Chemical Injection or Soil Injection Foundation Repair are when non-toxic, water-soluble chemicals (potassium ions and ammonium salts) are injected into the ground under your building. These chemicals inhibit soil’s ability to absorb water so that when it rains your soils do not swell up.
WHEN IS IT USED?
Water sticks to almost anything including clay. This attraction causes clay soil to swell. The trick is to use a non-swelling chemical to stick to the clay before water does. When an appropriate concentration of the right chemicals is injected into clay, the chemicals stick to the clay molecules and prevent the clays from absorbing water. Once in place, the chemicals stay attached to the clays. In a way by injecting the chemicals into the soil and “coating” the clay, you create a moisture barrier, stopping water from causing more foundation upheaval.
HOW DO WE DO IT?
In most cases, for existing structures, chemical injection is done around the perimeter of a foundation. If there are driveways, patios, decks, or other paved surfaces, ¾ inch diameter holes are drilled through the paving to reach the underlying soils. The chemical solution is injected to depths ranging from 7 to 10 feet. The solution is injected at relatively low pressures, typically on two separate days. The solution is pumped from a truck to a manually operated injection wand.
Injections can be done on the interiors of buildings, however, interior treatment requires that holes be drilled though the floor every 2 feet (one hole for every 4 square feet). While exterior injections are hardly noticeable, this is not true for interior injections. When interior injections are being done, the contents of a home must be removed because the chemicals do stain and can splatter during injection.
IS IT TOXIC?
The materials used in the solution are not toxic in small quantities. In the ground, in dilute concentrations, they actually act as fertilizers. The materials should not be ingested. If the solution gets on a person’s skin, simply wash it off with soap and water.
HOW DO I PREVENT UPHEAVAL OR FIX UPHEAVAL?
Foundation maintenance can prevent some types of upheaval through the installation of proper foundation drainage including:
- French drains
- Moisture barriers/root barriers
If foundation upheaval has already occurred, the following types of foundation repairs are recommended:
- Foundation lowering
- Foundation underpinning
According to the soil report for one of our projects, the soil should be injecting to prevent it from absorbing water. Chemical injection is done around the perimeter of the foundations in rows of three layers. The solution is injected to depth of 4m.