Why hire a Geotechnical Engineer? To avoid problems such as the ones presented in the photographs below.
Every new construction project should have a geotechnical engineering evaluation. Here are some thoughts for those considering ignoring a formal subsurface characterization study (geotechnical evaluation):
(1) It is a part of the normal "standard of care" to determine soil conditions before designing and constructing a foundation or pavement system.
(2) The Texas Section of the American Society of Civil Engineers (ASCE) "Recommended Practice for the Design of Residential Foundations" requires that "prior to foundation design, a geotechnical investigation and report shall be completed by a Geotechnical Engineer."
(3) The International Building Code (IBC) Section 1803 requires a soil investigation be performed for the design of new foundation elements except where waived by the "building official" if satisfactory subsurface information from adjacent areas is available. Be careful on how you define "satisfactory". The IBC also states "in areas likely to have expansive soil, the building official shall require soil tests to determine where such soils do exist." Many areas in Central Texas are likely to have expansive clay soil, therefore a geotechnical study is be default required.
(4) Structural home warranty companies such as 2-10 HBW require a geotechnical evaluation for every house lot. If a Builder does not have a geotechnical evaluation performed, they set themselves up for a conflict with the warranty company with regards to whom might have to pay for repairs.
(5) The post-tensioning institute (PTI) requires as stated in their Design of Post-Tensioned Slabs-on-Ground manual that "a single lot investigated in isolation should generally include 2 borings [...] a minimum of 20 feet in depth [...]"
(6) Pavement section thickness design is provided by a knowledgeable Geotechnical Engineer. Without a geotechnical report, your pavement may not be designed to be reliably durable for the soil conditions at the site.
(7) The Association of Pool and Spa Professionals recommends site specific structural and geotechnical engineering for in-ground concrete or gunite swimming pools.
Engineers are responsible to the public and to the Texas Board of Professional Engineers. For examples of enforcement punishment related to engineers who have skimped on geotechnical evaluations or have made mistakes related to inspections or design, visit:
If you are an Owner, Developer, Contractor, Subcontractor, or Architect, please realize the permanent burden of responsibility put on engineers before considering their work "too conservative" or as we prefer to say "safe". "Safe" and "engineering" are supposed to be synonymous. The alternative is just plain reckless. Unfortunately, with limited budgets, engineers already work at the margin of safe and risky.