These comments are for general information only and are not intended to be relied upon as a guide for design, construction, or inspection of EIFS. Although every effort is made to ensure that this information is timely and correct, the responsibility remains with the designer, specifier, homebuilder, general contractor, and/or installer for specific applications. The specification, design, and construction of all EIFS must comply with local building codes and standards, applicable compliance reports and the individual manufacturer's system requirements. The successful performance of EIFS cladding is dependent upon the proper design and construction of the adjacent materials and systems of the structure.

 

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

 

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.

 

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.