BSC investigated a 25-year old precast wall warehouse that was experiencing moisture and staining issues at the office space walls. The moisture issues originated at the exterior walls above the 2nd floor office ceiling, and were ascribed to seasonal condensation/frosting issues that then melted.
Examining the building revealed that although the 2nd floor walls were well insulated (with 2” rigid foam), the walls above the suspended ceiling were uninsulated, providing a cold condensing surface of the bare precast panels. Interior-generated moisture (from occupancy) could easily reach the cold surface by duct leakage and air leakage through the suspended ceiling. This behavior was evident in exterior infrared thermography; the greater heat loss of the space above the ceiling made the exterior surface noticeably warmer.
Given that the space above the ceiling is effectively indoors, BSC provided remediation recommendations of insulating the interior of the exposed precast walls in a condensation-resistant manner. Options included the use of closed-cell spray foam (with an intumescent coating for fire requirements) or a rigid polyisocyanurate rated to be left exposed. Installation and air sealing specifics were also provided.