They are attractive houses, with flagstone paths and two-story entryways, lined up on quiet cul-de-sacs just three minutes from the freeway in Mission Viejo, Calif. They are comfortable homes, 2,000-2200 square feet each, with current asking prices approaching $900,000.

All seems fine to an ordinary passerby. “California Dreaming,” one might think.

But about six years ago, their owners were warned that these houses were full of defects and could be crumbling under their feet. That was the genesis of the lawsuit, Castron v. Fieldstone Pacific, in which the concrete producer defendant, National Ready Mixed Concrete, stood its ground, went to trial, won, and even got a judgment against the homeowners to pay for defense costs.

Although the appeal will likely last well into summer 2007, there are already indications this case has changed the climate of sulfate attack claims. There are also considerable doubts about the future, because new laws and changed building codes may alter the ground rules completely.

The trial concerned external sulfate attack, which has been at the center of millions of dollars in litigation the past 12 years. Sulfates dissolved in groundwater are alleged to seep into concrete foundations and slabs and react with chemicals in the concrete. They form microscopic crystals, which break down the structure of the concrete.

For sulfate attack to occur, there must be sulfates in the soil, they have to get into the concrete, and the concrete must contain the chemicals that react with them. When the phenomenon was discovered more than 50 years ago, special types of cement were developed, Type II and Type V, which resist sulfate attack because they contain less of the chemicals that react with the sulfates.

Code changes

For decades, Southern California residential projects built on soils containing sulfates were specified for 2000-pound concrete using Type V cement. In 1985, the Uniform Building Code regarding sulfates was changed. A sulfate resistance table was added, which called not only for sulfate-resistant cement, but also a lower water/cement ratio: 0.5 for moderate sulfates, 0.45 for severe sulfates. That translates to about 4500-pound concrete. Theoretically, this denser concrete would be less permeable to groundwater and the sulfates dissolved in it.

The legal problems arose because the code changed, but the practice in Southern California did not. “Engineers kept specifying 2000-pound concrete even when they found severe levels of sulfate in the soils,” says William Ingalsbe of Monteleone and McCrory, the lead attorney who defended National Ready Mixed Concrete. “They would specify Type V cement, which, in practicality, had worked for the past 30 years.

“Some engineers believe the code was never intended to apply to residential concrete,” explains Ingalsbe. “Residential concrete falls within the definition of ‘plain concrete' under the code, different from reinforced or structural concrete. Arguably, the requirement for sulfate resistance applies to all concrete, but engineers never interpreted it that way. No building official ever interpreted the code to apply to residential construction or required them to use 4500-pound concrete.”

Concrete producers were caught in the middle. “The engineer designs the concrete. He is the guy licensed by the state of California to do so, not the ready-mix supplier,” says Ingalsbe. “Developers kept issuing specifications designed by their engineers, and ready-mix suppliers kept supplying orders with 2000-pound concrete.”