Greg Esparza pushes the ecological envelope with Cross Cabin in Austin

Material Manifesto

Greg Esparza pushes the ecological envelope with Cross Cabin in Austin

The exterior of Cross Cabin is clad in cork panels, an insulating product that is typically concealed under another facade. (Casey Woods)

Designed by Moontower founding co-partner Greg Esparza for his young family, Cross Cabin in Austin prioritizes plant-based products, from its cork-clad, cross-laminated timber enclosure and interior walls to the use of laminated paper as a hard surface material for showers and countertops. The direct result of an early-career designer exploring what an environmentally aware practice might look like, the building serves as a material manifesto, architectural prototype, business experiment, and livable showroom for process and product all at once.

The project pushes hard on the environmental paradigm that architectural value can arise from how a building should neutrally impact and, ideally, enrich the natural ecosystems at all phases of its life: construction, use, and disassembly. Could it even improve the well-being of the people involved in the process?

exterior of Cross Cabin house
The materials chosen for Cross Cabin are nontoxic. (Casey Woods)

While Moontower focuses on renewable materials, it was equally critical at Cross Cabin that the materials chosen are nontoxic. This commitment to wellness extended beyond manufacturer transparency regarding chemicals and labor practices: Moontower was also intent on creating a nontoxic environment on the job site. Commonplace hazards like spray foam insulation and fiber cement, drywall, concrete, latex paint, and polyurethane were eliminated.

Concern for job site health arose within a larger reconception of residential assembly. As Esparza put it: “The usual layer cake of materials and trades in a typical home wall assembly is something I was reacting to. So, rather than latex paint over fiber cement over a weather-resistant barrier over sheathing over insulation over framing, enclosed with drywall that was painted—all of which required painters, framers, insulators, and drywallers—I designed the house as just cork over a weather-resistant barrier over CLT, all of which can be assembled by carpenters.”

wood kitchen and wood interior balcony level
A double-height gathering space unites the home, and more private second-floor spaces are lofted around the perimeter. (Casey Woods)

Like many students entering architecture school in the early 2000s, Esparza, when he enrolled at the University of Texas at Austin School of Architecture where I taught him, was confronted with the seeming irreconcilability of two powerful concerns in architectural discourse: intellectual respect for critical architectural form on the one hand and the pressing ethical consideration of environmental performance over formal sophistication on the other. As at many schools, these interests were then associated with identifiable camps of faculty that barely overlapped.

Interior spaces are defined by CLT panels for floors, walls, and ceilings, offering a pleasantly continuous material palette. (Casey Woods)

Compelled to excel in both areas of investigation, Esparza cofounded Moontower in 2010 with Frank Farkash and Jeff Munoz. They envisioned a collaborative design/build practice focused on resolving nagging conflicts between environmental response and affordability, humanistic spatial organization and construction geometry, and architectural oversight and craftsperson skill—which meant they were often the folks building the buildings.

Esparza hoped for a house commission that would allow him to maximize the use of plant-based materials. But Cross Cabin Build and Supply, the Moontower satellite company that Esparza runs, grew out of a dawning awareness that there are few clients (don’t let Austin’s reputation fool you) willing to commit to radical paradigm shifts. Esparza realized the only way to make it happen was as an active agent rather than passive recipient. The Cross Cabin house is the first of several prototypical houses Moontower has designed. It’s a relatively unconventional model for architectural practice, lacking a clear track for economic success. As Esparza was constructing the house, he realized that many of the products and systems were being used in Austin for the first time. By the end of construction, Cross Cabin had become the local rep for Amorim Cork Insulation, mafi natural wood floors, Alkemis Paint, TimberHP wood fiber insulation, HempWool insulation, VaproShield, and Simpson Strong-Tie. That’s the “supply” part of Cross Cabin Build and Supply.

cork walls
Cork also appears in the interior, as seen in the bathroom. (Casey Woods)

Business model aside, the house is also a rigorous investigation into mass timber panels. By setting various panel proportions perpendicular to each other, and thereby generating short cantilevers, and by accounting for the use of all cut pieces, Esparza has been able to generate remarkably rich layering, especially in the making of surprisingly deep, glass-enclosed window seats and startling sectional slots of space. Yet the house is directly and straightforwardly detailed, allowing the basic steps in its fairly simple carpentry to remain evident.

wood walls in the bedroom
In the bedroom, plywood surfaces are naturally lit via a skylight. (Casey Woods)

Esparza argues that “a more tangible engagement with the act of making houses is a step in the right direction when it comes to material health and indirectly embodied carbon considerations.” He calls his home a cabin because, despite its spatial sophistication, the image of the cabin evokes “a counterpoint to the tendency in the modern prefab world to focus on portraying their product as the next point in a technological march of progress.” Moontower is building from the ground up, sidestepping the virtue-signaling of green building or envirotech—and moving toward a more grounded, tangible practice.

David Heymann is an architect, writer, and the Harwell Hamilton Harris Regents Professor in the School of Architecture at UT Austin.