
| anchor clip | Strap-like device embedded into the top of a foundation wall and used to fasten sill plates |
| anchor tiedown system | Connection device used in areas where the most extreme uplift due to seismic conditions or high winds is anticipated. |
| angle iron | Structural steel bent to form a 90 degree angle and used for support or fastening purposes. |
| annual ring | Layer of wood seen in cross section of a tree trunk indicating a year's growth. |
| annular nail | A nail with circular ridges on the shank to provide greater holding power. |
| apprenticeship | Training for a trade or skilled craft that requires a wide variety of skills and knowledge. Provided with instruction and on-the-job experience in practical and theoretical aspects of the trade. |
| apron | Trim piece placed below the stool of a finished window frame. |
| arbor | Shaft on which a cutting tool is mounted, such as the blade of a circular saw. |
| arc | Part of the circumference of a circle. |
| arch | Curved structure designed to support the weight above an opening. |
| architect | Person qualified and licensed to design and oversee construction of a building. |
| archway | Passage area under an arch. |
| areaway | Small sunken area allowing light or air into a basement window that is partially below the grade level around the building. Also called a "window well." |
| asphalt | Petroleum product obtained from crude oil. It is waterproof and is the basis for many products used for roof, wall, and floor covering. |
| asphalt shingle | Shingle made of asphalt-saturated felt and surfaced with mineral granules. Usually used as a finish roofing material. |
| astragal | Piece of molding attached to the edge of the inactive door of a pair of double doors. Serves as a stop for the active door. |
| attic | Space between a roof and a ceiling. |
| awning window | Window that is hinged at the top and swings out at the bottom. |
