Green Design Systems improves on bales, wins California clean-tech award
HEALDSBURG – Harry Hagaman set out to build a straw-bale home to alleviate his health problems, but in the process he developed a construction system bereft of bales and won a recent competition for green technology innovation.
Mr. Hagaman’s straw panel concept won the green-building category of the 2008 competition by Palo Alto-based California Clean Tech Open. The award includes $50,000 in cash plus as much in donated business services.
However, Mr. Hagaman estimates his venture, Green Design Systems, will need $1 million to $1.5 million to start producing the patent-pending panels.
The 56-year-old computer programmer turned artist turned entrepreneur has combined construction with factory-made panels, which can reduce job-site waste, time and labor, with straw bales, which can have insulation advantages.
“I have chemical sensitivities, so I needed to build a structure that was nontoxic to live and heal in,” Mr. Hagaman said. “I got interested in straw-bale construction, but I found it more difficult to build with.”
Used for centuries in homes and buildings in Europe and Asia as well as a number of North Coast structures, straw has been gaining in use in recent years amid the green-building movement as well as tougher rules on burning agricultural waste.
Central Valley farmers can only burn a quarter of the straw left over from harvest, and rice straw is problematic for plowing under to decompose, so there’s a ready supply for building a house out of straw.
Compressed straw can have an insulating factor up to R-2.96 per inch of thickness, compared with R-3.5 an inch for conventional blown-glass insulation. However, the physical density of packed straw versus blown glass allows the material to absorb and release heat, a property called “thermal mass,” evening out temperature swings in a building from day to night, according to the California Straw Construction Association.
Mr. Hagaman’s panels differ from common bale construction. Instead of stacking bales in place, wrapping them in mesh and adding framing for structural integrity, the panels have compressed straw wrapped in recycled-metal mesh and framed with Forest Stewardship Council-certified lumber.
He has a prototype of a panel-production machine and used it to turn out 4-foot-wide-by-8-foot-high panels and custom-sized panels for two demonstration projects. Panel weight varies with thickness and can range from 70 pounds for a 3-foot-wide panel to 150 pounds for a 4-foot-wide panel.
It cost a few hundred thousand dollars to develop the apparatus, and it can produce enough panels for four or five standard-sized homes per eight-hour shift.
According to the straw-building association, walls made from bales have a two-hour fire rating when they are plastered and 30 minutes without because the tightly packed straw doesn’t allow fire to “breathe.” Green Designed Systems’ panels are assumed to have the same fire rating, but official testing is still needed to confirm that.
And like other straw construction, these straw panels will need to be safeguarded not only after construction but also upon delivery to the job site.
Mr. Hagaman said a benefit of panelized straw is stucco or plaster can be applied on a horizontal surface, rather than a vertical surface, as with bale construction. Attachments can be inserted into the panel to hold interior wallboard and exterior siding.