EIFS Terms

Adhesive
A material used to attach the thermal insulation board to the substrate.

Aesthetic Reveal
A term that is being phased in to replace the term “aesthetic joint.”
An aesthetic reveal is a groove cut into EPS board and serves as a
decoration and/or to provide a starting or stopping point for finish coat
application.

Applicator
An independent contractor who installs EIFS systems. An applicator is
instructed by EIFS manufacturers in the handling and use of their
products but have no contractual relationship with the manufacturer.

ASTM
American Society for Testing and Materials. An independent organization
that is involved with setting standards and practices for all materials,
including those used in EIFS. ASTM standards are currently being
developed specifically for EIFS construction.

Backer Rod
Material that is placed into a joint receiving sealant to set the
depth, sealant configuration and prevent three-sided adhesion.

Base Coat
The initial, wet state material, either factory or field-mixed, that is
used to encapsulate and embed reinforcing mesh. Some base coats may be used as an adhesive to attach EPS board to a substrate. The base coat is the system’s primary weather barrier.

Class PB EIFS
A polymer-based system applied over EPS board. The base coat ranges in thickness depending on the number of fiberglass reinforcing layers
encapsulated in the base coat over the entire surface. The base coat is
then covered with primer, if required by the specifications, and a finish
available in a variety of textures and colors.

Class PI EIFS
A polymer-based system applied over polyisocyanurate board attached
over opening framing or solid substrates. The base coat ranges in thickness
depending on the number of fiberglass reinforcing layers encapsulated
in the base coat over the entire surface, The base coat is then covered with a primer, if required by the specifications, and a finish coat available
in a variety of textures and colors

Class PM EIFS
A polymer-modified, mechanically fastened EIF system with base coats
ranging in thickness from 1/4 to 3/8 inches nominal. The base coat is covered with a primer, if required by the specifications, and a finish coat, which is available in a variety of textures and colors. These systems use trim accessories.

Cracks
Breaks in the surface lamina of an EIFS. They are usually caused by
internal stresses in the wall system greater than the strength of the lamina.
Some common causes are unlapped mesh, gaps between insulation boards, adhesive between insulation boards, design errors (no expansion joint where one belongs) and concentrated stresses at un-reinforced corners of the openings and projections throught the system.

Deflection
The amount of movement in a wall as a result of the load applied to it.
Class PB EIFS are designed to be applied to substrates that meet L/240
(height of unsupported wall span/240) maximum allowable deflection.
Note: Meeting design criteria and calculation of deflection are the
responsibility of the building designer.

EIFS
Exterior Insulation Finish System (pronounced eefs)

EIMA
EIFS Industry Members Association

Expansion Joints
A structural separation between building elements that allows
independent movement of abutting elements without damage to the assembly. In EIFS, an expansion joint, as opposed to an aesthetic reveal, is a break that goes through the thermal insulation board and lamina.

Finish Coat
A polymer-based material that provides color and texture when troweled
or sprayed over reinforced base coat.

Flashings
Corrosive resistant material used to drain moisture to the exterior of
the wall assembly.

Isolation Joint
A joint provided around penetrations through the EIFS System, such as
window and door openings, scuppers, etc. it may or may not incorporate
flashings and is sealed with the appropriate back rod and sealant.

Lamina
Composite of base coat, reinforcement, and finish coat.

Mechanical Fasteners
Corrosion resistant component used to attach the insulation board to the substrate or framing member.

Primer
Primers are sometimes applied to improve the water resistance of
cementitious base coats.

Reinforcing Mesh
A specially woven fiberglass mesh embedded in the base coat to
strengthen the system. Reinforcing mesh is available in various weights to achieve different levels of impact resistance.

Sealant
A material that has the adhesive and cohesive properties to form a
barrier to prevent water and/or air intrusion.

Substrate
Surface to which the EIFS is applied.

Terminations
Any place an EIFS ends. Terminations can be window or door openings,
the bottom or top of a wall or both sides of an expansion joint. In any
case, all terminations must be totally encapsulated with base coat and mesh
and a sealant or flashing with appropriate back rod installed to prevent
water infiltration.

Texture
Any surface appearance as contrasted to a smooth surface.

Thermal Insulation Board
A system component of a specific type and density that functions to
reduce heat flow through a wall and also serves as the surface to receive the base coat. Some examples of thermal insulation boards include expanded polystyrene (EPS), extruded polystyrene and polyisocyanurate board.

Wrap
To protect the exposed edges of thermal insulation board.