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About EIFS

FAQs: Flashing and Building Envelope Design


Exterior Insulation and Finish Systems (EIFS) used on a Building

Is flashing required with EIFS?

Yes. As with all wall claddings, flashing is an important component required by building codes. At points where water can enter the wall, flashing should be directed to the exterior face of the wall. Openings for windows and similar through-wall penetrations require jamb, head, and still flashing to direct water to the exterior face of the cladding.


What are the most common entry points for water in building envelope walls?

As with all claddings, the most common water entry points in a wall are through or around windows, transitions from roof to walls, and transition from wall claddings to doors and chimneys. This, coupled with improperly installed or missing flashing and sealants, can allow water to penetrate behind EIFS, or any other cladding, and into the wall cavity, where it can potentially cause moisture damage.


Is EIFS more vulnerable to damage from moisture intrusion than other wall claddings?

No. Moisture intrusion is a potential threat to durability of materials in all exterior wall construction, regardless of cladding type. Moisture intrusion should be avoided by following sound design and construction practices mandated by building codes.


Are EIFS permeable?

Yes, but depending on the manufacturer and the product selected, the EIFS vapor permeability may vary. When requested, the EIFS manufacturers can perform a Water Vapor Transmission Test for specific walls to evaluate the tendency for condensation to occur.


What is "EIFS with drainage"?

EIFS with drainage is conventional EIFS installed over a water-resistive barrier, with provisions (vertical drainage channels) for discharging of incidental water that may enter behind the insulation board. In the event of a breach of the EIFS, the drainage path for moisture exists behind the EIFS to drain water to the exterior.


Is a water-resistive barrier required prior to installing EIFS in residential construction?

EIFS manufacturers recommend the use of water-resistive barriers over moisture sensitive substrates to provide additional protection in the event of a component failure. Local building codes will stipulate whether this is a requirement or not.