| Term | Definition |
| J Channel | Metal edging used on drywall to give the edge a better finished appearance when a wall is not "wrapped" Generally, basement stairway walls have drywall only on the stair side. J Channel is used on the vertical edge of the last drywall sheet. |
| J-Box | An electrical junction box. |
| J-Mold | A metal molding strip with a J-like section, used to edge plaster or gypsum wallboard. |
| Jack | A mechanical device for lifting heavy objects. |
| Jack Arch | 1. One having horizontal or nearly horizontal upper and lower surfaces; also called a Flat Arch or Straight Arch. 2. Any arch that is roughly built. |
| Jack Plane | A medium sized plane used in the first stages of planing. |
| Jack post | A type of structural support made of metal, which can be raised or lowered through a series of pins and a screw to meet the height required. Basically used as a replacement for an old supporting member in a building. See Monopost. |
| Jack Rafter | 1. A short rafter that joins a hip rafter to the top of the wall plate. 2. A short rafter that joins a valley rafter to a ridge board. |
| Jack rafter | A rafter that spans the distance from the wall plate to a hip, or from a valley to a ridge. |
| Jack-of-all-Trades | A person who can do many different kinds of work. |
| Jacket, Aluminum | See Aluminum Jacket. |
| Jackhammer | A pneumatic concrete breaker. |
| Jacking Equipment | In prestressed concrete, the device used to stress the tendons. |
| Jacking Force | The temporary force exerted by a device that introduces tension into prestressing tendons in prestressed concrete. |
| Jacking Pipe | Forcing pipe through the ground in a tunnel created by the pipe itself; the pipe is generally jacked horizontally in short lengths. |
| Jacking Stress | In prestress concrete, the maximum stress occurring in a tendon during stressing. |
| Jacquard | Mechanism for a Wilton carpet loom which produces the desired color design using a chain of perforated cardboard cards punched according to the design elements, which when brought into position activates this mechanism by causing it to select the desired |
| Jacquard | The name of the loom which originally had a series of punched cards to control the weaving of the threads; computerized versions are used today. The resulting patterns are usually multi- colored and elaborate. |
| Jagged Edges | Irregularities left on the edges of ceramic tile due to the use mainly of hand cutting tools. |
| Jalousie | A blind or shutter made of a row of angled slats to keep out rain and control the influx of light. |
| Jalousie Window | A window with stationary or adjustable blinds angled to permit air and provide shade, while preventing rain from entering. |
| Jamb | The side and head lining of a doorway, window, or other opening. |
| Jamb | The side and head lining of a doorway, window, or other opening. Includes studs as well as the frame and trim. |
| Jamb | The vertical side of a door or window frame. |
| Jamb Anchor | Steel anchor used to fasten a steel door frame to the wall or partition construction. |
| Jamb Block | A concrete masonry unit with a preformed slot to receive a window or door frame. |
| Jamb, Door | See Door Jamb. |
| Japan Color | Colored paste made by grinding high-quality colors in hard drying varnish. |
| Japan Drier | Varnish gum with a large proportion of metallic salts, such as lead, cobalt, or manganese, added to hasten drying; used in paints, varnishes, and enamels. |
| Japanese Lacquer | Varnish made from sap of a tree which grows in Japan; becomes very hard and black as it dries. |
| jardiniËre curtains | Usually sheer, with the bottom of the curtain rising in the center to give a curved finish and reveal some of the window. |
| Jaspe | Carpet surface characterized by irregular stripes produced by varying textures or shades of the same color. |
| Jetting | A method of placing piles or sheeting by forcing water around and under a pile or sheeting to displace and lubricate the surrounding soil, allowing the pile or sheeting to sink to the desired position. |
| Jib | The arm of a crane. |
| Jib Crane | A crane which has a projecting arm off its derrick boom. |
| Jig | A tool or template used to maintain mechanically the correct positional relationship between a piece of work and the tool or between parts of work during assembly. |
| Jiggering | Forming ceramic ware from a plastic body by differential rotation of a profile tool and mold, the mold having the contour of one surface of the ware and the profile tool that of the other surface. |
| Jigsaw | 1A machine saw with a narrow reciprocating blade used for cutting curved and intricate patterns. 2. A scroll saw. |
| Jitterbug | A grate tamper for pushing coarse aggregate slightly below the surface of a slab to facilitate finishing. |
| Joanna | Roller shade fabricator. A division of Newell. (4110 Premier Drive, Highpoint, NC 27265) |
| Job | A piece of work. |
| Job Built Form | A temporary structure or mold constructed on a jobsite, for the support of concrete while it is setting and gaining sufficient strength to be self-supporting. |
| Job Lot | A miscellaneous collection of goods for sale as a lot. |
| Job Requirements | A list of specific, necessary, and essential tasks to bring to completion a building or structure; also called General Requirements. |
| Job Scheduling | An itemization in chronological order, often in chart form, of project tasks in order to start and complete a building or structure. |
| Job Trailer | A towed vehicle placed on a jobsite, acting as an office space. |
| Jobsite | The place where construction takes place. |
| Joinery | The art or trade of joinery; woodwork; finish carpentry. |
| Joining | The juncture of two separate plaster applications usually within a single surface plane; also called a Jointing. |
| Joint | 1. The location where two or more members are to be joined. 2. The point of connection between structural members. 3. The seam produced by the placement of two pieces of gypsum board together but not necessarily in the same plane. 4. The junction of two p |
| Joint cement | A powder that is usually mixed with water and used for joint treatment in gypsum-wallboard finish. Often called "spackle." |
| Joint Cement | See Joint Compound. |
| Joint cement or Joint compound | A powder that is usually mixed with water and used for joint treatment in gypsum-wallboard finish. Often called "spackle" or drywall mud. |
| Joint Check | A check made payable to more than one payee. |
| Joint Clip | 1. A metal fastener used vertically, sharp edge down, over the edges of two pieces of wood, and then hammered down into them. 2. In plywood sheathing, the clip fastens two abutting pieces of plywood. |
| Joint Compound | A cementitious material used in covering joints, corners and fasteners in the finishing of gypsum board to produce a smooth monolithic surface; also called Spackle or Joint Cement. |
| Joint Control | An independent escrow used to safeguard and disburse construction funds. |
| Joint Efficiency | The strength of a wood joint expressed as a percentage of the strength of clear straight-grained material. |
| Joint Factor | Joint efficiency. |
| Joint Filler | Compressible material used to fill a joint to prevent the infiltration of debris and to provide support for sealants. |
| Joint Photographing | In gypsumboard, the shadowing of the finished joint areas through the surface decoration. |
| Joint Reinforcement | Steel wire, bar, or prefabricated reinforcement which is placed in mortar bed joints. |
| Joint Reinforcing Mesh | A woven fiber screen-like material used in lieu of paper joint tape. |
| Joint Reinforcing Metal | Strips of expanded metal, woven or welded wire mesh used to reinforce corners and other areas of plaster and lath. |
| Joint Reinforcing Tape | A type of paper, metal, fabric, glass mesh, or other material, commonly used with a cementitious compound, to reinforce the joints between adjacent gypsum boards. |
| Joint Sealant | Compressible material used to exclude water and solid foreign materials from openings; a substance that prevents water and moisture from entering joints; also called Joint Sealer. |
| Joint Sealer | Joint Sealant. |
| Joint Tape | Paper tape that is applied with gypsum-based joint compound to treat the joints in gypsum wallboard. |
| Joint Tape System | The compound and tape system used to conceal and finish joints in gypsum board. |
| Joint tenancy | A form of ownership in which the tenants own a property equally. If one dies, the other automatically inherits the entire property. |
| Joint Tenants | Two or more persons owning property together with the right of survivorship. |
| Joint trench | When the electric company and telephone company dig one trench and "drop" both of their service lines in. |
| Joint Venture | A temporary partnership composed of individuals, partnerships, or corporations organized to accomplish a specific job or course of work. |
| Joint, Butt | See Butt Joint |
| Joint, Contraction | See Contraction Joint. |
| Joint, Control | See Control Joint. |
| Joint, Expansion | See Expansion Joint. |
| Jointer | 1. A metal hand tool used to cut a joint partly through fresh concrete. 2. In masonry, a tool used by bricklayers to form the various types of mortar joints between the courses of masonry, as the V, the concave, and weather joints. 3. An electrically powe |
| Jointing | 1. Smoothing and straightening the edge of a wood board. 2. Jointing is done automatically by a jointer. 2. Grinding or filing the teeth or knives of power tools to the correct height; circular saws are jointed so that there are no high or low teeth; kniv |
| Jointing, A | See Joining. |
| Joist | A, usually horizontal, structural member used as a floor, ceiling or roof framing member. |
| Joist Anchor | A metal rod incorporated into a masonry wall that extends out to be fastened to a joist or rafter. |
| Joist Bridging | 1. The bracing of joists by the fixing of lateral members between them. 2. Pieces fitted in pairs from the bottom of one floor joist to the top of adjacent joists, and crossed to distribute the floor load. 3. Wood pieces of width equal to the joists and f |
| Joist Girder | A light steel truss used to support open-web steel joists. |
| Joist hanger | A metal "U" shaped item used to support the end of a floor joist and attached with hardened nails to another bearing joist or beam. |
| Joist Hanger | A metal stirrup that supports the ends of joists so that they are flush with the girder. |
| Joist Painting | The act or process of applying paint to seal, protect, or add color to a joist, usually refers to metal joists. |
| Joist, Metal | See Metal Joist |
| Joist, Sister | See Sister Joist. |
| Joist, Wood | See Wood Joist. |
| Joule | In the international system of units, the amount of energy needed to raise the temperature of 1 kilogram of water 1 degree Celsius. |
| Joule-Thomson Effect | The change in the temperature of a gas on its expansion through a porous plug from a higher pressure to a lower pressure. |
| Journal | 1. A record of current transactions. 2. A log. 3. The part of a rotating shaft, axle, roll, or spindle that turns in a bearing. |
| Journal, Crankshaft | Part of shaft which contacts the bearing on the large end of the piston rod. |
| Journeyman | 1. A fully trained and qualified person in a craft or trade such as a carpenter, plumber, or electrician. 2. A plasterer or lather who through training and experience has become thoroughly skilled in his trade; distinguished from an apprentice or a labore |
| Judgment | A final decision of a court. |
| Jumbo Brick | A brick that is larger than standard size and measures 8"x4"x4". |
| Jumpers | Water pipe installed in a water meter pit (before the water meter is installed), or electric wire that is installed in the electric house panel meter socket before the meter is installed. This is sometimes illegal. |
| Jumpover | In piping, a double offset used to return the pipe to its original line; also called a Return Off-Set. |
| Junction Box | A metal or hard plastic electrical rough-in box, usually square or octagonal, housing only wire or cable connections. |
| Jute | Strong, durable yarn spun from fibers of the jute plant, native to India and Far East, used in the backings of many carpets. |
| Jute Padding | A padding made of a durable yarn that comes from plant fiber used as an underlayment for carpet. |
| Juxtaposition | The placing of things side by side. |
| Juxtaposition of Colors | Placing colors side-by-side, or close together; complementary colors such as blue and orange in juxtaposition accentuate each other. |