Term Description
Drying time

The time required for the loss of volatile components so that the material will no longer be adversely affected by weather conditions such as dew, rain or freezing.
Dual-level drain

In waterproofing, an outlet or other device with provisions for drainage at both the wearing surface and waterproofing membrane levels used to collect and direct the flow of runoff water from a horizontal slab.
Durability

The ability to withstand physical, chemical or environmental abuse.
Dynamic load

Any load that is non-static, such as a wind load or moving live load.
Eave

The lower edge of a sloping roof; that part of a roof that projects beyond the wall.
Edge venting

The practice of providing regularly spaced or continuously protected (louvered or otherwise shielded) openings along a roof edge or perimeter, used as part of a ventilation system to dissipate heat and moisture vapor.
Efflorescence

An encrustation of soluble salts, commonly white, deposited on the surface of stone, brick, plaster or mortar; usually caused by free alkalies leached from mortar or adjacent concrete as moisture moves through it.
EIFS

See "exterior insulation and finish system."
EIP

See "ethylene interpolymers."
Elasticity

The property of a body that causes it to tend to return to its original shape after deformation (such as stretching, compression or torsion).
Elastomer

A macromolecular material that returns rapidly to its approximate initial dimensions and shape after substantial deformation by a weak stress and subsequent release of that stress.

Elastomeric coating

A coating that is capable of being stretched at least twice its original length (100 percent elongation) and recovering to its original dimensions.
Elastomeric waterproofing

A liquid-applied single- or multi-component waterproofing membrane that is seamless, flexible and capable of being stretched at least twice its original length (100 percent elongation) and recovering to its original dimensions.
Electro-galvanized

A method of application of corrosion-resistant zinc coatings for fasteners.
Electronic Leak Detection (ELD)

Using electrical conductance measurement methods to locate leaks in exposed or covered waterproof membranes installed over conductive substrates.
Elongation

The ratio of the extension of a material to the length of the material prior to stretching. Usually, elongation is expressed as a percentage of the original length.
Embedment

(1) The process of pressing/positioning a felt, aggregate, fabric, mat or panel into hot bitumen or adhesive to ensure contact at all points; (2) the process of pressing/positioning granules into coating in the manufacture of factory-prepared roofing, such as shingles.
Embrittlement

The loss of flexibility or elasticity of a material.
Emissivity

(1) Infrared emissivity is a measure of the ability of a surface to shed some of its absorbed heat (in the form of infrared radiation) away from the surface; emissivity is expressed as a percentage or a decimal factor; (2) the ratio of radiant energy emitted from a surface under measurement to that emitted from a black body (the perfect emitter and absorber) at the same temperature.
Emulsion

(1) A bituminous emulsion is a mixture of asphalt and water with uniform dispersion of the bitumen or water globules, usually stabilized by an emulsifying agent (clay or soap) or system; (2) a relatively stable mixture of two immiscible liquids held in suspension by small amounts of emulsifiers.
End lap

The distance of overlap where one ply, pane or piece extends beyond the end of the immediately adjacent underlying ply, panel or piece.
Envelope (bitumen-stop)

A continuous membrane edge seal formed at the perimeter and at penetrations by folding the base sheet or ply over the plies above and securing it to the top of the membrane. The envelope prevents bitumen seepage from the edge of the membrane.
EPDM

Ethylene propylene diene M-class rubber, also called ethylene propylene diene terpolymer. See "ethylene propylene diene terpolymer."
Epoxy

A class of synthetic, thermosetting resins that produce tough, hard, chemical-resistant coatings and adhesives.
EPS

See "expanded polystyrene."

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