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Mark discovered that thousands of homes built between 1980-2017 in Western Massachusetts and Northern Connecticut have concrete foundations with pyrrhotite in the aggregate. These foundations will, after a period of 20 years or so, begin to crumble until they are no longer structurally sound.
For more information, check the Connecticut Coalition Against Crumbling Basements.
Additional assistance with this segment was provided by Michelle Loglisci, Russ Dupere, and Mark Violette.
As Tom Silva explained during the investigation, the problem comes down to the aggregate in the concrete mix: “In the aggregate, in this particular concrete, we found a mineral called pyrrhotite. And in that pyrrhotite is another mineral called iron sulfide. So once that stuff gets hit by water or moisture interacts with it, it kind of puffs up, swells a bit and also rusts.” What seemed like a one-off issue turned out to be a bad mix that continued for decades.
The scale of the crisis is staggering—and financially devastating for homeowners. As discussed on the show, the value of affected homes has plummeted, and homeowners may not even be able to secure a bank loan against their properties. With an estimated 36,000 homes potentially affected, the problem can extend across entire streets and neighborhoods, drawing comparisons to other building-industry nightmares like urea formaldehyde insulation and lead paint.
