Crumbling-Failed Foundations

Crumbling Foundations or Failed Foundations

Identified as Crumbling Foundations or Failed Foundations

Cause: There are several reasons why concrete fails to bond together. One of them that has been identified in Northeastern Region of Ct. is related to a mineral found in the aggregate called “Pyrrhotite”. Pyrrhotite can cause concrete used for foundations, Septic Tanks, Precast concrete products such as hatchways, stairs etc. to fail by breaking down. The initial signs are what is called “mapping cracks”. Initially mapping cracks are small and hard to see and then eventually grow to be very large and cause shifting and movement to the product.

Inspection and testing: There are 3 ways to evaluate a concrete foundation for Pyrrhotite as follows:

  1. Visual inspection. This is limited and is hard to pick up small cracking in the initial stages
  2. Solution spray. This is applied to the foundation and highlights cracks that cannot be seen with the naked eye. This will help when looking to see if the foundation has started to react to the pyrrhotite and is in the initial stages.
  3. Core samples, also known as core taps. This is when we cut a approx. 4” round opening in the foundation in 2 or 3 locations and take the concrete out for lab analysis. The hole is then filled properly to prevent leaking and the samples are labeled and sent to the lab. Once the lab evaluates the content they provide a report that provides the amount of “Pyrrhotite” in the core samples. This process has been recommended from the state of Ct. to get on the list for assistance.

Each of these methods can be good for the intended purpose if the person inspecting and evaluating the foundations has the knowledge to properly know what to look for.

Sherwood Inspections Services, LLC has inspected hundreds of foundations for Pyrrhotite in the past 3 years. If you have any questions about your foundation give us a call and we will get one of our engineers or inspectors to assist you.