I'd like to share a case study from a recent job that I consulted on with one of our contractor customers, ETRU Spray Foam and Coatings and Coatings in Southern Illinois.
A 25’ x 40’ residential pole barn in Carbondale, Illinois was built on a 6” floating concrete slab on grade. The concrete was poured into four 10’x 25’ sections. Each section had multiple cracks and breaks throughout, and in some cases, the broken sections had a drop of up to 3”. During the inspection, it was discovered that the pole barn 4 corner beams were driven into the ground and the concrete poured around them. The front of the property was pitched towards the pole barn and it showed no signs of ever having gutters and downspouts attached. After drilling an injection hole, we inserted a probe to check the depth of the void and the stability of the ground. In some areas the void was 6” and the probe was hand driven to a depth of 3’ before hitting hard ground. ETRU Spray Foam and Coatings was hired to stabilize the ground and level as much of the concrete as they could. The homeowner plans to utilize the space as a game room.
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The ETru crew and I walked the project with both property owners. We pointed out how waterlogged the ground was and that they needed to add gutters and downspouts, as well as pitch the ground water away from the pole barn. We also talked about possible blowout from under the slab during the injection process and how to handle it. I worked with ETRU to draw up a plan, indicating exactly where the injection points would be located (knowing that the plan might change due to the ground moisture and the number of voids to be filled). All injections were completed from inside the pole barn with a crew member on the outside to alert us when product broke through the ground. First, we injected in the back corner which had the 3” drop. The plan was to establish a base slab height on the side with the most soil problems and then level everything else to that slab. Spacing between injection points was approximately 3-4 feet, with 38 total injection locations.
The ETRU Spray Foam and Coatings crew achieved a three-inch lift and was able to bring all the other slabs within 1/8” from the adjoining slab. The customer was extremely happy with the results.