Solving water infiltration issues at Hanley Administration Building

The Hanley Administration Building was built in 1968. The three-story building has a basement that extends beyond the exterior walls of the first level. An approximately 38,000 square foot concrete plaza around the building's perimeter covers the basement. Throughout the building's lifespan, water has infiltrated through the plaza surfaces into the basement despite numerous projects completed in attempt to stop the leaks. The Capital Development Board hired Fehr Graham to investigate the chronic water infiltration, identify causes, make recommendations to waterproof the plaza, develop a project budget and prepare plans and specifications to implement the recommendations.

The engineering team investigated the water infiltration using record plans and exploratory methods to determine deficiencies in the waterproofing system and developed a design to correct those deficiencies. The design included removing concrete surfaces and the ineffective waterproofing and installing a subsurface drainage system, including modifying surface drains to collect subsurface runoff and installing a hot fluid applied waterproofing and flashing system. Our designs included specifications for replacing the plaza's thin concrete surfaces, perimeter drainage systems and sidewalks.

The waterproofing system has proven effective since there have been leaks post-construction for the first time in the lifespan of the building.

AT A GLANCE
» Established construction phase budget.
» Performed design and construction services for waterproofing deck and walls.
» Prepared designs for removal and replacement of concrete and walkways.
» Completed designs and specifications for the installation of the waterproofing, drains and flashing.