Eave: a projecting edge of a roof that extends beyond the supporting wall.

 

Eave Height: the vertical dimension from finished grade to the eave.

 

Eaves-Trough: see Gutter.

 

ECH: polyepichlorohydrin, commonly referred to as epichlorohydrin. (See Epichlorohydrin.)

 

Edge Stripping: membrane flashing strips cut to specific widths used to seal/flash perimeter edge metal and the roof membrane.

 

Edge Venting: the practice of providing regularly spaced or continuously protected (e.g., louvered) openings along a roof edge or perimeter, used as part of a ventilation system to dissipate heat and moisture vapor.

 

Efflorescence: the formulation of crystalline deposits, generally whitish in color, on the surface of stone, brick, concrete, or other masonry surface when moisture moves through and evaporates on the masonry. May also be caused by free alkalies leached from mortar, grout, or adjacent concrete.

 

Elasticity: the property of matter by virtue of which it tends to return to its original size and shape after removal of a stress or force which caused a deformation.

 

Elastomeric Coating: a coating system which, when fully cured, is capable of being stretched at least twice its original length (100% elongation) and recovering to its original dimensions.

 

Elongation: the ability of a material (e.g., roofing membrane) to be stretched by the application of a force.

 

Embedment: (1) the process of installing or pressing-in a reinforcement felt, fabric, mat or panel uniformly into bitumen or adhesive; (2) the process of pressing granules into coating during the manufacture of factory-pre-pared roofing; (3) the process whereby ply sheet, aggregate, or other roofing components settle into hot- or cold-applied bitumen via the force of gravity.

 

Embrittlement: the loss of flexibility or elasticity of a material. The transition of a flexible material to a brittle state.

 

End Lap: the distance of overlap where one ply, panel, or piece extends beyond the end of the immediately adjacent underlying ply, panel, or piece.

 

Envelope (Bitumen-Stop): a continuous edge seal formed at the perimeter and at penetrations by extending the base sheet or one ply of felt beyond the edge of the membrane field plies. After all overlying field plies or insulation are in place, the extended ply is turned back onto the membrane and adhered. The envelope is intended to prevent bitumen seepage from the edge of the membrane.

 

EPDM: Ethylene Propylene Diene Monomer (See also Ethylene Propylene Diene Terpolymer.)

 

Epichlorohydrin (ECH): a synthetic rubber including two epichlorohydrin based elastomers. It is similar to and compatible with EPDM. ECH is typically used in lieu of EPDM when enhanced resistance to animal fat or other oils is needed.

 

Equiviscous Temperature (EVT): the temperature at which a bitumen attains the proper viscosity for built-up membrane application.

 

Ethylene Propylene Diene Terpolymer (EPDM): designated nomenclature of ASTM for a terpolymer of ethyl-ene, propylene, and a diene. EPDM material is a thermosetting synthetic elastomer.

 

EVT: Equiviscous Temperature

 

Exhaust Ventilation: air that is typically vented or exhausted from the roof cavity, typically through vents installed on the upslope portion of the roof. For example, with most steep-slope roof assemblies exhaust vents are typically located at or near the ridge.

 

Expansion Cleat: a cleat designed to handle thermal movement of the metal roof panels.

 

Expansion Joint: a structural separation between two building elements that allows free movement between the elements without damage to the roofing or waterproofing system.

 

Eyebrow: a dormer, usually of small size, whose roof line over the upright face is typically an arched curve, turning into a reverse curve to meet the horizontal at either end. Also, a small shed roof projecting from the gable end of the larger, main roof area.

 

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