Polyurethane Undersealing

Polyurethane Undersealing of Industrial Floor, Pittsburgh, Pennsylvania


Water seeped through cracks in break room, bathroom and maintenance shop inside of metalworking facility. Facility maintenance consultant identified drainage problems and water service leak as sources of water. Investigation holes drilled through floor revealed up to 30 inches of saturated, uncontrolled fill above shale. Voids up to 6 inches were present between the bottom of the floor and the top of the uncontrolled fill, and held standing water during site visit.

The concrete floor was generally intact, but had settled up to 1.3 inches. Buildout of the area, including multiple masonry walls, a kitchen and bathroom had been completed after settlement, and multiple hairline stair step cracks in masonry walls bearing on floor area indicated continued movement. Water coming through joints in floor had caused ceramic floor tiles over approximately 1,000 square feet to delaminate from slab.

The slab at the top of the exterior steps at the work area entrance had settled approximately 3 inches.


Due to the work schedule of the facility, work had to be completed without disrupting use of the facility with no downtime. Ideal time for completion was fewer than two days. Installation had to permit undisturbed use of break room/kitchen, bathroom and maintenance room without removing any fixtures, storage shelves, etc.


HIgh density polyurethane injection to fill voids below the floor and seal the bottom of slab joints which were allowing water to pass through slab. Foam jacking for lifting the settled slab at the top of the steps using.


After the chemical grouting was done , high density polyurethane undersealing was completed  and plural component polyurethane grouting was used to lift the settled step landing slab. The polyurethane injection was done in a few hours, without disrupting normal use of the area. After the polyurethane grouting was completed, the crew patched the injection holes with concrete, which was stained to match the color of the tile grout in the appropriate areas.