Specifications include, but are not limited to: 1. Opaque Exterior Wall Assemblies The exterior opaque wall assemblies consist of a direct-applied fiber cement cladding system, including face-nailed panels in the field and blind-nailed lap siding between window stacks that were painted with an acrylic finish coat. The fiber cement cladding was installed over asphaltimpregnated building paper and paper-faced gypsum wall sheathing without a dedicated drainage plane between the cladding and the weather-resistive barrier membrane. Fiber cement trim was screwed into the substrate along transitions between the fiber cement cladding and adjacent building enclosure systems. Many of the fasteners used to anchor fiber cement trim were overdriven, causing widespread cracking, and resulting in direct water leakage pathways into the wall assembly with subsequent risk for damage. No adequate sheet metal backing was installed behind fiber cement panel and lap siding joints. As a result, the cladding assembly relies solely exterior sealant applications for continuity of the water shedding surface and preventing water intrusion. We observed many areas where these seals along panel joints have failed, causing pathways for water leakage with subsequent damage. Asphalt-saturated kraft (assumed Grade-D, 60 minute) building paper was used as the primary weather resistive barrier membrane. This material is not suitable to resist long-term exposure to water intrusion and showed signs of deterioration. In addition, this material is not typically installed or detailed in a manner that provides a dedicated air barrier, which in turn results in uncontrolled air leakage through the enclosure. We observed many areas with evidence of water staining and organic growth throughout all building areas as evidence of ongoing condensation as a result from this interior air leakage. Gypsum wall sheathing with an organic paper facing was used as the primary exterior sheathing material. This material is not suitable for exterior wall applications, as the paper facer deteriorates if exposed to water. This results in a high risk for organic growth, as well as deterioration of the gypsum core. We observed many areas with widespread water staining and organic growth on the exterior sheathing plane as a result. Sheet metal flashing assemblies used along base of wall conditions and window interfaces did not have adequate end dams to prevent water leakage into the wall assembly. We observed several areas with evidence of water staining as a result of water leakage into the assembly due to this condition. Some horizontal sheet metal flashing assemblies used along horizontal transitions did not have a properly extended vertical leg to allow for integration with the weather-resistive barrier membrane for limited cross-cavity drainage. Localized flashing assemblies were not integrated with the weather-resistive barrier membrane, preventing cross-cavity wall drainage. The base of wall areas had pressure-treated furring strips in vertical orientation to create a rainscreen cavity between the fiber cement cladding and the sheathing plane. This assembly is more adequate as it provides a dedicated drainage path and better protects the underlying substrates from prolonged exposure to water (e.g., snow drift). However, the fiber cement cladding system is extended near grade level without proper closure along the base to protect it from snow buildup and freeze-thaw conditions. We observed areas with existing damage to the cladding assembly at these areas. Localized sheet metal flashing assemblies along base of wall conditions were installed directly against concrete sidewalks without separation. This is not an adequate installation and creates a risk for flashing corrosion and subsequent water leakage path to the interior 2. Exterior Windows The in-service vinyl window frames showed widespread evidence of deterioration throughout both buildings. The dark bronze exterior finish is not advised for climate zones with high annual insolation, as it absorbs a significant amount of heat, exposing the window frame to large mechanical stresses from thermal expansion and contraction. We observed evidence of stress cracking at window frame miter joints and other system components, which can likely be attributed to excessive thermal cycling. These conditions create direct water intrusion pathways into the window system that can cause leakage and overwhelm the systems’ internal drainage pathways. In addition, we observed evidence of widespread IGU failure, likely a result of the aforementioned mechanical stresses onto the window frames. This thermal cycling and resultant movement impose additional strain on the hermetic seals at the perimeter of the IGUs. The window assemblies do not have an adequate back dam at the window sill to create a backstop for water intrusion (e.g., cracked frames), making it vulnerable to leakage. In addition, the lack of proper interior sheet metal angles do not allow for a proper formation of an interior air seal, which can result in condensation and increased water leakage potential during high wind conditions. From discussions with on-site facility staff, we understand that occupants experience significant drafts and air leakage around window penetrations. Interior sealant was applied in numerous areas in an attempt to mitigate this, however, these modifications have been ineffective, likely due to improper air sealing of the original installation. We observed many areas where the existing exterior rubber gaskets around operable sashes were significantly deteriorated, causing additional pathways for both air and water ingress. In addition, many exterior sealant joints around window perimeters have failed, resulting in direct water leakage paths into the wall assembly with subsequent risk for damage.
