Friday, July 27th, 2012
Written by: carmstrong
By Megan Danner, LEED AP
Multi-Family High Rise
Failing Barrier EIFS, northern flicker woodpeckers (Colaptes auratus)
Barrier EIFS failure allowing moisture intrusion and delamination of façade
Remove barrier EIFS system and replace with a hard coat stucco system.
After an EIFS panel fell off the uppermost floor of a senior housing high rise, SBSA’s staff was called out to investigate.
The original masonry building was constructed in 1965, and extensively remodeled in 1994, which included installing barrier EIFS cladding on approximately 30-percent of the building façade. Due to moisture intrusion behind these panels, they had become delaminated, which is why one of them fell off the building. In order to determine where this moisture was behind the EIFS cladding, SBSA performed an infrared analysis. Anomalies that appeared in the photos indicated a thermal differential around fenestrations, at woodpecker holes and at floor lines. SBSA concluded the thermal differentials were likely a result of moisture intrusion—indicating that the barrier system had failed.
The building envelope needed to be repaired, and SBSA was hired as the design professional of the design-build team with a general contractor, who provided construction for the repair of the building envelope. SBSA determined that replacing the current system with a moisture-managed EIFS system would solve the moisture intrusion problem, but not the woodpecker problem.
To stop the woodpeckers, a hard-coat stucco system—in lieu of EIFS—was installed, along with new windows, sheathing and weather-resistive barrier. SBSA considered the thermal loss from removing the EPS insulation and the risk of the future cladding material failing from woodpecker damage. The new windows provided a tighter assembly, which helped offset the heat loss through the cladding. At each floor line, SBSA incorporated weep mechanisms to direct any incidental moisture to the exterior of the system over shorter distances rather than allowing moisture to travel more than 10-stories before exiting.
Upon completion, the woodpeckers did return to test the new cladding system, but were immediately disinterested with the lack of the hollow sound.