Article No: 190

2006-07-27 09:56:25
NCMA Residential Award of Excellence
By: David Holzel



Photography courtesy of the National Concrete Masonry Association

  It lies low on the hillside, like a gunslinger in an old Western—flat on his belly peering over the scrubby ridge down to Tucson. Surrounded by the looming column-and-arms of the saguaro cactus of Old West iconography, you half expect to stumble across a bleached cattle skull.

Instead, there is the structure that the designers wanted—in its design and execution—to appear to grow out of the steep hillside without disturbing the fragile landscape. Concrete block, prominent inside and out, was a large part of achieving that aim—a material that supported the structure on its hillside perch and tied the home aesthetically to the rough country outside.

“Masonry was the only choice for this project,” say the architects, Luis Ibarra and Teresa Rosano of Ibarra Rosano Design Architects. “We used masonry inside and out to blur the distinction between desert and house, while mitigating sun exposure and focusing the views.”

Both Rosano and Ibarra are Tucson natives. They pride themselves on their deep understanding of the extreme conditions in the Arizona desert, an understanding they put to work on the home that won the NCMA’s Residential Award of Excellence.

Contest juror Patrick Rand called the 2,150-square-foot Garcia Residence “beautiful,” and lauded its “crisp geometry.” For the home, completed in 2001, designers Ibarra and Rosano created “three terracing platforms” that stepped up a hillside dotted with jojoba bushes, palo verde and saguaro. These platforms, or bays, divided the house into three zones: “living” on the lowest level, “circulating” on the central level, and “sleeping” on the upper level.

“We used the middle bay, the entry ‘gallery,’ for both circulation and as an extension of the living spaces,” explain the designers. “It invites the visitor down to the living, dining and kitchen spaces on the [north-facing] lowest platform, while connecting the house to the bedrooms on the [south-facing] upper level.”

The living space pivots so the main window can capture a view of Tucson and the Catalina Mountains. On the upper platform, the bedrooms are separated by a courtyard, which allows exposure to the southern sun and provides a view up the ridge.

“We wanted to do the least damage to the site as possible,” says Rosano, principal architect for Ibarra Rosano. Therefore, the terraces are narrow to keep excavation and fill to a minimum—14 feet, 6 inches on the living level; 8 feet on the circulation level; and 14 feet on the sleeping level.

Relying on standard gray CMUs as the primary building material helped the builders preserve the delicate environment around the home site, adds Rosano. The blocks’ modularity allowed easy delivery by crane to the locations where the material was needed. “The house was built from the inside, so there didn’t need to be an outside swatch of land that had to be used for staging,” she says.

The concrete block walls were reinforced by anchoring them directly into the bedrock, just below the surface. “That hillside is largely solid rock,” says Rosano. “We did that rather than pull the rock out and replace it with concrete.”

Once the walls were up, they were sandblasted, revealing the black and gray aggregates in the block.
The load-bearing walls were constructed using a post tension system in which steel rods span the distance between the stem and the top of the wall. Cavities in the block were filled with foam, providing insulation to the house. The CMUs’ thermal mass is a plus for energy efficiency in a desert environment.

“There’s a 40-degree swing from day to night here. The thermal mass helps moderate the swing in temperatures,” Rosano says.

With gray stone spread across the steep terrain, “the use of natural gray block was not only economical, but visually correct in the landscape,” the designers say. “While the gray color complements the gray-green jojoba bush, rusted steel echoes the veins of iron oxide coloring found in the fieldstone.”

As the project was underway, the number of the home’s residents increased. The client started out as a single man, Rosano says. “Partway through construction, his girlfriend—now wife—came into the picture. She loved the house.”

One effect she had on the design was to get the swimming pool, eliminated for budgetary reasons, restored. It was built at the east end of the house.

Although the home uses standard gray CMU primarily, the design includes other types of block that served specific purposes, and added subtle variations to the minimalist design. “Different blocks with different uses have a different aggregate mix,” Rosano explains. “So the 8-inch corner blocks are a different mix from the blocks that are used around the lintels. So it does add to the interest.”

Juror Rand took note of this aspect, writing, “The cool massiveness of the concrete masonry walls is in contrast to the open and warm-hued materials finishing the spaces.”

The secondary building materials—steel, birch and concrete—share with concrete masonry the simple and durable qualities that complement the desert environment. And while the home site is not quite as lonesome as it seems—there are neighbors nearby, Rosano says—the Garcia Residence’s 3 acres are surrounded on two sides by protected land.

And on the hillside, the home lies low—almost a piece of the desert itself.

Article and photography reprinted with permission from the National Concrete Masonry Association.