What does EIFS stand for?

EIFS (pronounced eefs) is an acronym for Exterior Insulation and Finish System. An EIFS consists of five basic components:

 

• Insulation board, made of polystyrene or polyisocyanurate foam.
• A specially formulated adhesive and/or mechanical attachment of the insulation to a substrate.
• Glass fiber reinforcing mesh.
• A durable, water-resistant base coat, which is applied on top of the insulation that functions as the weather barrier.
• An attractive and durable finish coat — typically using acrylic co-polymer technology — which is both colorfast and crack-resistant.

2.

What is the difference between PM and PB EIFS?

"PM" refers to Polymer Modified and "PB" refers to Polymer Based. Class PB EIFS typically use adhesively fastened expanded polystyrene (EPS) insulation, and glass fiber reinforcing mesh embedded in a nominal 1/16 inch (1.6mm) base coat. PB EIFS can incorporate additional layers of base coat and reinforcing mesh to achieve higher impact resistance. An EIFS finish coat is used over the base coat.

 

PB EIFS represents the majority of EIFS used in North America.

 

Traditionally, Class PM EIFS use extruded polystyrene insulation (XEPS), and a thick, cementitious base coat applied over mechanically attached glass fiber reinforcing mesh. The system has joints similar to traditional stucco. PM EIFS have evolved to include different insulation materials and base coats. A standard finish is used although an elastomeric finish can be used to bridge hairline cracks that may occur in the thicker base coat.

3.

What is the maximum thickness allowed for foam shapes to achieve architectural treatments such as accent bands and cornices?

The national model building codes generally limit foam thickness to a 4-inch maximum. However, precedence exists for using thicker expanded polystyrene foam insulation when acceptable to local authorities having jurisdiction.