Exterior insulation and finish systems (EIFS) are intended to act as a barrier against water penetration and not allow water to penetrate through the system to the backup wall construction and leak into the interior of the building. Recent investigations of EIFS on several buildings including a 15-year-old building that does not have any windows and buildings that are about five to ten years old that have windows, have revealed that failure of the joints between the EIFS and the windows and other openings in the EIFS, and at terminations in the EIFS, is the primary cause of water leakage and water damage in EIFS on buildings. Other conditions that cause water leakage in EIFS, to a lesser degree, include cracks in the EIFS, delamination of the base coat from the rigid insulation, and window deficiencies.
To minimize water leakage in buildings with EIFS, the backup wall, EIFS, windows, doors and all other wall components and the joints between them should be designed and constructed to act as a facade system consistent with the barrier behavior of EIFS or as a unified facade system with a coordinated secondary line of defense against water penetration, rather than as separate elements joined together; and the design and construction of the substrate to which the EIFS is attached should be the responsibility of the EIFS manufacturer and contractor. Recommendations on the design of a unified facade system with a secondary line of defense against water penetration are provided for consideration.