Sarasota Floridian Moisture Related Distress Investigation

Walker Consultants performed a structural engineering investigation of moisture-related distress at the still under construction apartment buildings at the Sarasota Floridian development. It consists of two three-story still under construction apartment buildings. The wood framed structures are built on a reinforced concrete slab-on-grade foundation.

The structures were exposed to a long period of heavy rains related to a tropical storm. As a result, water intrusion into the structures occurred when their envelopes (exterior walls and roofing systems) were not yet watertight per their design specification. Construction was halted due to concerns about the structural integrity of the oriented strand board (OSB) sub floor sheathing in the structures.

During the investigation, the team found edge swelling and delamination of OSB sub floor panel edges. The edge swelling of the OSB sub floor panels created uneven surfaces at butt joints along panels and waviness at the panel butt joints with partial restraining at nail locations. This swelling and dimensional change due to failure of adhesive bonds and development of voids within the composite material had caused delamination and checking within the thickness of the OSB panels. This resulted in permanent loss of strength, unevenness, and misalignment of the flooring.

Exposure to moisture and swelling of the panels caused the nails used for securing the OSB panels to the floor truss joists to countersink and rust, the extent of which also created a reduction in structural capacity of the panels. Exposure to moisture caused debonding of the glue between the OSB sub floor panels and the floor truss joists. These conditions created long-term structural strength and serviceability issues for the floor systems of the structures.

Walker’s investigation provided vital information to the client that was instrumental in securing a resolution to the builder’s risk claim.