| R-Value |
the resistance
to heat transfer of a material.
|
| Rake |
the sloped edge of a roof at
the first or last rafter. |
| Reflectivity |
the ability of the surface of
a material to reflect the infra red energy of a light
source. |
| Reglet |
a groove in a wall or other surface
adjoining a roof surface for use in the attachment
of counterflashing. |
| Reinforced Membrane |
a roofing or waterproofing membrane
reinforced with felts, mats, fabrics, or chopped fibers. |
| Relative Humidity |
the ratio of the weight of moisture
in a given volume of air vapor mixture to the saturated
(maximum) weight of water vapor at the same temperature,
expressed as a percentage. For example, if the weight
of the moist air is 1 pound and if the air could hold
2 pound of water vapor at a given temperature, the
relative humidity (RH) is 50 percent. |
| Reroofing |
the practice or applying new
roofing material over existing roofing materials. |
| Ridging |
an upward, "tenting" displacement
of a roof membrane, frequently occurring over insulation
joints, deck joints and base sheet edges. Generally
associated with improper application. (See picture
framing) |
| Roll Roofing |
the term applied to smooth surfaced
or mineral surfaced coated felts. |
| Roof Assembly |
an assembly of interacting roof
components (including the roof deck) designed to weatherproof
and, normally, to insulate a building's top surface. |
| Roof System |
a system of interacting roof
components (NOT including the roof deck) designated
to weatherproof and, normally, to insulate a building's
top surface. |
| Rubber |
a polymeric material, which,
at room temperature, is capable of recovering substantially
in shape and size after removal of force. |
