Another thing Tom the Contractor suggested for reversing the loss of moisture under my slab foundation after the root barriers were installed was to rehydrate the soil. That’s a fancy word for squirting water into the dirt under the house.
One of his crew went all around the foundation with machine similar to a power washer with a plunger attachment. A garden hose was attached and the plunger was pushed a good three feet deep into the soil every 24 inches or so. A valve on the handle controlled the flow of water.
Between the rehydration treatment and a better soaker hose configuration we are getting moisture back into that clay soil.
UPDATE: This was probably not needed given the slab leak that was discovered a few years later.