Biology Lab Floor Lifting

Biology Building Floor Lifting–Polyurethane Grouting, Virginia


Part of the footprint of the biology building at a university was built over a basement & steam tunnels, the other portion of the first floor was a slab. The backfill material placed against the 16′ tall basement walls during construction consolidated, causing the floor slab to settle, and a trip hazard to develop.

The settlement affected the joint between the slab on grade & slab over basement through a professor’s office, three hallways, a bathroom, lecture room, conference room, bioterrorism lab, robotics lab, computer lab & a lab storage room. Multiple layers of surface patch material had been applied over time to smooth the transition between the slabs, and the slab was continuing to move. Settlement in some areas exceeded 1 inch.


Given the sensitivity of the biological materials and associated equipment in the lab rooms, the repair had to be quiet, clean & with minimal downtime. There were many pieces of lab equipment resting on the affected floors which could not be moved, including specimen refrigerators, vent hood assemblies, storage cabinets, and lab benches.

Dozens of computers used for research were mounted within a few feet of the affected floor joint. The repair process had to accommodate the computers being left in place to avoid the disruption associated with dismantling the computers and their accompanying lab equipment.

Numerous raceways and utility conduits both in and below the floor required special care in material placement.


Polyurethane grouting to stabilize and lift the affected areas of slab floor. The structural engineer who originally consulted on the project had recommended grout injection. However, the owner determined that grout injection would have been phenomenally disruptive to the use of the space and continuity of the research being done in the work areas.

Since foam jacking is dust free, fast and quiet, it was chosen as the most appropriate repair. A pre-construction meeting was arranged for all of the professors whose labs were affected, to determine which equipment needed to stay in place and which could be moved out of the way to provide access to the injection locations. Due to the extensive previous surface patching, selective flooring removal was proposed by the general contractor.


CJGeo lifted and stabilized nearly 350 linear feet of joint through the work area in fewer than 12 working hours. The large lab which the work area passed through remained in operation during the work, and the hallways, bathroom and other areas were able to remain in use with minimal disruption throughout the work period.

None of the subslab or encased utilities were affected, and flooring restoration was able to start the day after the lifting was completed.