| Term | Definition |
| H Beam | A steel beam which in cross section resembles the letter H; commonly used in earthwork as a retaining structure or piling. |
| H Clip | Small metal clips formed like an "H" that fits at the joints of two plywood (or wafer board) sheets to stiffen the joint. Normally used on the roof sheeting. |
| H V A C | An abbreviation for Heat, Ventilation, and Air Conditioning |
| Hack | 1. To cut with irregular or unskilled blows. 2. To cut back and roughen a plastered or other surface. |
| Hacking | Laying masonry units so that the bottom edge is set back from the plane surface of the wall. |
| Hacksaw | Small toothed handsaw for sawing metals. |
| Hair Trap | A device to trap and retain the hair content of waste water and sewage, as in a barber shop or beauty salon. |
| Hairline Cracking | 1.Tiny cracks in a surface. 2. Small cracks of random pattern in an exposed concrete surface. 3. Very narrow cracks in a paint or varnish film. |
| Hairpin Bars | Bars, usually small sizes, bent to a hair pin shape and used for such purposes as short hooked spacer bars in columns and walls and for special dowels. |
| Half and Half | A dry or dampened mixture of one part portland cement and one part extra-fine sand; used as a filler in the joints of mounted ceramic mosaic tiles to keep them evenly spaced during installation. |
| Half Bath | A room containing a toilet and a lavatory. |
| Half Block | A concrete masonry unit that is half the length of a standard unit. |
| Half Round Gutter | A narrow rounded channel from one piece of metal, similar to a pipe cut longitudinally or along its length, used as a gutter. |
| Half Round Molding | An ornamental strip having one flat side and one rounded side. |
| half-tester | A rectangular canopy above a bed, extending only part-way down the bed from the headboard. The curtain draped at either side created a shallow three-dimensional effect. |
| Half-Timber | A form of construction composed of timber framing with the spaces filled in with brick or plaster. |
| Halide Fixture | A lighting fixture with a Halide Light. |
| Halide Light | An electric-discharge lamp that makes its light from a metal vapor such as sodium or mercury. |
| Halide Refrigerants | Family of refrigerants containing halogen chemicals. |
| Halide Torch | Type of torch used to safely detect halogen refrigerant leaks in system. |
| Hall | 1. Lobby or entrance room. 2. A university building for a special purpose. 3. A hallway or corridor. |
| Hallway | A corridor or hall. |
| Halogens | Any of the group of poisonous non-metallic elements, fluorine, chlorine, bromine, iodine, and astatine, which form halides by simple union with a metal, as in sodium chloride. |
| Halon System | A system using halon gas for the fire protection of water sensitive equipment. |
| Hammer | A handtool consisting of a solid head set crosswise on a handle and used for pounding. |
| Hammer Fracture | A tear in the gypsum board face and core caused by improperly hitting or over driving the nail; also called Nail Fracture. |
| Hammer Loss | A test to determine the impact resistance of gypsum board. |
| Hammered Effect Finish | So called because of its resemblance to hammered metal; produced by incorporating an aluminum powder in vehicle which controls leafing and nonleafing effect to create unique designs. |
| Hand | The feel of a carpet in the hand; determined by such factors as pile height, quality and kind of fibers, type of construction, type of backing, and dimensional stability. |
| Hand Buggy | A hand pushed or pulled two or four wheeled cart, used to transport small amounts of concrete or material. |
| Hand Dryer | A mechanical/electrical device that blows hot air over wet hands to dry them. |
| Hand Excavation | The act or process of digging out earth using hand tools. |
| Hand Level | A hand-held viewing tube with a spirit level attached to fix a level line of sight. |
| Hand of a Lock or Door | Indicates the direction of swing or movement and/or locking security side of a door; designated as left hand, left hand reverse, right hand, or right hand reverse. |
| Hand Prints | Wallpapers printed by hand, usually with the silk- screen process. |
| Hand Seeding | The act or process of planting seed by hand. |
| Handed Locks | Locks that must be used on the same handed door, as opposed to reversible locks. |
| Handhole | 1. Access hole used for repair and cleaning. 2. An enclosure installed in the earth, deck, floor of a building, or similar location and used as a pull or junction box for underground electrical or communication conductors; the enclosure is provided with a |
| Handicapped Parking | A parking space designated as reserved for the vehicles of disabled persons. |
| Handicapped Partition | A dividing wall that forms a toilet cubicle area that is accessible to the disabled; commonly larger than a standard cubicle, large enough for wheelchair access. |
| Handicapped Plumbing | Plumbing devices and layouts specifically designed for use by disabled individuals. |
| Handicapped Symbol | The profile of a wheelchair and occupant placed on a sign to denote access for disabled persons. |
| Handling, Air | See Air Handling System. |
| Handling, Rubbish | See Rubbish Handling. |
| Handling, Trash | See Trash Handling. |
| Handling, Waste | See Waste Handling. |
| Handrail | Member which is normally grasped by hand for support at stairways and other places where needed for safety of pedestrians. |
| Handrail Bracket | A support for a handrail. |
| Handrail, Pipe | See Pipe Handrail. |
| Handsaw | A wood saw which is powered by hand, commonly called a Carpenter's Saw or Wood Saw. |
| Handsplit Shingle | A shingle made by splitting a block of wood, usually cedar or redwood, along its grain and thereby creating a shingle which may be used for roofing or siding; also called Shakes or Shake Shingles. |
| Hang | To install certain materials such as gypsum lath, gypsum wallboard, or wallpaper. |
| Hangar | A shelter for storing and repairing aircraft. |
| Hanger | 1. A tradesman who applies gypsum board products. 2. Vertical-tension member supporting a load. 3. Device attached to walls or other structure for support of pipe lines. |
| Hanger Rod | A rod for connecting pipe, gutters, or ceiling framework to a support. |
| Hanger Wire | Malleable wire for hanging ceilings and equipment from the structure above. |
| Hanger's Bench | See Bench, 4. |
| Hanger's Tee | See Tee Square. |
| Hanger, Door Rail | See Door Rail Hanger. |
| Hanger, Joist | See Joist Hanger. |
| Hansa Yellow | A family of organic yellow pigments. |
| Hard Edge | A special core formulation used along the paperbound edges to improve resistance to damage during the handling and application of gypsum board. |
| Hard Money | The actual cash paid to a seller in addition to any promissory notes. |
| Hard Oil Finish | A varnish giving the effect of a rubbed-in oil finish but producing a hard surface; any interior architectural varnish with a moderate luster. |
| Hard Tile | A term used in the tile trade to designate types of tile, such as ceramic, glass mosaic, or marble tile, over which the tile trade has jurisdiction, as compared to resilient tile. |
| Hard Water | Water with an excessive mineral content. |
| Hard-Burned | Clay products which have been fired at high temperatures to near vitrification, generally producing relatively low absorption and high compressive strengths. |
| Hardboard | A very dense panel product, usually with at least one smooth face, made of highly compressed wood fibers; consolidated under heat and pressure, and having a density factor of approximately 50 to 80 pounds per cubic foot. |
| Hardboard Door | A door constructed of compressed wood fibers. |
| Hardboard Panel | Flat sheet material of fibers consolidated under heat and pressure in hot press. |
| Hardboard Panel Siding | Panel siding made of hardboard. |
| Hardboard Soffit | Hardboard finish material covering the underside of a part or member. |
| Hardboard Underlayment | Flat sheet material of hardboard placed over subflooring to provide smooth and even surface to receive finish floor covering. |
| Hardener | Curing agent; promoter; and catalyst used in making and finishing concrete. |
| Hardening | The gain of strength of plaster, mortar, or concrete after setting; see Set. |
| Hardhat 1 | A safety helmet of metal or plastic worn by workers on a construction site. 2. A construction worker who wears such a hat. |
| Hardness | 1. A property of a material that resists indentation. 2. Of water, the quantity of dissolved minerals, such as calcium and magnesium compounds. |
| Hardpan | Hard, tight soil; a hard layer that may form just below plow depth on cultivated land. |
| Hardscape | The non-organic elements of a landscape development, such as walls, paving, fences, and lighting standards. |
| Hardstand | A hard surfaced area for parking an airplane. |
| Hardwall | 1. Base coat plaster. 2. Regionally the term differs; in some cases it refers to sanded plaster, while in others to neat. |
| Hardware | All of the "metal" fittings that go into the home when it is near completion. For example, door knobs, towel bars, handrail brackets, closet rods, house numbers, door closers, etc. The Interior Trim Carpenter installs the "hardware". |
| Hardware Cloth | Steel wire mesh, usually galvanized, commonly 1/8-, 1/4-, or 1/2-inch mesh. |
| Hardwood Dimension Lumber | See Dimension Stock. |
| Hardwood Plywood & Veneer Association (HPVA) | 1825 Michael Faraday Drive, PO Box 2789, Reston, Virginia 22090-0789, (703) 435-2900. |
| Hardwood Plywood Manufacturer's Association (HPMA) | PO Box 2789, Reston, Virginia 22090, (703) 435-2900. |
| Hardwood Plywood Panel | Plywood with face plies manufactured from hardwood species such as cherry, oak, birch, ash, walnut, maple, gum, mahogany, or teak. |
| Hardwoods | Generally one of the botanical groups of trees that have broad leaves in contrast to the conifers or softwoods. The term has no reference to the actual hardness of the wood |
| Hardy Cross Method | See Moment Distribution. |
| Harmon Hinge | A hinge designed to swing a door into a pocket at a right angle with the frame. |
| Harsh | Refers to an asphalt mix that is difficult to compact and handle. |
| Harsh Mortar | A masonry mortar that is hard to spread under the trowel, usually because of a lean ratio of cement paste to aggregates. |
| Hasp Assembly | A fastener for a door or lid consisting of a hinged metal strap that fits over a loop and is secured by a pin or padlock. |
| Hatch | A hinged or removable cover in a floor or roof which permits ventilation or the passage of persons or objects. |
| Hatch, Roof | See Roof Hatch. |
| Hatchet | A multi-purpose short handled hand tool with a head suitable for alternative use as a hammer or axe; the convex head configuration to properly dimple the nail and the hatchet blade used to cleave and adjust framing and wallboard edges to fit, or as a jack |
| Hatchway | An opening giving access usually by ladder to a lower space like a cellar. |
| Haul Resistance | The distance measured along the most direct practical route between the center of the mass of excavation and the center of mass of the fill as finally placed; the distance material is moved. |
| Haul, Station Yards of | Station Yards of Haul. |
| Haunch | An extension, knee like protrusion of the foundation wall that a concrete porch or patio will rest upon for support. |
| Hawk | A metal square with a wooden handle at the center, used by a plasterer or tilesetter, to temporarily hold mortar or plaster; commonly, a rubber pad fits over the handle and covers that portion of the metal hawk that would come in contact with the hand. |
| Hazard insurance | Protection against damage caused by fire, windstorms, or other common hazards. Many lenders require borrowers to carry it in an amount at least equal to the mortgage. |
| Hazardous Waste | A material or substance characterized by a propensity to be unhealthy, toxic, or dangerous. |
| Hazardous Wiring | All wiring except that which conforms with all applicable laws in effect at the time of installation and which has been maintained in good condition and is being used in a safe manner. |
| HB | Hose Bibb. |
| Head | 1. The operative part of a tool. 2. The flattened part of a nail. 3. The upper horizontal part of a door, window, or other opening. 4. The pressure produced by a difference in elevation of two points in a body of fluid. 5. The top part of a column or pill |
| Head Flashing | The exterior flashing installed at the head of a door, window, or other opening. |
| Head Friction | Head required to overcome friction of the interior surface of a conductor and between fluid particles in motion. |
| Head Joint | See Butt Joint, 4. |
| Head Pressure | Pressure in the condensing side of a refrigerating system. |
| Head Pressure Control | Pressure-operated control which opens electrical circuit if high-side pressure becomes too high. |
| Head Velocity | Height of fluid equivalent to its velocity pressure in a flowing fluid. |
| Head, Pop-Up | See Pop-Up Head. |
| Head, Service | See Service Head. |
| Head, Static | See Static Head. |
| Head, Total Static | See Total Static Head. |
| Headcutting | The action of an upstream moving waterfall or locally steep channel bottom with rapidly flowing water through an otherwise placid stream. These conditions often indicate that a readjustment of a stream's discharge and sediment load characteristics is taki |
| Header | (a) A beam placed perpendicular to joists and to which joists are nailed inframing 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). |
| Header | 1. Length of pipe or vessel to which two or more pipe lines are joined carries fluid from a common source to various points of use; a manifold. 2. The pipe that runs across the top or bottom of an absorber plate, gathering or distributing the heat transfe |
| Header Bond | A brick bond that will show only headers on the face or surface of a wall; each header would be divided evenly over the header underneath it. |
| Header Course | A brick bond in which a course made up of headers only. |
| Header High | The height up to the top of the brick course that is directly under a header course. |
| Header, Ceiling | A joist perpendicular to and supporting ceiling joists. |
| heading | The top of a curtain, drapery, valance, or balloon shade, finished with tape, ties, rings, or other treatments, which hangs from a rod or pole. Headings range from simple, unpleated tabs to handmade pleats backed by hooks. They are often made using decora |
| heading tape | Ready-made gathering tape that is attached to the top of a curtain to create a particular heading. |
| Headlap | The minimum distance, measured at 90 degrees to the eave along the face of a shingle or felt as applied to a roof, from the upper edge of the shingle or felt, to the nearest exposed surface. |
| Headroom | The clear space between the floor line and ceiling, as in a stairway. |
| Headwall | A wall, usually constructed of concrete or masonry, that is placed at the inlet side of a drain or culvert to protect fill from scouring, undermining, or to divert flow. |
| Headwall, Removal | The act or process of demolition and removal of a headwall. |
| Healing Power | The ability of a glaze to heal surface blemishes during firing. |
| Hearing | A proceeding conducted by a judge or arbitrator who receives evidence about a dispute. |
| Hearsay | Evidence of an event that the witness did not personally perceive. |
| Heart Rot | Any rot characteristically confined to the heartwood; it generally originates in the living tree. |
| Hearth | The inner or outer floor of a fireplace, usually made of brick, tile, or stone. |
| Heartwood | The wood extending from the pith to the sapwood, the cells of which no longer participate in the life processes of the tree; heartwood may contain phenolic compounds, gums, resins, and other materials that usually make it darker and more decay resistant t |
| Heat | 1. The condition of being hot. 2. A form of energy arising from the random motion of the molecules of bodies, which may be transferred by conduction, convection, or radiation. |
| Heat Exchanger | A device for the transfer of heat from one medium to another. |
| Heat Intensity | Heat concentration in a substance as indicated by the temperature of the substance through use of a thermometer. |
| Heat Lag | The time it takes for heat to travel through a substance heated on one side. |
| Heat Leakage | Flow of heat through a substance. |
| Heat Load | Amount of heat, measured in BTUs or watts, which is removed during a period of 24 hours. |
| Heat Loss | The heat lost from a building through conduction, convection, and radiation as well as through air infiltration and ventilation systems. |
| Heat meter | An electrical municipal inspection of the electric meter breaker panel box. |
| Heat of Compression | Mechanical energy of pressure changed into energy of heat. |
| Heat of Fusion | Heat released from a substance to change it from a liquid state to a solid state; the heat of fusion of ice is 144 BTUs per pound (151.9 joules). |
| Heat of Hydration | The thermal energy given off by concrete, masonry, or gypsum as it cures. |
| Heat of Repression | 1. Process by which oxygen and carbohydrates are assimilated by a substance. 2. When carbon dioxide and water are given off by a substance. |
| Heat Pipe | A method of heat recovery from exhaust air in which a coil has a partition wall dividing the coil face into two sections; this system has no moving parts and relies on the slope of the coil to operate, sloping down from the cold end to the hot end. |
| Heat Pump | A combination heating and cooling device. In the winter it extracts heat from air as cold as 20 degrees, and in the summer it works in reverse to become an air conditioner. |
| Heat Recovery | The extraction of heat from a source not primarily designed to produce heat. |
| Heat Rough | Work performed by the Heating Contractor after the stairs and interior walls are built. This includes installing all duct work and flue pipes. Sometimes, the furnace and fireplaces are installed at this stage of construction. |
| Heat Sensor | A battery operated or hard wired mechanical/electrical device that either makes a loud noise or flashes a light when raised air temperature is detected; for use as a substitute for a smoke detector in locations that might have ambient smoke such as in kit |
| Heat Sink | A substance or device for the absorption and dissipation or recovery of heat in connection with a passive solar heating system. |
| Heat Storage | A device or medium that absorbs collected solar heat and stores it for periods of cloudy or cold weather. |
| Heat Strengthened Glass | Glass that has been strengthened by heat treatment, though not to as great an extent as tempered glass. |
| Heat Time | In multiple-impulse welding or seam welding the time during which the current flows during any one impulse. |
| Heat Transfer | Movement of heat from one body or substance to another; heat may be transferred by radiation, conduction, convection, or a combination of these three methods. |
| Heat Trim | Work done by the Heating Contractor to get the home ready for the municipal Final Heat Inspection. This includes venting the hot water heater, installing all vent grills, registers, air conditioning services, turning on the furnace, installing thermostats |
| Heat Wheel | A method of heat recovery from exhaust air in which both the intake and exhaust ducts are connected to the wheel. |
| Heat-Affected Zone | That portion of the base metal which has been altered by the heat of welding, cutting, or brazing. |
| Heat-Set Nylon | Nylon fiber which has been heat treated to retain a desired shape. |
| Heat/Smoke Vent | A vent or chimney forming a passageway for expulsion of vent gases from gas-burning units to the outside air. |
| Heater | Any heat-producing appliance or unit, such as a furnace. |
| Heater Duct | The conduit in a heating system that conveys warmed air throughout a building or structure. |
| Heater, Electric | See Electric Heater. |
| Heater, Unit | See Unit Heater. |
| Heater, Water | See Water Heater. |
| Heating Coil | An element where heat is transferred to an air stream; the heating medium may be steam, hot water, or electrical. |
| Heating Control | Device which controls the temperature of a heat transfer unit. |
| Heating load | The amount of heating required to keep a building at a specified temperature during the winter, usually 65° F, regardless of outside temperature. |
| Heating Value | Amount of heat which may be obtained by burning a fuel; usually expressed in BTUs per pound, BTUs per gallon, or calories per gram. |
| Heavy Bodied Oil | A high viscosity oil. |
| Heavy Centered Pattern | Spray pattern having most paint in center, less at edges. |
| Heavy Duty Pavement | Pavement designed for heavy traffic volumes and heavy loads. |
| Heavy Duty Tile | Tile suitable for areas where heavy pedestrian traffic is prevalent. |
| Heavy Soil | A fine grained soil made up largely of clay or silt. |
| Heavy Timber | Construction requiring noncombustible exterior walls with a minimal fire-resistance rating of two-hours, laminated or solid interior members, heavy plank, or laminated wood floors and roofs. |
| Hectare | A unit of land area equaling 10,000 square meters or 2.471 acres. |
| Heel | 1. The point at the end of a truss where the top and bottom chords intersect. 2. See Steel Square. |
| Heel cut | A notch cut in the end of a rafter to permit it to fit flat on a wall and on the top, doubled, exterior wall plate. |
| Heel, Rafter | The end or foot that rests on the wall plate. |
| Heeling In | Temporary planting of trees and shrubs. |
| Hegeman Grind Gauge | Proprietary instrument for measuring smoothness of pigment dispersion in liquid paint. |
| Height | The dimension measured at right angles to the direction of the thickness and length of a masonry unit, the vertical dimension, as used in a wall. |
| Helmet | A protective device used in arc welding for shielding the face and neck; a helmet is equipped with a suitable filter glass and is designed to be worn on the head. |
| Hemihydrate | A hydrate containing half a molecule of water to one of the material forming the hydrate; used to describe the form of calcined gypsum generally used for plaster. |
| HEPA | High Efficiency Particulate Arrestance; see HEPA Filter. |
| HEPA Filter | High-Efficiency Particulate Air Filter; such filters are rated to trap at least 99.9% of all particles 0.3 microns in diameter or larger. |
| Heritage Miniblinds | Contract aluminum miniblind made by Bali. |
| Hermetic Compressor | Compressor which has the driving motor sealed inside the compressor housing; the motor operates in an atmosphere of the refrigerant. |
| Hermetic Motor | Compressor drive motor sealed within same casing which contains the compressor. |
| Hermetic Seal | An airtight seal. |
| Hermetic System | Refrigeration system which has a compressor driven by a motor contained in the compressor dome or housing. |
| Heroic Scale | A statue of colossal size or proportions. |
| herringbone | A twill weave, usually wool or tweed, achieved by alternating the diagonal pattern within the cloth. It is suitable for upholstery. |
| Herringbone Blocking | Wood blocking between studs set at a slight angle in alternate directions in adjacent stud spaces, the angle making it possible to drive the blocks in tightly between studs. |
| Herringbone Bond | Bricks laid in a zigzag fashion representing a herringbone pattern. |
| Herringbone Floor | A floor covering made up of rows of parallel lines with adjacent rows slanting in reverse directions. |
| Hertz (Hz) | A measurement of the frequency of vibration of sound measured in cycles per second; one cycle per second equals one Hertz. |
| Hessian | See Burlap. |
| Heteropolymer | The result of Heteropolymerization. |
| Heteropolymerization | See Polymerization. |
| Heuristic | By trial and error and experiment rather than by science. |
| Hew | To fell, chop, or shape with an axe |
| Hex | 1. Hexagon. 2. Hexagonal. |
| Hex Nut | A six-sided, short metal nut with a threaded hole for receiving a rod or threaded bolt. |
| Hexagon | A polygon of six sides. |
| Hg | Mercury. |
| HI | Hydraulic Institute. |
| Hickey | A tool for bending pipe, conduit, and reinforcing bars. |
| Hiding Bond | Ability of a paint to hide or obscure the surface on which it is applied; degree of opacity of a pigment or paint. |
| High Boiling Solvent | A solvent with an initial boiling point above 302° F. (150° C.) such as diacetone alcohol or cellosolve acetate. |
| High Build | Producing thick dry films per coat. |
| High Calcium Lime | A type of lime containing principally calcium oxide or hydroxide and not more than 5% magnesium oxide or hydroxide. |
| High Chair Reinforcing | A chair-shaped device used to hold steel reinforcement off of the bottom form of a slab while the concrete is being poured. |
| High Early Strength Cement | Cement that develops strength more quickly than ordinary cement, typically will be as strong at 3 days and 7 days as normal cement would in 7 days and 28 days; alumina cement. |
| High Flash Naphtha | Aromatic solvent having a high flash point, minimum 113° F, 45° C. |
| High Frequency Curing | See Radio Frequency Curing. |
| High Joint | See Crown, 1. |
| High Lift Grouting | A method of construction in which concrete block units may be laid the entire height of the wall before grouting; this method of construction requires special inspection. |
| High Magnesium Lime | A type of lime containing more than 5% magnesium oxide or hydroxide. |
| High Pressure Gauge | Instrument for measuring pressures in range of 0 psi to 500 psi (0 kg/cm2to 3.52 kg/cm2). |
| High Pressure Steam Curing | See Autoclave Curing. |
| High Rate Sand Filter | A sand filter designed for flows in excess of five gallons per minute per square foot, but not in excess of 20 GPM per square foot. |
| High Relief | Sculptural relief in which at least half of the circumference of the modeled form projects. |
| High Side | Parts of a refrigerating system which are under condensing or high-side pressure. |
| High Strength Bolt | A bolt designed to connect steel members by clamping them together with sufficient force that the load is transferred between them by friction. |
| High Tension | High Voltage. |
| High Voltage | Electrical power of over 600 volts. |
| High Voltage Cable | Cable manufactured to withstand high-voltage. |
| High Voltage Circuit | Any circuit having a difference of potential of more than six hundred volts, or seven hundred fifty volts where specified in certain regulations, between any two conductors of the circuit. |
| High Wall | Undisturbed soil or rock bordering a cut; a face which is being excavated, as distinguished from spoil piles. |
| High-Pressure Boiler | Boiler furnishing steam at pressures of 15 pounds per square inch gauge or higher (1.05 kg/cm2). |
| High-Pressure Cut-Off | Electrical control switch operated by the high-side pressure which automatically opens electrical circuit if too high a pressure is reached. |
| High-Rise | A multi-storied building with elevators. |
| High-Side Float | Refrigerant control mechanism which controls the level of the liquid refrigerant in the high-pressure side of mechanism. |
| High-Vacuum Pump | Mechanism which can create a vacuum in the 1000 to 1 micron range. |
| Highbay Lighting | A lighting system located high above work or floor level. |
| Highest and Best Use | The use of land that will produce the highest future net income. |
| Highlight | A smooth area, noticeably different from the normal surface. |
| Highlighting | Making certain parts of finished project appear lighter than other parts. |
| Highlights | A light spot, area, or streak on a painted surface. |
| Highway Demolition | The destruction and removal of a public road. |
| Hinge | 1. A joint fixing the relative position of the ends of two or more structural members, but permitting their relative rotation. 2. A piece of door hardware that permits the opening and closing of a door by joining the door to the jamb with a flexible devic |
| Hinge Stile | The door stile to which the hinges are installed as distinguished from the lock stile. |
| Hip | A roof with four sloping sides. The external angle formed by the meeting of two sloping sides of a roof. |
| Hip | The diagonal intersection of planes in a hip roof. |
| Hip Rafter | A structural member of a roof forming the junction of an external roof angle or, where the planes of a hip roof meet. |
| Hip Roof | A roof consisting of four sloping planes that intersect to form a pyramidal or elongated pyramid shape; a roof which slopes up toward the center from all sides, necessitating a hip rafter at each corner. |
| Hippodamian Plan | Greek plan, derived its name from Hippodamos, with grid city blocks, informal organization of public spaces and facilities within the grid matrix; better known examples are the Ionian cities of Ephesus and Miletus, 5th Century BC. |
| Hod | A portable trough for carrying plaster, mortar, and bricks, fixed crosswise on top of a pole and carried on the shoulder. |
| Hoddability | A term descriptive of the ease with which a plaster mortar may be handled with a hod or hawk, dependent upon flow characteristics and angle of repose of the mortar. |
| Hoe | A long handled tool with a thin flat metal blade for cultivating, weeding, and mixing. |
| Hog Ring | A heavy galvanized wire staple applied with a pneumatic gun which clinches it in the form of a closed ring around stud, rod, pencil rod or channel. |
| Hoist, Industrial | See Industrial Hoist. |
| Hoistway | Any shaftway, hatchway, well hole, or other vertical opening or space in which an elevator or dumbwaiter is designed to operate. |
| Hold Harmless | See Indemnification. |
| Hold Out | Ability to prevent soaking into substrate. |
| holdback | An ornamental wood or metal shape attached to the wall on either side of a window near a curtain or drapery, which is looped over the holdback when open. |
| Holder, Door | See Door Holder. |
| Holding Period | In the manufacture of concrete products, the period between completion of casting and the introduction of additional heat or the steam curing period. |
| Holdover Tenant | A tenant that does not vacate the property at the end of a lease term. |
| Hole | 1. An opening or perforation in a material. 2. A pit in the ground. |
| Holiday | 1. In roofing, a skipped area of liquid applied roofing. 2. In painting, unintentional missing of an area of surface being painted. |
| Holland | Medium-weight cloth made from linen or cotton. The non- fraying edges make it ideal for roller shades. |
| Hollow Block | Concrete blocks that can be filled with insulation or reinforced and grouted. |
| Hollow Clay Tile | A tile building material manufactured in a variety of sizes and forms, used for both exterior walls and partitions. |
| Hollow Column | A vertical column constructed so as to create an air space within. |
| Hollow Concrete Masonry | Concrete masonry units that are manufactured with open cores, such as ordinary concrete blocks. |
| Hollow Core Door | A flush hardwood or plywood door glued to a skeletal framework with the interior remaining void or honeycombed. |
| Hollow Core Slab | A precast concrete slab element that has internal longitudinal cavities to reduce its self-weight. |
| Hollow Masonry Unit | A masonry unit whose net cross-sectional area in any plane parallel to the bearing surface is less than 75% of its cross-sectional area measured in the same plane. |
| Hollow Metal Door | A hollow core door constructed of sheet metal that has been channel-reinforced; the core is often filled with some type of lightweight material. |
| Hollow Metal Frame | A sheet metal door frame with reinforcing at the hinges and strikes. |
| Hollow Wall | A wall built of solid masonry units laid in and so constructed as to provide an air space within the wall. |
| Hollow-Back | Removal of a portion of the wood on the unexposed face of a wood trim member to more properly fit any irregularity in bearing surface. |
| Hollow-Core Construction | A panel construction with faces of plywood, hardboard, or similar material bonded to a framed-core assembly of wood lattice, paperboard rings, or the like, which support the facing at spaced intervals. |
| Hollow-Tube Gasket | Sealing device made of rubber or plastic with tubular cross-section. |
| Home run (electrical) | The electrical cable that carries power from the main circuit breaker panel to the first electrical box, plug, or switch in the circuit. |
| Homestead | 1. A tract of land granted by the U.S. upon recording, improving, and cultivating the property. 2. A residence. 3. A home and adjoining land occupied by a family; this can be exempt from judgment up to a certain amount by filing a Declaration of Homestead |
| Hone | A honing stone. |
| Honey combs | The appearance concrete makes when rocks in the concrete are visible and where there are void areas in the foundation wall, especially around concrete foundation windows. |
| Honeycomb Core | A sandwich core material, for doors or building panels, constructed of thin sheet materials or ribbons formed to honeycomblike configurations. |
| Honeycomb shade | Cellular insulating shade manufactured by most major manufacturers. From the side the shade looks like stacked honeycombs. |
| Honeycombing | Checks, often not visible at the surface, that occur in the interior of a piece of wood, usually along the wood rays. |
| Honing Stone | A fine-grit stone for sharpening cutting tools. |
| Hood, Exhaust | See Exhaust Hood. |
| Hood, Range | See Range Hood. |
| Hook | A semicircular bend in the end of a reinforcing bar to develop bond, and thus anchorage. |
| Hook Knife | A special curved knife used primarily for cutting resilient floor coverings; also called a Linoleum Knife. |
| Hook Stick | An implement that is curved or bent for holding, catching, or pulling. |
| Hook Strip | Strip of wood, plastic, or metal secured to a wall surface to provide a mounting surface for hooks, such as coat hooks or key hooks. |
| Hook Wire | A hook implement that is curved or bent for holding, catching, or pulling. |
| hook-and-loop tape (velcro) | Self-gripping tape that comes in sew-on and self-adhesive forms. It is mainly used to attach a cornice or valance to the front edge of the valance shelf; the ìhookî side is stuck to the shelf, the ìloopî side is sewn to the valance or cornice. |
| Hooke's Law | Stress and strain are proportional up to the elastic limit of the material. |
| Hoop | Circular shaped pieces of steel reinforcing bar. |
| Hopped-Up Mud | Mortar mixed with an accelerator. |
| Hopper | Deep water basin with all four sides sloping for diving. |
| Hopper Window | A window whose sash pivots on an axis along the sill, and that opens by tilting toward the interior of the building. |
| Horizon | The line at which the earth and sky appear to meet. |
| Horizontal | Parallel to the horizon. |
| Horizontal Angle | An angle in a horizontal plane. |
| Horizontal Application | The application of gypsum board with the long dimension at right angles to the framing members; also referred to as perpendicular. |
| Horizontal Branch | A branch drain in the DWV system that extends from a soil, waste stack, or building drain to the fixture trap; it may or may not have vertical sections or branches off of it which receive discharge from one or more fixture drains and carry this discharge |
| Horizontal Broken Joints | A style of laying tile with each course offset one-half its length. |
| Horizontal Fixed Position | The position of a pipe joint wherein the axis of the pipe is approximately horizontal and the pipe is not rotated during welding. |
| Horizontal Forces | Any lateral loads imposed on a structure, including those caused by wind or earthquake forces. |
| Horizontal Hardboard Siding | Horizontal siding made of hardboard often used as clapboards on a house. |
| Horizontal Rolled Position | In pipe welding, the position of a pipe joint wherein welding is performed in the flat position by rotating the pipe. |
| Horizontal Shaft Mixer | A mixer having a stationary cylindrical mixing compartment, with the axis of the cylinder horizontal, and one or more rotating horizontal shafts to which mixing blades or paddles are attached. |
| Horizontal Siding | Linear horizontal material, usually overlapping, used as an exterior surface or cladding for an exterior framed wall. |
| Horizontal Wood Siding | Linear horizontal wood material, usually overlapping, used as an exterior surface or cladding for an exterior framed wall. |
| Horizontally Laminated Wood | Laminated wood in which the laminations are so arranged that the wider dimension of each lamination is approximately perpendicular to the direction of load. |
| Horn | The extension of a stile, jamb or sill. |
| Horsepower | 1. A unit of electrical power in the U.S. equal to 746 watts. 2. In the English gravitational system, 550 foot-pounds of work per second. |
| Hose bib | An exterior water faucet (sill cock). |
| Hose Bibb | Bibbcock. a water spigot or faucet with its nozzle threaded or coupling attached to accept a hose; also spelled Hose Bib; also called a Wall Hydrant or a Sill Cock. |
| Hose Reel | A round device upon which a hose is wound for easy dispensing. |
| Hospital Bed | A piece of furniture found in a hospital where patients recline, lie and sleep. |
| Hospital Cubicle | A small partitioned space or sleeping compartment in a hospital. |
| Hospital Divider | A movable partition in a hospital to create privacy. |
| Hospital Equipment | Apparatus or implements used in hospital applications. |
| Hospital Faucet | A water faucet that is controlled by feet to help eliminate the spread of germs by hands. |
| Hospital Panel | A partition in a hospital which divides areas into smaller spaces. |
| Hospital Stretcher | A narrow, movable bed with collapsible legs and wheels used for transporting patients, often from an ambulance to a hospital. |
| Hospital Wardrobe | A cabinet installed in a hospital patient room to store the patient's clothes; usually matches any other cabinet or furniture in the room. |
| Hot Aggregate Storage Bins | Bins that store the heated and separated aggregates prior to their final proportioning into the mixer. |
| Hot Gas Bypass | Piping system in refrigerating unit which moves hot refrigerant gas from condenser into low-pressure side. |
| Hot Gas Defrost | Defrosting system in which hot refrigerant gas from the high side is directed through evaporator for short period of time and at predetermined intervals in order to remove frost from evaporator. |
| Hot Junction | That part of thermoelectric circuit which releases heat. |
| Hot Lacquer Process | Process where heat is used instead of volatile thinner to reduce the consistency of lacquer; hot lacquer can be applied with a higher percentage of solids than room-temperature lacquer. |
| Hot Mix | Refer Asphalt. |
| Hot Mud | Mortar mixed with an accelerator; also called Hot Stuff. |
| Hot Plate, Laboratory | See Laboratory Hot Plate. |
| Hot Spray | Spraying material heated to reduce viscosity. |
| Hot Stuff | 1. Mortar mixed with an accelerator; also called Hot Mud. 2. Hot bitumen. |
| Hot Tub | Refers specifically to a hydrotherapy unit normally constructed of wood designed and assembled in the traditional manner of tubs or casks, with side and bottoms formed of separate boards and the whole shaped to join together by pressure of the surrounding |
| Hot Water Circulating Loop System | A piping arrangement in which hot water is constantly circulated in a loop from which individual plumbing fixtures are fed. |
| Hot Water Dispenser | A device used to heat and deliver small quantities of water. |
| Hot Water Heating System | System in which water is circulated through heating coils. |
| Hot Water Storage Tank | A tank that receives heated water and holds it for future distribution. |
| Hot Wire | 1. The live wire, carrying electric current, as opposed to the neutral or ground. 2. Resistance wire in an electrical relay which expands when heated and contracts when cooled. |
| Hot Wire Relay | See Thermal Relay. |
| Hot-Laid Plant Mixture | Plant mixes that must be spread and compacted while at an elevated temperature; to dry the aggregate and obtain sufficient fluidity of the asphalt (usually asphalt cement), both must be heated prior to mixing, hence the term hot-mix. |
| Hot-Water Boiler | A boiler furnishing hot water at pressures not more than 30 pounds per square inch gauge (2.12 kg/cm2) or steam at pressures not more than 15 pounds per square inch gauge (1.06 kg/cm2). |
| Hotel | A building containing an establishment providing lodging and meals. |
| hourglass curtain | A sash curtain tied at the center to create a ìwaistedî effect. |
| House | A building for human habitation. |
| House Drain | The horizontal part of the drainage system which connects the DWV piping within the structure to the sanitary sewer or private sewage treatment equipment. |
| House Drainage System | Complete system of piping used for carrying away waste water and sewage; also called Building Drainage System. |
| House Paint, Outside | Paint designed for use on the exterior of buildings, fences and other surfaces exposed to the weather. |
| House Sewer | The piping that takes the soil and waste water from the building drain and conveys it to the public sewer or private sewage disposal system; also called Building Sewer. |
| House Trap | Located at the point at which the house drain leaves the building, designed to hold a quantity of water that prevents gasses from the sewer system from entering the building. |
| Housed Joint | A joint in which a piece is grooved to receive the piece which is to form the other part of the joint. |
| Housing | A groove cut at any angle with the grain and partway across the piece; used for framing stair risers and treads. |
| Howe Truss | A standard peaked roof truss configuration where the vertical web members and the bottom chord are in tension while the sloping web members and the top chord are in compression. |
| HP | High Pressure. |
| HP Sodium Lamp | A high-pressure sodium vapor lamp that produces a wide-spectrum yellow light. |
| HPMA | Hardwood Plywood Manufacturer's Association. |
| HPVA | Hardwood Plywood & Veneer Association. |
| Hub | 1. A surveyor's bench mark; used as a starting point for measuring elevations and horizontal distances. 2. The enlarged end of a hub and spigot cast-iron pipe. |
| Hub Union | A pipe fitting used to join two pipes without turning either pipe. |
| Hue | Color. |
| Human Relations | A behavioral aspect of management -- handling of personnel and the consideration of each problem from the employee's point of view; the success or failure of the business often depends on the relationship between management and personnel. |
| Humidification | The addition of moisture to air, thereby increasing the latent heat. |
| Humidified Bond | In gypsum wallboard, the ability of the surfacing paper to resist delamination from the core under extremely high humidity conditions. |
| Humidifier | A device designed to increase the humidity within a room or a house by means of the discharge of water vapor. They may consist of individual room size units or larger units attached to the heating plant to condition the entire house. |
| Humidistat | Electrical control which is operated by changing humidity. |
| Humidity | The amount of water vapor in a given volume of air. |
| Humidity Ratio | The weight of water vapor per unit weight of dry air; also called Specific Humidity. |
| Hump Joint | See Crowned Joint. |
| Humus | Decayed organic matter; a dark fluffy swamp soil composed chiefly of decayed vegetation; also called peat. |
| Hung Slab | A nonstructural concrete slab having no bearing on walls, being totally supported from above by an overhead structural element. |
| Hunter Douglas | Blind and shade fabricator, with unique and innovative products. Products include Duette honeycomb shades, Luminette, Silhouette, Country Wood Blinds, Everwood, Woodmates, Decor miniblinds, Celebrity miniblinds, Lightline miniblinds, and others. (#2 Parkw |
| Hurricane | A tropical cyclone with winds over 74 miles per hour; usually accompanied by rain, thunder, and lightning. |
| Hurricane clip | Metal straps that are nailed and secure the roof rafters and trusses to the top horizontal wall plate. Sometimes called a Teco clip. |
| Hut | A small or temporary dwelling of simple construction. |
| Hutment | A collection of huts. |
| HVAC | Heating, Ventilation, and Air-Conditioning system. |
| HVAC Control | An apparatus that controls a heating, ventilation, and air conditioning system. |
| HW | Hot Water. |
| Hydrant | 1. A discharge pipe with a valve and threaded outlet from which water may be drawn from a water main; a faucet. 2. Fire hydrant; fire plug. |
| Hydrant Removal | The act or process of removing an old hydrant. |
| Hydrant, Wall | See Wall Hydrant. |
| Hydrate | 1. A chemical combination of water with another compound or an element. 2. Hydrated Lime. |
| Hydrated Lime | Calcium hydroxide, a dry powder obtained by treating quicklime with water; also called Hydrate. |
| Hydration | The process of adding water to a substance. |
| Hydraulic Cement | A type of portland cement that will harden or set under water. |
| Hydraulic Elevator | A lifting device powered by pressured fluid. |
| Hydraulic Excavator | A digging machine powered by pressured fluid. |
| Hydraulic Gradient | The slope of the surface of open or underground water. |
| Hydraulic Institute (HI) | 9 Sylvan Way, Parsnippany, New Jersey 07054, (201) 267-7772. |
| Hydraulic Lift | An elevating device powered by pressured fluid. |
| Hydraulic Spraying | (See Airless) Spraying by hydraulic pressure. |
| Hydraulics | 1. The science of the conveyance of liquids through pipes. 2. The branch of physics having to do with the mechanical properties of water and other liquids in motion. |
| Hydrocarbon | An organic compound containing only carbon and hydrogen; fuels such as natural gas, gasoline, and coal contain hydrocarbons. |
| Hydrocarbon Resins | Obtained by catalytic polymerization of petroleum fractions. |
| Hydrochloric Acid | A solution of the colorless gas hydrogen chloride that is a strong corrosive irritating acid, used in dilute form for cleaning portland cement paste from brick or stone work. |
| Hydrofluoric Acid | An aqueous solution of hydrogen fluoride that is a weak poisonous acid that attacks silica and silicates, used for finishing and etching glass. |
| Hydrojet | A fitting which blends air and water creating a high velocity, turbulent stream of air enriched water. |
| Hydrojet Booster Pump System | A system whereby one or more hydrojets are activated by the use of a pump which is completely independent of the filtration and heating system of the spa. |
| Hydrology | The science of the properties of the earth's water, on the surface, subsurface, and atmospheric, and its movement in relation to land. |
| Hydrometer | A device for measuring the density of liquids. |
| Hydronic | Heating system which circulates a heated fluid, usually water, through baseboard coils by means of a circulating pump which is controlled by a thermostat. |
| Hydronic Heating System | A system that circulates heated water through convectors to heat a building or space. |
| Hydrophilic | Having an affinity for water; capable of uniting with or dissolving in water. |
| Hydrophobic | Having antagonism for water; not capable of uniting or mixing with water. |
| Hydroponics | The process of growing plants in sand, gravel, or liquid, without soil and with added nutrients. |
| Hydrostatic Pressure | Pressure exerted by standing water. |
| Hydrostatic Relief Valve | A valve installed in the main drain of the swimming pool, sometimes in other areas as well; when the pool is full, the valve is closed; when pool is empty, it is opened to allow ground water to flow into the pool; this prevents the pool from floating, whi |
| Hydrous | Containing water. |
| Hygrometer | An instrument, consisting of a dry bulb thermometer and a wet bulb thermometer, for measuring the humidity of the atmosphere or of a gas; also called a Wet and Dry Bulb Hygrometer or a Psychrometer. |
| Hygroscopic | 1. Tendency to absorb water. 2. Ability of a substance to absorb and release moisture and change physical dimensions as its moisture content changes. 3. A synthetic rubber (chlorosulfonated polyethylene) often used with neoprene in elastomeric roof coveri |
| Hyperbolic Paraboloid | Double curved surface which can be generated by sliding a straight line along two other lines which are skew to each other but lie in parallel planes. |
| Hyperbolic Paraboloid Shell | A concrete roof structure with a saddle shape. |
| Hypocenter | The point below the epicenter at which an earthquake actually begins; also called the Focus. |
| Hypotenuse | The side of a right triangle which is directly opposite the right angle itself. |
| Hypothecate | To pledge property for repayment of a debt without giving up title or possession of the property |