23Nov 2016

Dealing with Soil Subsidence can be Quick and Non Disruptive

By Robert Armstead

Dealing with Soil Subsidence can be Quick and Non Disruptive

Services---Undersealing-and-Voidfill-ImageOn November 18th, the Tampa Bay Times published a story entitled Is one of Tampa Bay’s premier condo towers sinking?.  The article discusses how “very loose and very soft bay bottom soils” have caused movement of the foundation that has resulted in “significant subsidence concerns and structural design deficiencies.”

Soil Subsidence is a common problem in Florida.  Florida’s sandy soils and geological conditions can cause the soils to collapse away from the surface often times leaving voids underneath foundations and surface structures.  Under instances where there is overbearing weight, the support soils will become inadequate to support the structure. 

First of all, it is always best to ensure that the soil compaction density is sufficient before building the structure.  However, when the case of natural erosion or soil subsidence occurs there are repair methods that have been tested and used in Florida for many years, a process which was referred to in the article called “soil stabilization.” A soil stabilization method that is commonly accepted is the use of an engineered proven polyurethane chemical grout.

The main issues to address when repairing soil subsidence are to restore or increase the soil’s weight-bearing capacity and to fill any voids.  Soil stabilization using an expansive polyurethane grout accomplishes both of these goals.

When injected, polyurethane saturates the soil layer and then it begins to compact the surrounding soils as it expands.  If injected in the right pattern, the soil can be stabilized, the weight-bearing capacity restored or increased, and the voids under the structure will be filled.  The best part of the process is it is fast and causes minimal impact to the existing slab.

Soil subsidence can cause severe problems to a building’s operations and its structural integrity. The good news is there are repair options to rehabilitate those soils that causes little impact to the property and can be completed fast and effectively.

Kathleen Shanahan is Chairman of Ground Works Solutions, Inc., a Lakeland, FL based company.