Investigation and Repair of a Leaking Travertine-Faced Precast Concrete Façade

Façade leaks had been ongoing for a number of years at an office building in Maryland despite previous replacement of all the perimeter sealants, installation of drip caps at the window heads, and sealing numerous cracks in the wall panels. The building façade consists of fixed windows, set flush with the exterior wall panels. The 5″ thick wall panels are comprised of precast concrete with a ¾″ thick travertine veneer. Cracks in the travertine were a concern for two reasons: water leakage through the travertine was bypassing the perimeter sealants and leaking into the building, and there was a potential for cracked travertine pieces to detach from the precast concrete backup. The Owner’s goals were to retain the existing wall panels, substantially reduce water infiltration, and improve the appearance of the crack repairs. This paper describes how digging deeper into the source of the water infiltration and understanding the Owner’s requirements resulted in a solution that addressed the problems and achieved the Owner’s goals. Investigation of the wall panels and window frames revealed that water entering cracks in the travertine travelled along the stone-concrete interface, down into the window frames, and building interior. Prototype repairs, watertesting, and adhesion tests led to a successful repair protocol that included recessing new metal flashings over the window heads, pinning the travertine, routing, and sealing cracks flush with the exterior surface, and applying a breathable coating to the wall panels.