Straw-bale houses have come a long way since Midwestern homesteaders used to stack sod on the Great Plains and call it home. More recently, 20th century straw-bale builders were either crunchy, granola types hand-crafting their own über-green homes, or affluent greenies seeking to create off-grid trophy houses, budgets be damned. In all cases, though, straw-bale has been the preserve of the one-off – designed and built one at a time. Until now.
One Boulder architect is adapting a European production model that has allowed him to increase his straw-bale business exponentially and factory-produce homes less expensively than other high-efficiency, architect-designed housing. Brian Fuentes stacks framing and bales on conventional slab foundations, runs wiring and plumbing throughout and covers the bales with imported hydraulic French plaster that hardens like concrete. The result – a pre-fab panelized system – is artisanal, high-end yet it still has the warmth of the human hand.
The key to Fuentes’ economies of scale is in the framing process, and where that happens – in a production facility versus on site.
Fuentes, a 35-year-old architect in Boulder, models the houses in his studio, builds the load-bearing framing there, stuffs the framing cavities with straw bales and applies two coats of plaster. He transports the dried panels to the job site, and PRESTO! -- Installers erect the completed walls sealed full of straw. Fuentes compares them to LEGOS, and he says he aims to “take the drama out of straw-bale building” with his process.
Straw-bale houses conjure images of the “three little pigs” – straw houses collapsing under the big, bad wolf’s heavy breathing. Yet the fable belies reality.
The houses are twice as insulated as code-built homes (R-40 wall systems versus R-21), and they withstand fire better than stick-frame construction. In fact, a Fuentes home withstood one of Boulder’s notorious canyon fires this summer. Fuentes attributes the house’s surviving because of its metal roof and lime plastering.
The holy grail for high-efficiency building is carbon neutrality, and that’s where straw-bale outpaces almost everything. Most of the building materials he sources are local – straw from Alamosa, Colo., clay from Golden and lumber reclaimed from Boulder. And “net-zero” housing (where energy use in equals energy generated and saved) is easily within reach with straw-bale building.
Fuentes is a visionary who speaks rapid-fire about his vision for the building industry, peppered with high-efficiency building stats. He grows misty when he talks about the “orders of magnitude” that straw-bale homes can save in energy – 10 times less needed for heating and cooling compared to conventional homes, and 75 percent less total energy, with lighting and appliances.
Boulder is the perfect place for Fuentes, who studied architecture at the University of Oregon, another hotbed for green building. Building straw-bale there was fun, he says. “You had big, thick walls inside, and it feels cozy. It works well in earthquake zones because they’re kind of sponge-y. The bales bounce around.”
Boulder building codes require all newly built homes to be 25 percent more energy-efficient than conventional homes so straw-bale is one option for homeowners. Before he began pre-fabbing straw panels, he said he worked on four homes a year. Because of his factory system, he’s already been involved with 13 projects this year, including his own home, which he’s building from the ground up.
While Fuentes may be simplifying what’s essentially an artisanal process, he’s hardly in danger of upending the home-building industry.
Though early in his career, Fuentes has been involved with only 25 of the homes. In 2010, national single-family housing starts numbered 470,900, and that’s 80 percent off the building peak of 1.7 million in 2005, says the National Association of Home Builders. Even in Boulder, Fuentes plays for a small team, and he estimates he’s one of only five straw-bale builders there, one of 25 in Colorado and only one in maybe 100 nationally.
His homes can’t compete with conventional stick-built homes, selling for $80 to $90 per square foot. Fuentes’ costs are double, and his straw-bale homes ring in at around $200 per square foot. But it’s still well below what he says other architects of super-efficient construction charge ($300 per square foot) because of expensive materials like foam-insulated panels.
Even with stratospheric energy efficiency, Fuentes says straw-bale isn’t for everyone, describing many of his clients as willing (and able) to make a “legacy investment” in their home. Straw-bale wall panels can be as thick as 18 inches, and Fuentes says that the self-absorbed who’ve bought into “bigger is better” don’t choose straw bale.
Though he’s tried to make the process drama-free, it’s not always that way, recalling one client whose wife, they discovered, was allergic to straw. Once the walls were sealed, though, he said the problem was solved.
While Fuentes’ production process may not be a home-building game changer, the energy savings that straw bale affords cannot be ignored. “This makes zero-energy affordable,” he says. “And today’s renewable technology at today’s prices possible.”