Tranquil and temperate, Mill Valley, California is a small, idyllic town roughly 15 miles north of San Francisco. Despite being characteristically quiet and relatively obscure, it is a city marked by a handful of defining qualities. Enjoying access to a variety of natural touchstones like the Muir Woods and Edgewood Botanic Garden, Mill Valley has historically been a magnet for creative types to retreat to for undisturbed artistic focus (from Van Morrison to Jerry Garcia and George Lucas). It should come as no surprise then that such creative energy would be expended in service of the city’s natural environment when an award winning environmental writer and an environmental artist decided to use fledgling bamboo paneling company BamCore to transform their pacific residence from the ground up.
The owners of the Mill Valley property, BamCore CEO Hal Hinkle says, wanted to construct a replacement home that was “much more thermally efficient” and “super green” in terms of the materials used. These are noble goals, and ones that would be familiar to BamCore founder William McDonald, whose frustration with the inefficient thermal bridging of traditional stud walls and passion for material renewability led him to devise the paradigm-shifting innovation now known as BamCore. In these terms, BamCore is the most revolutionary product on the market in the most literal sense of the word. It subverts the established, and woefully outdated, model of wood framing by introducing a new foundational resource—bamboo—and liberates building framing from the need for its securing and inherently flawed core of studs.
“In order to solve the thermal bridge problem, you can’t have any studs in the wall,” Hinkle instructs. But since studs serve the fundamental purpose of framing a conventional wall and supporting the roof and floors above, spotty thermal performance has long been a sacrifice most contractors and architects have accepted as the price of framing the wall. After all, what good is a great thermal performance if you can’t hold up the roof? What BamCore has discovered is that by supplanting wood studs and exterior OSB sheathing with structural bamboo panels in a robustly efficient, hollow dual-panel system, you can both achieve all the structural requirements of the wall while also substantially improving the thermal performance. This opens up the insulation decision to any type of blown-in material.
Eliminating studs from the structural equation elevates the energy efficiency performance of a building spectacularly, most notably by reducing the aforementioned thermal bridging. The dual panel hollow-wall system tightens the building envelope of the home, thereby reducing air infiltration and maximizing insulation. Diminished airflow invasiveness translates to diminished energy consumption, which culminates in splendid cost savings for the residents. And sealing the thermal bridge has the ancillary effect of likewise shuttering the acoustic bridging, a feature admired by Daniel Weaver of 361 Architecture and Design Collaborative, who was the principal architect on the Mills Valley residence. Weaver recalls the follies of earlier California-based developers. “When they started building lofts and converting warehouses in San Francisco, they would insulate them with old wood timbers,” he recollects, “so when they went to sell them they realized the sound was transferring through the floor beams and the roof beams. It was a huge selling issue for those projects.” The market had decided that sonic constraint is a safeguard of human comfort.
The bamboo alternative has enormous potential to combat “clearcutting,” the scorched earth process of logging that entails deforesting a wealth of trees in a given area. This is in part due to the rapid pace at which timber bamboo grows in contrast to most strains of wood. “When you cut down trees you’re cutting down something that took a minimum of 15 to 25 years or more to grow,” Hinkle says, while timber bamboo grows about five times faster than all construction wood timber. Not to mention, when you cut down a tree, stump form is a life sentence, whereas bamboo can regenerate to full height and be re-harvested annually. Bamboo also has the environmental advantage of mitigating the greenhouse effect. “While growing in its plantation,” Hinkle explains, “bamboo sequesters more carbon dioxide per square area per acre than a typical wood forest does.” Therefore, by switching from wood to bamboo, the industry could dramatically curtail the amount of CO2 that enters the lower atmosphere and is causing the climate to change.
What perhaps makes BamCore most ripe for an industry-wide paradigm shift is the simplicity with which they equip you to facilitate it. Rather than building on-site, BamCore takes the architectural CAD drawings of a building design, cuts the wall panels prefab from the factory, and delivers them to the site with foolproof instructions that enable the contractor to assemble the panels in the order they’re numbered. “It’s paint-by-numbers,” Hinkle explains. “The builder no longer needs to offload all kinds of studs,” he illustrates, “having to cut them all to their length and then figure out how to rough frame all the windows and doors.” It’s a process Weaver implies could potentially have democratizing effects on the profession. “The way BamCore is assembled is relatively simple,” Weaver affirms. “With very little training you could build a 20 foot wall of BamCore relatively quickly.” As general rule, when approaching a task, most people gravitate toward modes of labor that reduce their mental and physical strain. By rendering the greenest mode of production the most undemanding, BamCore stands to make sustainability a no-brainer.
Weaver’s job was to help the owners build an environmentally-sensitive house on a challenging hillside lot. This drove a strong contemporary design, which included a butterfly roof that catches rainwater. Builder David Hill of Spellbound Construction, had the job of building the contemporary style home with a highly sustainable but radically new way of framing walls. “Despite challenges due to the design and BamCore’s new way of framing,” Hill explained, “I would gladly do it all over again. I truly believe that BamCore is at the forefront of a new way of smarter building.”
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