In the central New Mexico mountains where we build, clay and other problem soils can behave unpredictably, expanding and contracting excessively, or settling and shifting. Add in an ill-timed rain or snow storm during foundation prep work, and what appeared to be a suitable, compactable subsoil can suddenly become a wet, sticky, non-compactable mess. Unfortunately, it's sometimes difficult to determine exactly what soil types exist below the footing trenches. Even proper soil investigations may not identify all problem areas, because the results are typically based on only a few borings that are taken to be representative of the site. Lean Fill When excavations reveal surprise soils with questionable loadbearing ability, we use a technique that protects against foundation settlement. Simply put, it involves
