Stormwater Drains

Settlement of sidewalks or formation of sinkholes around stormwater drains is a very frequent problem.  The diagrams below outline the steps that result in uneven concrete and sinkholes around these structures.


During construction, a large amount of backfill material is placed around the drain structure, usually with inadequate compaction.


As the backfill material settles, voids form under the surrounding concrete, or if there's no concrete, the grass settles below its original grade.  Slight shifts in the structure are pretty common, and cracks and openings in shifted joints form.

Surface water flows into the voids, and washes soil through cracks and openings in joints into the interior of the drain structure.  Soil is often evident inside the structure by looking through the water inlet or manhole cover.  Surrounding concrete starts to settle, resulting in often-significant trip hazards.


Concrete Jack's crews fill the voids under concrete or any sinkholes on the surface with a special high-flow grout mix.  The grout mix is injected into the void areas at high pressure, helping to ensure complete filling of the soil fisures and lock the existing soil in place.  Any settled concrete is lifted back into place and the surface is restored to original condition.