GRAVEL

Loose fragments of rock used for surfacing built-up roofs, in sizes varying from 1/8" to 1 3/4".

GROUT OR GROUTING

A cement mortar mixture commonly used to fill joints and cavities of masonry. On roof decks, the joints between many types of precast roof deck slabs are grouted with cement grout.

GUTTER

Metal trough at the eaves of a roof to carry rain water from the roof to the

downspout.

GUTTER STRAP

Metal bands used to support the gutter.

GUY WIRE

A strong steel wire or cable strung from an anchor on the roof to any tall slender

projection for the purpose of support.

GYPSUM

A hydrated sulfate of calcium occurring naturally in sedimentary rock. In roofing,

a type of lightweight deck made from this pulverized rock.

HATCH

An opening in a deck; floor or roof. The usual purpose is to provide access from

inside the building.

HIP ROOF

A roof which rises by inclining planes from all four sides of a building.

INCOMPATIBILITY

Descriptive of two or more materials which are not suitable to be used together.

INSIDE DRAIN

A roof drain positioned on a roof at some location other than the perimeter. It

drains surface water inside the building through closed pipes to a drainage system.