Hi-Tech Project Profile: Settlement of Concrete Isolation Pad under Boiler


A 36’ x 12’ isolation concrete slab supporting a 100,000 lbs. boiler had experienced settlement. Cracks were observed in the slab wall, as well as beneath and around the base of the boiler inside the building. A previous stabilization effort, consisting of a low pressure grout injection, was conducted beneath portions of the boiler slab. The settlement, however, continued to the point where the boiler had to be shut down. The goal was to stabilize the boiler, but not lift the boiler.


After soils testing verified the weak soils, a plan was put in place to stabilize the weak soil zones with expanding structural polymer. The polymer was injected in various locations and depths under the footprint of the isolation slab. In various locations we encountered standing water in the soil. The polymer used was excellent for remediating the water and densifying the compromised soil in these saturated areas.  


Our lasers read positive upward influence on the isolation pad as well as the surrounding concrete areas. A laser on the boiler indicated only a 1/32” lift, achieving the goal of stabilizing, but not lifting the boiler. No excavation, and minimal disruption to facility operations.

Consider geopolymer injection for:

  • Sinkhole Remediation
  • Infrastructure Sealing
  • Stormwater Management Solutions
  • Concrete Slab Stabilization