CT Foundation Issues10/3/2016
GlobeSpec has been talking to William Neal is who a professional engineer in Connecticut and has been involved in approximately 200 cases of foundation failures in the NE portion of the state where this problem is prevalent.
Recently we have learned of a potentially significant structural problem that is associated with homes in Connecticut. Based on information from the state of Connecticut Department of Consumer Affairs structural failures of more than 300 homes foundations in the Northeast portion of the state have been reported over the past few years. After extensive research by the state it has been determined that the cause of these foundation failures is due to the presence of pyrrhotite in the concrete aggregate that was produced by Joseph J Mottes Company and Becker Construction Company from 1982—2015. Naturally, the presence of most minerals in rock confers some degree of strength in structures. However, this s not the case with pyrite. Research has shown that concentrations of pyrite as low as 1 to 2% have an adverse effect on the structural integrity of a foundation, under certain conditions. Building foundations that contain pyrite tend to stain to a brownish color since the pyrite oxidizes. Also pyrite reacts with oxygen so readily, it tends to weaken the structure of the concrete, resulting in increased incidences of foundation failures.
From our discussions with a structural engineer and from published information from the state of Connecticut here is additional information on this subject;
It is estimated that this issue is effecting about 25% of the homes in the state
30 mile radius of Stafford CT is the target area
Timeframe is estimated to be homes built from 1982 until December 2015
Cracks can appear at any time and in some cases structural problems have been reported 15 – 25 years after foundation was poured.
Foundations are not repairable, but some contractors are misguiding owners with repairs that will not correct the problem
Replacing a foundation is the only option, but will cost 150K-300
The State of Connecticut has also issues an Advisory directed at Home Inspector. Please see attachment
Based on this information we must be sure to exercise extreme caution when inspecting any home in Connecticut, regardless of age or location. From the inspection standpoint any home that exhibits any cracking, deflection, sloping floors, bowed foundation or displacement must be considered a potential structural concern, regardless of the magnitude of the condition. In all cases where any structural concerns are raised by the inspector we will be calling for a further evaluation by a professional engineer. Additional information on this subject can be found at www.ct.gov/DCP/concrete
There has a been considerable research regarding possibility of testing foundations to determine if pyrrhotite may be present. In our further discussions with a professional engineer on this subject we have learned that there are several companies offering testing services of foundations for $400-$600. Unfortunately these companies are not licensed, insured or trained and the test is not valid for pyrrhotite. Other tests, using core samples of the foundation cost $5,000-$6,000. Core sample only test approximately 0.0007% of the concrete used in an average sized foundation and cannot reliably predict a future problem with such a small sample of one area.
Additional information can be found through a local news article and video about the issue (7min long):