Bill Adams groans aloud when he hears the story about the "Three Little Pigs."
Remember the tale? To escape the advances of an evil wolf, one pig decides to build a house of straw. But the wolf huffs and puffs and blows the house down. So the second pig tries sticks. But the wolf took bigger breaths and that house failed as well.At last, the third pig builds a brick house, which withstood the wolf's huffs and puffs. Although brick held up against the wolf's heavy breathing, seismic forces can reduce masonry to a jumbled pile of mortar and brick, says Adams, president of Great Habitat Homes of Salt Lake City.
A concrete foundation also can give way to seismic activity and literally crack into pieces, causing the structure to collapse or slip off its base.
Had Adams written the classic children's tale, he would have encouraged the pigs to with build their home from top to bottom with wood.
Adams, who has 22 years of building experience in Utah and serves on the board of directors of the National Association of Homebuilders, says permanent wood foundations may best protect a home from significant earthquake damage.
Wood, he explained, can "give" enough to allow the shock wave to move through the house without significant damage to foundation or structure.
In an earthquake, the forces of shaking ground are absorbed within a building. Since wood doesn't weigh as much as concrete or steel, it can withstand earthquake forces and curb its cumulative destructive force.
Permanent wood foundations are constructed of pressure-treated lumber cured at up to 60,000 psi and is treated to resist moisture and termites. "They (termites) will die if they eat the wood," Adams said. The designs utilize a concrete floor but the "walls" of the foundation are built of treated wood and backfilled with dirt.
The U.S. Forest Service has conducted accelerated tests that showed the wood could last more than 100 years without moisture or insect deterioration. The 100-year figure is comparable to the life of concrete foundations, which are more susceptible to damage from moisture and seismic activity.
Thus far, Great Habitat Homes has built six homes in Utah that have permanent wood foundations, including an all-wood house at 11277 S. Wyngate Lane (1985 East) to be featured in the August 1991 edition of Better Homes and Gardens. The design by Gregory Hackworth, an employee of Burnstead Construction of Bellevue, Wash., was judged winner of the 14th annual Innovations in Housing Design competition. The contest was sponsored by the magazine, the American Plywood Association and Builder and Progressive Architecture.
Contest rules required designers to adapt their designs to Utah's climate and cultural conditions.
The design utilized what builders call "Code Plus" construction. That distinction requires building walls, floor and roofs that exceed minimum building code requirements by using thicker panels, proper fastening and careful spacing of structural members and wall sheathing.
Additionally, plywood used for structural panels will flex and not break, which makes it an excellent choice for sheathing. This property also helps reduce seismic damage.
Engineers who studied the damage caused by the California earthquake of Oct. 17, 1989, noted that some plywood sheathed and sided buildings experienced minor damage. The engineers concluded that framed construction built to meet existing building codes performed well during the earthquake.
Another advantage is energy efficiency. The house has a warmth rating of R-19, compared with the R-2 of a concrete basement. The higher the R value, the greater its ability to hold heat in the space, Adams said.
Adams estimates about 100 homes in Utah have permanent wood foundations. So are they a novelty or a safety measure that will become a standard part of home construction in seismic risk areas?
Given the wide swings in Utah's weather conditions and threat of significant seismic activity, Adams says there ought to be more use of permanent wood foundations in new construction in Utah. Not only is the construction earthquake resilient, it also is energy efficient.
But most homebuyers consider their pocketbooks above energy savings or safety from the forces of Mother Nature.
"Frequently all that is taken into consideration is the monthly payment," he said.
But money spent upfront could translate into a long-term savings should a major earthquake rock the Salt Lake Valley.
The wooden foundations cost about 15 percent more than a traditional concrete foundation, but a savings would be realized if and when the "the big one" occurs."
Utahns have mastered the art of emergency preparedness in terms of establishing food storage and keeping on hand sleeping bags and cook stoves. Oddly, the same methodical people are reluctant to spend extra money to build an earthquake-proof home or incorporate an auxiliary power source or water reservoir in their home's design.
Is it worth the trouble? "Ask the people in California who went through it," Adams said.
Adams said he believes the use of permanent wood foundations will not become widespread in Utah until a major quake strikes the area.
"It takes a tragedy, unfortunately," he said.