Deep Foundation Stabilization and Crawl Space Environmental Remediation in Milan, IL
Challenge
The building's perimeter foundation experienced downward displacement caused by inadequate soil load-bearing capacity and seasonal moisture fluctuations within the active soil zone. Desiccated clay soils underwent volumetric contraction during dry periods, depriving the footing of continuous vertical support and initiating structural settlement. Concurrently, an unsealed, vented crawl space environment allowed capillary water migration through the earth floor and foundation walls. High ambient relative humidity, standing groundwater potential, and unmanaged soil gas emissions created conditions conducive to organic growth, sub-floor timber rot, and compromised indoor air quality through the stack effect.
Solution
To arrest settlement, transfer structural loads, and isolate the building envelope from ground moisture, the team executed a dual underpinning and encapsulation protocol.
First, for structural underpinning, the crew excavated targeted access pits and attached steel brackets beneath the footing. Hydraulic equipment drove high-strength steel helical piers through unstable surface soils until reaching target installation torque on dense load-bearing strata or bedrock. The load was locked off onto the brackets, permanently transferring the building's weight to stable soil and halting further settlement.
Second, for environmental remediation, the crew cleared and leveled the crawl space earth floor, installing dimpled drainage matting to create a continuous drainage plane. The team then installed a heavy-duty, multi-ply CleanSpace® vapor barrier over the matting and up the crawl space walls with mechanically sealed terminations, isolating the sub-structure from groundwater and humidity.
