FAQs

Design Considerations


Design Considerations

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 are the maximum deflection criteria for the EIFS PB system?

L/240.

 

Do EIFS have a fire rating?

EIFS alone do not have a fire rating. Testing has been performed to confirm that the fire resistance of an already rated wall assembly is maintained and is not reduced by the addition of an EIFS.

 

Should EIFS be applied below grade?

No. Building codes have criteria for minimum separation of siding materials from grade. EIFS manufacturers generally require that EIFS be maintained a minimum 8 inches above finished grade to ensure code compliance. At Concrete patios, walks, etc. the systems should be held a minimum of 8 inches above the finished surface.

 

Is mechanical attachment of EIFS recommended to resist high wind loads?

No. In general, adhesive attachment of EIFS to sound supporting construction provides superior wind load resistance in comparison to mechanical attachment. It is important in an adhesively attached system that the supporting construction is free of surface damage, defects, or contamination. In the case of frame construction, sheathing must be attached with fasteners and fastener spacing that are capable of resisting wind loads.

 

What are the limitations for usage of EIFS in high wind load areas?

Independent testing has been performed to determine the ultimate strength of a manufacturer's adhesives to various substrates. The average tensile bond strength was determined to be approximately 20 psi, which converts to 2880 psf. It should be evident that adhesively applied EIFS provides bond strength well in excess of what is needed for virtually any projects. The design variables to achieve higher wind load resistance occur within the substrate system and are the responsibility of the project designer.

 

Is "greenboard" a suitable substrate for EIFS?

No. Gypsum wallboard in compliance with ASTM C 630, often referred to as "greenboard" (because it has a green paper facing on one side), is an interior wallboard commonly used in wet areas such as bathrooms. Suitable gypsum board substrates for EIFS are gypsum sheathing in compliance with ASTM C 1396 (formerly C 79), glass-mat gypsum sheathing in compliance with ASTM C 1177 (Dens-Glass Gold® or BPB GlassRoc), and gypsum fiber panels in compliance with ASTM C1278 (Fiberock® Brand, Aqua Tough™). The sheathing manufacturer's instructions should be followed with respect to handling and installation.

 

What determines the use and location of a vapor retarder in a wall assembly?

The selection and/or location of a vapor retarder is project specific based on numerous factors including climate, wall components, etc., and as such is a design consideration that is the responsibility of the design professional.