Straw bale construction:
try huffing and puffing these houses down

It's no fairy tale. Although straw bale homes conjure up images of the fabled first little pig's straw house, no amount of huffing and puffing - or strong winds, for that matter - can blow these homes down.

by Lorin Hallinan

f Jim Danielson has his way, more homes in San Diego County will be built using a resource that never seems to run out. Danielson, who has been in the construction business for 10 years, would like to build homes using bales of straw. They're far from flimsy. Once covered with stucco or similar material, straw bale is extremely fire resistant, Danielson pointed out. Examples of his sturdy work using straw-bale construction have been featured at environmentally-conscious events such as Earth Day in Balboa Park.

The way Danielson sees it, straw-bale construction is a responsible gesture toward Mother Nature, and one that makes sense. Instead of seeing the dry grain stems burned or buried or simply wasted, Danielson believes the byproduct can be put to good use. Since cereal grains are grown in most states, there would be plenty of straw to go around. "Straw bale is an annual renewable resource, unlike timber that can take 30 or more years to come back," he noted. "There's an awful lot of people I've talked to who have heard about straw bale. It's just a matter of time before we can get the building department to cooperate."

Through his business Epic Living, Danielson has submitted three proposals to build straw bale homes in the county, including 38 acres in Fallbrook and several thousand acres on an Indian reservation.

If Danielson's proposals go through and investment money comes in, Jim Bell will come on board as the ecology consultant. Bell, an ecological designer at the Ecological Life Systems Institute in San Diego, is considered a leading authority and expert in his field.

Bell works with individuals and businesses to help them improve methods of doing things that make sense economically and ecologically. He supports the belief that straw-bale construction makes sense. "Straw is a naturally occurring material, and if used properly in a structure, it's very durable and also an excellent insulator," said Bell. "If a house is built and serves its purpose for 100 years, the major materials, meaning straw, could break down and go back into nature. That's what we need to look toward. In long terms, it's a cradle-to-cradle resource movement."

Old and new

The compressed rectangular bales of straw used in building usually come in two versions, either two-tie or three-tie bales. Tied with plastic string or wire, the smaller version measures 18 inches wide, 14 inches high and 36 to 42 inches long and weighs about 55 pounds. The three-tie version weighs about 80 pounds and measures 23 inches wide, 16 inches high and 42 to 48 inches long.

As novel as the construction method sounds, it's not new. Straw-bale construction dates back to the last century. Homesteaders in Nebraska started using straw bale to build homes in the late 1800s, out of necessity. With timber in short supply, people turned to the renewable resource they had on hand - straw from wheat, barley and rye harvests.

Unfortunately, Nebraska-style straw bale homes are illegal to build in many states, including California and New Mexico. Not enough tests have been done to convince building department authorities of their stability.

With the Nebraska method compressed bales of straw serve as the main support for the roof. Using this load-bearing technique, a continuous beam is placed around the house's upper wall on top of stacked straw bales, and then a roof is put on top of that. (Think of them as big bricks.) The technique does not comply with the Uniform Building Code, which dictates the way homes can be built in many Western states.

The thumbs-down reception given to Nebraska-style straw-bale construction isn't holding Danielson back. He's adjusting to the obstacle by promoting a rendition of the Nebraska home, one that uses straw bales as insulative infill rather than support. Wooden post and beam framework would bear the load of heavy roofs, which satisfies building code requirements. Concrete slabs would keep the straw dry and off the ground, and chicken wire around the straw would provide a surface for stucco to be applied. Stucco sealants, ample roof overhangs and well-maintained exterior wall surfaces keep out moisture and humidity out.

As far as insects are concerned, straw bale is usually not on the menu. For one thing, straw has virtually no nutrients and common house eaters, like termites, devour wood not straw.

New Mexico bales out

New Mexico is one state leading the way in new construction of straw-bale homes. The only state that controls building at the state level rather than the county level, New Mexico is in the process of incorporating an amendment to its building code to allow for more homes to be constructed using straw bale.

According to Tony Perry, who owns Straw Bale Construction Management Inc. in Santa Fe, New Mexico, once the amendment goes through, people in other states will most likely pay attention to it and ask for engineering data and other information. "Obviously, they'll have to make up their own minds," said Perry, an Englishman who's enthusiasm for straw bale homes led him to found his consultancy company that serves to help architects and builders. He has lived in Santa Fe since 1990 and serves as chairman of the New Mexico Technical Advisory Committee and as president of the national Straw-Bale Construction Association.

Perry, like Danielson, has been so swayed by straw bale's potential, he's convinced many people in the area to jump on the bandwagon. Perry has spent more than a year lobbying the New Mexico state government to permit experimental housing. At the end of 1993, New Mexico officials agreed to allow 10 experimental permits. They soon expanded the number to 20, and this summer decided to allow an unlimited number of experimental permits.

Perry said about 80 owner/builder homes are occupied or in the planning stages right now. The homes range in size from 600 square feet to 8,000 square feet, with several falling into the 3,000-square-foot category. "It's clear to me that it's going to grow and grow and grow," said Perry.

Big cost savings

Under contract with the federal government, the Technical Advisory Committee, which advises New Mexico's building bureaucracy, recently conducted a feasibility study about straw bale. With the help of the New Mexico School of Architecture, design work has been completed and two prototype homes will be built to feature straw-bale homes as alternative, affordable housing. "If you design them properly and subcontract out different bits, even have family and friends help build the house, we believe you can cut the cost by 40 percent to 50 percent," said Perry.

The homes, which have an adobe look to them, are very attractive, Perry pointed out, because the walls are thick and solid, typically 22 inches thick. They're so thermally efficient, he added, that utility bills plummet.

Perry recently was involved in a test conducted for the federal government that compared utility bills from conventional wooden homes with bills from straw-bale homes. The straw-bale houses saved as much as 75 percent on utilities.

They're cheaper to build, too. Danielson, who plans to build two straw-bale homes for his own use on land he owns in the Mt. Shasta area, estimates they cost about $10 a square foot to build, compared to $80 to $100 for conventional homes in San Diego County.

The homes may well be the best thing that ever happened in terms of affordability, but are they safe? According to Perry, prototypes fared remarkably well in fire rating, wind load and insulation tests performed by independent professionals.

Safe and sane

During a two-hour fire test, for instance, a section of a wall constructed with straw bale was placed against a furnace. Within five minutes, the temperature shot up to 1,000 degrees Fahrenheit, then 1,750 degrees after 60 minutes. "Wood catches fire at 500 degrees," noted Perry. "If the wall had been wood, it would have burned. If it had been steel, it would have buckled."

To pass the test, the temperature of the wall on its cool side could not exceed 250 degrees or have any flames penetrate it. After one hour, the temperature on the cool side had actually dropped two degrees, according to Perry, because a fan had been blowing. As the temperature on the hot side topped out at 1,940 degrees, the cool side temperature rose only 12.7 degrees! Remember, it could heat up to 250 degrees before failing the test.

For the wind test, the equivalent of a 75 mph gale was directed at the wall. To pass the test, the wall could not move more than 3/8 inch. "We had no movement at all," said Perry. "We took it up to 100 mph and it moved only 1/16 inch."

To prove straw bale's superb insulation benefits, testers examined the material's "R" factor, a numbered rating system used to determine how well a material insulates. Higher numbers indicate relatively better insulation.

A six-inch wooden wall with fiberglass insulation, for example, carries an R factor of 19. The average roof rates R30. One bale of straw without any plastering rated R48. "That's why utility bills go down," said Perry. "We've taken a very thorough, professional approach to this and had all the tests done by outside professionals. Everything was done according to acceptable standards, which is why the state has moved forward."

Danielson hopes San Diego can follow suit, as well as the rest of the country. "I want to be doing this across the United States," said Danielson, who currently pursues the straw-bale part of his business part-time. "I want to change from timber homes to alternative building styles. I want to decentralize energy sources so people can use their own electricity and water. It makes a whole lot of sense. My motivation is preserving our natural resources and making people responsible and self-sufficient. What we're doing now doesn't make sense."