Slab Foundation Repair

Slab Foundation Repair, Jacksonville, NC



Thomas V. Admay, P.E., Engineered Foundation Solutions, Durham, NC


Slab foundation of house settled, causing extensive racking of interior doors, and cracks in walls and floors. Soil boring indicated that up to 4 feet of uncontrolled fill material was placed below the floor slab during construction of the home. The soil study confirmed that the underlying virgin soil was of adequate strength, however the fill material placed to level the building pad (the lot had approximately 4 feet of fall across the width of the house) was improperly compacted. Construction debris was also encountered in the soil samples, indicating potential interference with helical slab pier installation.


Repair had to be performed quickly and with as little disruption to the homeowner as possible. Work was being completed as part of a new home warranty settlement, so repair had to meet or exceed expectations of homeowner, homeowner’s representative, warranty company, and their representatives. A leak in the sanitary sewer line below the floor also required attention to detail to avoid entry of lifting foam into the sanitary lines.

Additionally, two open holes were cast into the floor during construction for bath and shower plumbing. The floor adjacent to the holes (14″ square) had to be lifted without the lifting material blowing out from under the slab.

Some of the owner’s belongings were to stay in the structure during the work, so the repair had to be clean and be able to address localized areas of floor which could not be directly treated (closet floors), floor under the bathtub, and floor under the kitchen cabinets.


High density polyurethane foam jacking for this foundation repair project. Foam jacking was completed in conjunction with chemical grouting, which was used to address the uncontrolled fill below the floor. Void sizes ranged from zero to two inches below the floor, with settlement up to two inches. Settlement and void presence were not correlated.


Concrete Jack foam jacking crew installed high density polyurethane to raise the settled portion of the slab back into place. The polyurethane foam jacking was completed in one day, and treated a total of approximately 900 square feet of slab floor.