Tracing Persistent Water Infiltration to a Failed Window Sealant Detail

Trinity United Church of Christ is a multi-story church in Jasper, Indiana, with a history dating to 1898 and a sanctuary constructed in 1966. Technical Assurance was engaged to investigate recurring water infiltration along the west elevation of the clerestory roof area below the sanctuary’s stained-glass windows. Water infiltration was visible from the building interior during the initial evaluation.

The sanctuary incorporates multiple roof configurations and materials, including low-slope EPDM, asphalt shingles, and standing-seam metal roofing. Because the reported leakage occurred near the transition between the clerestory windows and roof area, determining the actual entry point required evaluating conditions beyond the roof surface alone.

Using Diagnostic Testing to Isolate the Leak Source

Technical Assurance performed controlled spray testing to evaluate the conditions surrounding the clerestory windows and reproduce the reported water infiltration. Testing revealed that the exterior sealant at the clerestory window frames had failed.

Further evaluation identified the underlying cause: the original frame and glazing sealant had not been removed before remedial sealant was applied. Installing new material directly over the existing sealant ultimately resulted in failure of both layers and allowed water to enter the building.

Providing a Targeted Path to Remediation

With the source of the leakage identified, Technical Assurance recommended complete removal of the existing sealant around the affected clerestory windows, proper preparation and cleaning of the surfaces, and installation of an appropriate new sealant system.

By identifying the specific failure mechanism rather than broadly replacing roof or enclosure components, Technical Assurance provided the owner with the information needed to obtain pricing from local contractors and move forward with a targeted repair.