Water Intrusion in Community Library Building

case_leg_waterintrusionA concrete frame community library building in the New York Metropolitan area underwent major renovation work to add an additional story to the building.  Water intrusion problems were noticed as soon as the building was occupied, and continued despite various repair efforts.  A dispute arose between the Library, architect, contractors, construction manager, and insurers regarding the cause of the water intrusion, required building repairs, and cost-sharing, which led to the matter going to Mediation to determine an amicable cost sharing settlement. We were asked to determine the cause of the water intrusion problems, describe repair work needed to correct the problems, and estimate costs for the repair work.

Our investigation found that water intrusion was caused by improper window flashing, which resulted from a confluence of causes including inadequate detailing, lack of control over construction sequencing, and improper window installation.  We prepared a detailed estimate of repair costs by determining material quantities involved and application of unit costs for labor, materials, and equipment.  Unit costs were derived from a national construction cost database adjusted for local conditions, and then with confirmation by local specialty contractors.  Library management and other involved parties used our analysis and cost estimate to reach a cost-sharing agreement among the responsible parties.

We prepared design and bidding documents for the required repair work.  This involved very carefully staged removal of masonry materials to allow installation of new flashing materials.  The project scope was expanded to include rehabilitation of several single ply roofing membranes resulting in extension of roofing warrantees for an additional ten years.