A | B | C | D | E | F | G | H | I | J | K | L |
M | N | O | P | Q | R | S | T | U |V | W | X | Y | Z

Hand-tabbing
method of spot applying asphalt-based adhesive to shingles for securement and wind resistance.

Hardness
the relative resistance of a material to indentation.

Headlap
the distance of overlap measured from the uppermost ply or course to the point where it laps over the undermost ply or course.

Heat Aging
controlled exposure of materials to elevated temperatures over time.

Heat flow
the quantity of heat transferred to or from a system in a unit of time.

Heat seaming
the process of joining thermoplastic films, membranes, or sheets by heating and then applying pressure to bring both materials in contact with each other. (see Heat welding.)

Heat transfer
the transmission of thermal energy from a location of higher temperature to a location of lower temperature. This can occur by conduction, convection, or radiation.

Heat welding
method of melting and fusing together the overlapping edges of separate sheets or sections of polymer modified bitumen, thermoplastics or some uncured thermoset roofing membranes by the application of heat (in the form of hot air or open flame) and pressure. (see Heat seaming.)

Hem
the edge created by folding metal back on itself.

Hip roof
a roof that rises by inclined planes to form one or more hips.

Hip
the inclined external angle formed by the intersection of two sloping roof planes.

Hoist
a mechanical lifting device.

Holiday
an area where a liquid-applied material is missing or absent.

Honeycomb
voids left in concrete resulting from failure of the mortar to effectively fill the spaces among course aggregate particles.

Hot or Hot stuff
a roofing worker's term for hot bitumen.

Hue
the subjective perception of color such as red, yellow, green, blue, purple or some combination; white, black or gray possess no hue.

Humidity
the condition of the atmosphere with respect to water vapor. See relative humidity.

HVAC
heating, ventilating, and air conditioning equipment.

Hybrid roof covering
combination of two or more separate and distinct roof membranes; e.g., three ply smooth BUR and a modified bitumen cap.

Hydration
the chemical reaction by which a substance (such as Portland cement) combines with water, giving off heat to form a crystalline structure in its setting and hardening.

Hydrocarbon
an organic chemical compound primarily containing the elements carbon and hydrogen.

Hydrostatic pressure relief system
a system of perimeter and/or under slab drains used to regulate the hydrostatic pressure in the earth surrounding a below-grade structure.

Hydrostatic pressure
the pressure equivalent to that exerted on a surface by a column of water of a given height.

Hygroscopic
attracting, absorbing and retaining atmosphere moisture.

HypalonTM
a registered trademark of E.I. duPont de Nemours & Co., for "chlorosulfonated polyethylene" (CSPE). (see Chlorosulfonated polyethylene.)