The results are in, and Maricopa Meadows stands as the only subdivision in the community with sulfate levels high enough to cause moderate damage, according to the International Building Code.
The city of Maricopa commissioned AMEC Earth and Environmental Inc., a private firm specializing in soil studies, to take samples in 10 Maricopa locations, five in Maricopa Meadows, a sample in Alterra, Rancho El Dorado, Tortosa, Glennwilde and the last in an empty field on the southeastern corner of State Route 347 and Bowlin Road.
The homes tested in Maricopa Meadows had sulfate levels of .12, .17, .33, .34 and .03. None of the homes tested outside the Meadows had levels above .05, and one home in Rancho El Dorado had no sulfate in the soil.
The International Building Code defines sulfate levels between 0 and .1 as having a negligible effect on concrete; .1 to .2 as having moderate effects; .2 to 2 as having severe, and anything in excess of 2 being very severe.
“The levels of sulfates can vary drastically from home to home and from area to area,” said AMEC spokesman Brad Christensen. While the sulfates in the soil were not high in any community but the Meadows, the company also tested damaged areas on the foundations of homes for sulfate levels, finding sulfate levels between 2.26 to 7.79 in the one Alterra sample and a Maricopa Meadows sample.
“It is not clear if this is just a soil issue or if something else is in play,” he added. Christensen said his firm was contacted to do an independent study, free from the influence of the developers and homeowners tangled in a lawsuit. The claim, which is being pressed by almost 600 of the 1,600 homeowners in the Meadows, alleges the builders were negligent in their building practices because they did not use proper concrete mixes to ensure protection from sulfate attacks.
The basic science behind an attack is, when the soil becomes moist, sulfates dissolve in the water and are then absorbed by the concrete. As the sun dries the moisture from the concrete, the sulfates are left behind to break down the cement holding the materials together.
Regardless of the amount of sulfates in the soil, there needs to be a cycle of moisture and drying, Christensen said.
Christensen said he recommends people in the area look at installing rain gutters, grading the ground away from the foundation, utilize sealants to keep moisture out of the concrete slab and make sure sprinklers or drip systems are not causing moisture near the base of the home. “There should not be short-term concern in these communities,” he said. To determine long-term effects, he added, additional testing would have to be completed.
“If you are concerned about this problem on your property, we encourage you to do your own additional research as it pertains to your specific home, and determine what potential remedies are available to you,” said city spokeswoman LaTricia Woods.
Below is a copy of the report submitted to the city.
Photo by Jim Williams