Branch & Associates, Inc.


Expedition Station is a residential condominium located in an extreme mountain top environment. It was constructed from wood-framed premanufactured modules stacked on top of a steel and concrete base. It is clad with fiber cement siding nailed over a weather-resistant barrier on oriented strand board (OSB) sheathing. The building's windows are vinyl double-hung units that are often ganged into double or triple configurations.


After reviewing design documents, WJE engineers conducted infrared thermal scanning of the walls to locate wet areas and performed water leakage testing of windows and surrounding cladding. The engineers also inspected and documented as-built conditions at probe openings.

WJE determined—through water leakage testing—that the vinyl windows were not thermally welded where the jamb meets the sill, providing a water pathway into the building. They also found that the lack of end dams in the flashing contributed to deterioration of fiber cement siding. As part of the repair and rehabilitation phase of the project, all double-hung windows were replaced in the building, and WJE assisted the contractor in coordinating window installation; siding replacement; insertion of new end dams; sill flashings; and weather-resistant barrier tapes with the extant wall system. End dams in metal siding trim were also added to prevent deterioration of adjacent fiber cement siding.