RASTRA® turns "take-out" trash into Earth-friendly building blocks.

Story from "Teton Home" Magazine.
Written by: Tom Walsh

Ari Kotler wanted a home that was more than just energy efficient. He wanted to build it from materials that put no strain on the Earth's ecosystem and would help consume some of man's immense amount of waste material. Take a peek at the packaging leftovers from any McDonald's meal, and you will see what he means.

Although only 26, Kotler, originally from the Boston area, has been a whitewater rafting guide in the west for almost 10 years. He has built his adult life around the serenity of the wilderness; he guided for six years in Northern California on the Tuolumne, Kern and Salmon rivers, and spent several years in Northern Idaho on Hell's Canyon of the Snake River. When he came across Teton Valley about three years ago, he realized he wanted to drop anchor here.

Kotler holds a lifetime lease on 20 acres tucked back in the forest on Teton Valley's West Side, part of a larger property owned by a family corporation. He began researching alternative construction materials several years ago. His mind was open, but he remained dedicated to building with environmentally favorable materials.

He finally selected RASTRA®, a building system originally developed 30 years ago in Austria that pairs concrete with recycled polystyrene (known to most people by the brand name Styrofoam); Kotler came across the product while doing research on the Internet. Many areas in Europe have suffered from tree depletion for a long time, and Europeans are well ahead of most Americans in using alternative building materials, he notes.

RASTRA® is manufactured from waste polystyrene, a material certainly plentiful in modern society. With a life span of more than two million years, non-recycled polystyrene could surly be one of the modern scourges of the Earth.

The lightweight building blocks, when filled with concrete, create extremely strong, well-insulated walls. Specifically, RASTRA® provides a 10 inch thick wall rated at an R-25 insulation level, as compared to the R-19 rating of a standard frame-built and fiber glass insulated wall, according to information found on the company's web site, WWW.RASTRA.COM The thermal mass of the concrete provides the insulation advantage.

RASTRA® is extremely energy-efficient, as well as fire- and frost resistant. It also provides built-in soundproofing. And because of the materials near perfect vapor diffusion, there is almost no opportunity for condensation or mold to form, the site explains.

With arches and curves available pre-made from the factory, construction can progress considerably faster than when using conventional building techniques. Transportation costs are minimized by the lightness of the material, and there is little waste material to clutter up a building site. Dan Young a contractor from Ketchum and regional representative for Earth Friendly Building Materials, an Arizona-based company that distributes RASTRA® in several western states, supervised the initial "pour" of Kotler's home. This involves filling the airspace in the RASTRA® blocks with concrete after first inserting rebar for structural support. Proper bracing of the RASTRA® walls, doorways, and window area is of cardinal importance when the actual pour occurs, Young says. The initial pour formed the exterior walls for the lower, walkout level of the Kotler structure. After talking and working with Young, Teton Valley builder Kelly Lee handled subsequent pours.

Young has completed about eight projects in the Sun Valley area, including both residential and commercial structures. Dan Chouinard, owner of Earth Friendly Building Materials, feel strongly about having field reps, like Young, who have front-line experience with the product. Earth Friendly Building Materials is headquartered in Tempe, Arizona, while the closest RASTRA® manufacturing plant is in Juarez, Mexico. The facility is located near the sony plant, which of course provides an ample supply of polystyrene packing, the main ingredient of RASTRA®.

Although RASTRA® is heavily used in the Southwest, it is a relatively new concept in Idaho. According to Young, fewer RASTRA® building permits are issued in this state than in the Phoenix area alone. But it is making inroads, particularly in one of Idaho's most progressive towns. "Alternative building materials have become a very important concept in the Sun Valley area. Everybody can see firsthand what's happening with the forests, and they all seem to be looking for a more healthy, environmentally sensible approach to building materials," Young says.

RASTRA® is not the only alternative building material available; a similar product called I.C.E. Block consists of solid blocks of recycled polystyrene. But Kotler chose RASTRA® because it offers 10 times the resistance impact of I.C.E. Block, he explains. In addition, because of RASTRA's porosity, plaster can be applied directly to its surface, with no need for the expense or additional labor requirement of using chicken wire.

Kotler also notes that RASTRA® is manufactured almost entirely from recycled materials, in a process that is gentle on the Earth. Finding practical ways to reuse the Earth's refuse is never far from Kotler's mind.

The strength of a RASTRA® home comes from the rebar-reinforced concrete in the wall channels. The channels are unique that they extend both vertically and horizontally, which increases the strength of the material while allowing builders to use the blocks in either vertical or horizontal applications.

Wall blocks are stacked by hand and glued together. Held together prior to the exterior wall pours with adhesive and temporary clamps, the walls may be rasped clean of excess adhesive once the concrete has set.

Walls can be pre-assembled at the factory with the window and door openings pre-molded, further reducing on site construction time and costs. Once the walls are erected, grooves are cut to accommodate plumbing and wiring.

Driggs architectural designer Rene' Lusser worked with Kotler on the initial design. The octagonal home will be finished to resemble an adobe abode, with a beehive fashion fireplace, as Kotler has grown to admire the Southwestern style in the six years his sister has lived in the Santa Fe, New Mexico area. Plans call for a 3,000 square foot, three-story structure with a ceramic studio in the basement but only two bedrooms, a possible result of Kotler's bachelor lifestyle. He is quick to point out, however, that the design provides great flexibility and potential for future additions.

An immense spruce tree trunk harvested as standing dead timber in Colorado anchors the house, both visually and physically. This center post boasts a circumference of more than eight feet at the base, rising 19 feet through both floors of the house to the ceiling of the second floor, where it still has a 6-foot circumference. The ceilings are backboned with massive glue-laminate beams, which come together in a steel compression ring at the apex of the roof.

The compression ring was forged by Travis Rockefeller of Steel Tech and design in Driggs. "It's the key to holding the entire roof and house together'" Kotler says. " There are massive pressures brought together at this point, and it's the job of the compression ring to properly distribute them."

With a split-level entrance, the house contains Kotler's ceramic studio, a bedroom and a bathroom on the bottom floor. A sunken living room and dining room on the second floor look east to the Tetons while the kitchen faces west toward the Big Hole Range. Finally the top floor houses the master bedroom, closet and bath.

Kotler derives considerable satisfaction from researching various environmentally sensitive building materials and then selecting those that best fit his application. For example, he chose another recycled material for his roof. "It's called Flexshake and is made from the treads of old steel radial tires," he explains. "The stuff is treated to be non-flammable and carries a 50 year warranty, with a life expectancy of 100 years." Flexshake comes in numerous colors and closely resembles traditional shingles at a fraction of the cost and weight, according to Kotler. Flexshake is actually coated with quarried slate and is considered hail proof.

For the outside decking, which will be considerable to maximize the home's beautiful vistas, Kotler has selected a material called trex, a composite manufactured from old plastic egg cartons. The non-slip material requires no staining and is impervious to rot.

"You know, just about everybody recycles now, but they don't really get it," Kotler says. "That's only half the picture. Until people complete the circle, and begin to actively use recycled materials in their daily lives, the Earth will continue to be ravaged by the pressures of the throwaway culture."