A surface divider joint designed to allow free movement between new and existing construction or between different materials.

A substance, such as calcium chloride, added to a concrete mix to speed up its setting and strength development.

A raised finish floor surface consisting entirely of small, individually removable panels beneath which wiring, ductwork, and other services may be installed.

A ceiling of fibrous tiles that are highly absorbent of sound energy.

Science dealing with the production, control, transmission, reception and effects of sound, and the process of hearing.

The pressure exerted by retained earth against a retaining wall.

A prepared substance added to concrete to alter or achieve certain characteristics.

Sand, gravel, crushed stone or other material that is a main constituent of Portland Cement, concrete and aggregated gypsum plaster. Also, polystyrene, perlite and vermiculite particles used in texture finishes.

American Insurance Assn., successor to the National Board of Fire Underwriters and a nonprofit organization of insurance companies. Also, American Institute of Architects.

The incorporation of tiny air bubbles into concrete or mortar to improve its workability and resistance to freezing.

A membrane enclosing a pressurized occupied space, which must be held down to its foundation.

Sound traveling through the medium of air.

The maximum unit stress permissible in a structural member. Also referred to as working stress.

Metal securing device embedded or driven into masonry, concrete, steel or wood.

Heavy, threaded bolt embedded in the foundation to secure sill to foundation wall or bottom plate of exterior wall to concrete floor slab.