» High rise self standing walls - possess various load bearing capacities, fire resistant properties, water resistant properties, etc.
» Handicap Grab Bars - Handicap grab bars and handrails help create a safe environment for those with disabilities, the elderly, and people with limited mobility. This is
because persons with disabilities use handicap grab bars to maintain balance, transfer, and prevent falls.
» Hammerhead boom crane A heavy-duty lifting device that uses a tower-mounted horizontal boom that may rotate only in a horizontal plane.
» Hardboard A ver y dense panel product, usually with at least one smooth face, made of highly compressed wood fibers.
» Hardwood Wood from deciduous
(broadleaf) trees.
» Hawk A square piece of sheet metal with a perpendicular handle beneath, used by a plasterer to hold a small quantity of wet plaster and transfer it to a trowel for application to
a wall or ceiling.
» HDO See High-density overlay.
» Head The horizontal top portion of a window or door.
» Header In framed construction, a mem- ber that carries other perpendicular framing members, such as a beam above an opening in a wall or a joist supporting other joists
where they are interrupted by a floor opening. In steel construction, a beam that spans between girders. In ma- sonr y construction, a brick or other ma- sonr y unit that is laid
across two wythes with its end exposed in the face of the wall.
» Head jamb See Head.
» Head joint The vertical layer of mortar between ends of masonr y units.
» Hearth The noncombustible floor area outside a fireplace opening.
» Heartwood The dead wood cells in the center region of a tree trunk.
» Heat-fuse To join by softening or melt- ing the edges with heat and pressing them together.
» Heat of hydration The thermal energy given off by concrete or gypsum as it cures.
» Heat-strengthened glass Heat-treated glass that is not as strong as tempered glass, and that may not be used as safety glazing.
» Heat-treated glass Glass that is strength- ened by a heat treatment process; either heat-strengthened glass or tempered glass.
» Heaving The forcing upward of ground or buildings by the action of frost or pile driving.
» Heavy timber construction A type of wood construction made from large wood members and solid timber decking in a post and beam configuration; in the International
Building Code, buildings of Type IV HT construction, consisting of
heavy timber interior construction and noncombustible exterior walls, are con- sidered to have moderate
fire-resistive properties.
» High-density overlay (HDO) A heavy weight, resin-treated overlay applied to plywood panels to achieve a smoother, more durable face.
» High-lift grouting A method of con- structing a reinforced masonr y wall in which the reinforcing bars are embedded in grout in stor y-high increments.
» High-range sealant A sealant that is ca- pable of a high degree of elongation with- out rupture.
» High-range water-reducing admixture See
Superplasticizer.
» High-reactivity kaolin See Metakaolin. 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-volume fly ash concrete (HVFA concrete) A concrete in which a high percentage of cementing substance is fly ash rather than portland cement.
» Hip The diagonal intersection of planes in a hip roof.
» Hip rafter A roof rafter at the intersec- tion of two sloping roof planes. See also Common rafter.
» Hip roof A roof consisting of four slop- ing planes that intersect to form a pyrami- dal or elongated pyramid shape.
» Hollow brick Clay brick with up to 60 percent void area.
» Hollow concrete masonry Concrete ma- sonr y units that are manufactured with open cores, such as ordinar y concrete blocks.
» Hollow-core door A door consisting of two face veneers separated by an airspace, with solid wood spacers around the four edges. The face veneers are usually con- nected
by a grid of thin spacers within the airspace.
» Hollow-core slab A precast concrete slab element that has internal longitudi- nal cavities to reduce its self-weight.
» Hollow structural section (HSS) Hol- low steel cylindrical or rectangular shapes made to be used as structural members; also called structural tubing.
» Hook A semicircular bend in the end of a reinforcing bar, made for the purpose of anchoring the end of
the bar securely into the surrounding concrete.
» Hopper window A window whose sash pivots on an axis along or near the sill and that opens by tilting toward the interior of the building.
» Horizontal force A force whose direc- tion of action is horizontal or nearly hori- zontal. See also Lateral force.
» Horizontal reinforcing Steel reinforcing that runs horizontally in a masonr y wall in the form of either welded grids of small diameter metal rods or larger convention- al
reinforcing bars.
» Hose stream test A standard laborator y test to determine the relative ability of a building assembly to stand up to water from a fire hose after a specified period of fire testing.
» Hot-dip galvanizing A method of galva- nizing in which a steel member or assem- bly is dipped into a bath of molten zinc.
» Hot-rolled steel Steel formed into its final shape by passing it between rollers while it is ver y hot.
» Housewrap A synthetic sheet material with water-resistive and air-resistive prop- erties used as a substitute for asphalt- saturated felt or building paper to pro- vide a
protective layer in an exterior wall assembly.
» HSS See Hollow structural section.
» HVFA concrete See High-volume fly ash concrete.
» Hydrated lime Quicklime mixed with water, either in the factor y or on the job site; an ingredient in masonr y mortars, portland cement plaster, and gypsum plasters, to which
materials it imparts properties such as workability, bulk, and smoothness; chemically, calcium hydrox- ide; also called slaked lime.
» Hydration The process by which ce- ments combine chemically with water to harden.
» Hydraulic cements Cementitious ma- terials, such as portland cement or blast furnace slag, that harden by reacting with water and whose hardened products are not water
soluble. Nonhydraulic cements, such as lime, can also be mixed with poz- zolans to create cements with hydraulic properties.
» Hydronic heating system A system that circulates warm water through convectors to heat a building.
» Hydrostatic pressure Pressure exerted by standing water.Hygroscopic Readily absorbing and re- taining moisture.
» Hyperbolic paraboloid shell A concrete roof structure
with a saddle shape.
