Permanent Soil Nail Walls – Calabasas - CA “Blending In” Original Site As increasing demand for housing pushes developments of the flat lands and into the surrounding hillside the need for economical retaining wall systems increases. Once great solution is the use of permanent spoil nail walls that can be sculpted and stained to match existing surrounding and provide a relatively aesthetically pleasing appearance to future homeowners. Permanent Soil Nail Wall in construction