Is water ruining Tucson's historic adobe?

Story from the archives by Jad Davenport / Feb. 13, 2004

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Historic adobe houses in Tucson, Ariz.(Anne Weeks)

Back in the 1970s, while thwarting the city's efforts to carve a freeway through Tucson's Barrio Libre neighborhood, native son Kelley Rollings discovered an affinity for adobe.

He says he liked the sense of history reflected in the Spanish-Mexican architecture, the Sonoran soul kneaded in houses of clay, sand and straw. Behind the sun-dried brick facades, Anglos, Mexicans, Chinese, Spaniards, and Indians mixed easily. Barrio Libre, Rollings says, has more adobe buildings than any neighborhood in North America.

It was this legacy that resonated in Rollings. "I figured the easiest way to make sure no one bulldozed these buildings was to own them," he says. During the next three decades, he purchased and restored more than 28 abode houses, some of which date to the 1850s. It was an expensive endeavor—renovations can cost $175 per square foot—but one Rollings thought might be a wise real-estate investment. Every building is now on the National Register of Historic Places.

Then something strange happened. Buildings that had held up in the desert for almost two centuries, buildings the Rollings family had restored from roof to floor, began to crack and slump.

Adobe is one of the oldest building materials; when properly made and maintained, it can last for centuries. But for all its simplicity and strength, it has a fatal flaw. If exposed to continuous saturation, its binder material—usually straw or grass mixed in to help the adobe bricks dry uniformly—dissolves. As the bricks dry out again, they crack and disintegrate.

Water has damaged this adobe building, owned by the Rollings family. (Anne Weeks)

Rollings' son Donald is responsible for the ongoing maintenance and restoration of the family's properties. "We had plaster popping off the facade," he says. "Inside, plaster on the walls fell off and electrical wiring was completely rusted through." When he couldn't find leaks in the plumbing—there were no adjacent pipes at all—he checked the roof and again came up empty-handed. In a region that gets less than 13 inches of rain annually, Donald was baffled.

The first lead came in the winter of 1998-99, when the city began tearing out and replacing water lines in the Barrio Libre district as part of a project begun in 1981. Out of the 3,500 miles of iron and galvanized pipes serving 600,000 people in the greater Tucson area, the city discovered more than 220 miles of deteriorating mains that needed to be replaced.

"The pipes were leaking, soaking the earth around the buildings," Donald Rollings maintains. Unlike modern houses, in which foundations isolate the entire structure from the surrounding soil, adobe walls are constructed right on the bare ground. "What happened was a natural capillary process, where the adobe was sucking up water from the wet soil," he says. "I went out to a water meter box one day. It was 104 degrees and hadn't rained in six months, and that box was saturated." Fire hydrants, his father says, were some of the worst offenders.

So the family filed a claim with the city for $3 million, alleging damages caused by leaking water mains. It was denied.

Kelley Rollings in front of one of the adobe buildings he restored (Anne Weeks)

Instead of replacing all the suspect pipes, the city chose a less costly alternative of cleaning some and lining them with cement. Discouraged by what he considered to be half measures, Kelley Rollings finally decided to file a lawsuit against the city in 1999.

Rollings hired soil expert Ralph Pattison of Pattison Evanoff Engineering to collect and analyze samples taken near the damaged buildings. According to Pattison's 1999 report, the moisture content of a typical soil sample is less than five percent. "Moisture contents higher than 10 percent are extremely rare and almost always indicate some nearby source of water," Pattison wrote. When moisture content reaches 13 percent, adobe aficionados will tell you, the binder dissolves. The lowest moisture content in the soil taken from the Rollings' properties measured 12 percent; many were as high as 16 percent; and a number had moisture contents greater than 20 percent. Rollings says water has damaged about half of his 28 adobe properties.

The city attorney's office refused to allow Preservation Online to interview Tucson Water engineers. In Phoenix, 120 miles northwest, K.N. Jagannath, a civil engineer with the city water department, spoke about similar issues there: "Our pipes were put in 70 to 80 years ago, and they have a normal lifespan of about 50 years." The most common problem, Jagannath says, is corrosion. "The pipes get clogged, and the diameter gets smaller and smaller until the water pressure bursts them," he says. Phoenix rarely tries to rehabilitate the fractured lines because "it's far more effective to dig them out and replace them," Jagannath says.

Tucson officials maintain they have either replaced or repaired leaking pipes in Barrio Libre. Chris Avery of the city attorney's office says the city surveyed the areas using leak detectors and is satisfied that the water distribution in the soil meets generally accepted engineering levels. "I'm not saying there's not a leak," Avery says. "But the issue revolves around proof. In this case, the issues of proof are very difficult. It's tough to know what exactly is going on underground." If the suit can be settled in arbitration, Avery says, it might be settled in a few months. If it goes to trial, it could last years.

A Barrio Libre adobe (Anne Weeks)

While his son continues to patch new cracks and fissures, Kelley Rollings is busy packing up his office at the America West Gallery in the Barrio Libre. The floors here have buckled, and the electrical lines are rusting. This is his favorite building—the oldest he has restored—and Rollings reminisces about the thick walls surrounding him.

"This place was built as a ranch residence back in the 1850s, when we were still a part of Mexico," he says. "There are adobe buildings in Africa and the Middle East that are over 1,500 years old, and they are still standing. There is no limit to how long they can last."

Rollings pauses, then adds, "Unless, of course, they happen to sit next to a leaking fire hydrant."

This article originally appeared on Preservation Online on Oct. 25, 2002.

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