REI Construction Services, Inc. managed the engineering services and construction for the removal and replacement of the powerhouse deck of a large hydroelectric dam facility. Previous field investigations identified failing expansion and sealant joints, failing wall and penetration / curb flashings and the deterioration of the existing waterproofing membrane and concrete topping slab that was allowing water intrusion in numerous areas.

The project scope included the removal of the existing concrete topping slab and waterproofing membrane and the installation of a temporary waterproofing membrane providing moisture protection during the removal of the topping slab. After exposing and repairing several areas of the existing structural concrete slab, a new hot applied rubberized asphalt waterproofing membrane was installed. A protection layer and drainage panel was installed over the new waterproofing membrane. New drain assemblies were installed, the lightning protection system grounding cabling was replaced and new expansion and sealant joints and flashings were installed prior to the pouring of the new concrete topping slab.

A traffic coating was applied in designated areas to allow vehicular access onto the deck where needed. Due to the waterproofing membrane being installed beneath 8” of concrete; locating a potential membrane breach in the future could result in a costly and time consuming endeavor. During the design phase of the project, an electronic leak detection system was included in the project specifications. This cutting-edge technology utilizes a low voltage current over the membrane surface and can detect a pinhole breach in the membrane that is invisible to the naked eye within minutes.

The project was completed on schedule with zero injuries occurring during the project duration.