In addition to the legacy report, the following guidelines are to be applied:

  1. Expansive soil or loose soil behind a proposed wall will have to be carefully investigated before installing block wall.
  2. If there is a potential for a high water table, a perforated drain pipe is used to divert water behind the wall at the base.
  3. A concrete swale above the wall is required on slopes to drain surface water away.
  4. Tree roots behind the wall need to be removed or not allowed to expand close behind the wall.
  5. Base courses set up mid-slope can be installed with additional recommendations for a stable wall.
  6. A retaining wall less than 27 degrees and a minimum tilt of 10 degrees will require a soils report and structural calculations by a registered engineer.
  7. Open-spaced block assembly with a 6″ crushed rock backfill behind the wall will not have a problem with gophers or other rodents yet still allow plants to grow inside pockets created between blocks.