Helio Terra - CODAworx

Helio Terra

Submitted by Robert Horner

Client: City of Moscow, Idaho

Location: Moscow, ID, United States

Completion date: 2012

Artwork budget: $30,000

Project Team


Robert Horner

Pi R Squared

Rammed Earth Builder

Bly Windstorm

Earthdwell ltd


Helio-Terra is a rammed earth construct that depicts the solar rhythm specific to Moscow, Idaho. The installation is situated on the Southern edge of the Wren Welcome Garden located at the intersection of State Highways 8 and 95. The Installation falls along the axis of the park and serves as a visual anchor and gateway into the Town of Moscow. Helio-Terra is a mass of locally quarried earth that is compacted into a form resembling a seed. The geometry of artwork is gesture towards the agricultural heritage of Moscow, as well as the grain towers that flank the site. The seed is a concentration of nutrient that gives forth the energy necessary to yield future sustenance, and thus serves as a metaphor for the community of Moscow. Helio-Terra strikes a direct connection between the sun and the harvest. The installation highlights the furthest reaches of the sun along the horizon and depicts solar-rhythmic seasonal crests that have served as anchors for farmers for thousands of years.


Helio-Terra is an original and unique design for the City of Moscow created by Robert M Horner. The project was constructed in partnership with Bly Windstorm of Earthdwell LTD, a licensed Rammed Earth builder. Constructed from stabilized rammed earth, Helio-Terra easily reached compressive strengths to that of concrete, yet utilized a fraction of the embodied energy. The form is compiled in thin 5 inch lifts of an earth mix containing varying degrees of iron-oxide. The varying color lifts of earth result in a dramatic and dynamic effect that mirrors that of the rolling hills of the Palouse. Similar to the landscape of the region, the artwork becomes a canvas for shifting light and color as the sun traverses the sky. The artwork has concave cavities varying in degree of aperture that correspond to solar orientation. These apertures shift between shadow and radiance with shifting light as they map the suns path across the sky throughout the year. The project was complete on a very tight project budget with minimal impact to the existing Wren welcome garden park.


Rammed Earth is a well graded mixture of subsoils with an appropriate amount of silt and clay and a small amount of Portland cement to provide the necessary strength to meet engineering requirements as well as to provide protection from the elements. Naturally occurring iron oxides are added to the mix to provide a range of colors. The resulting walls are beautiful and completely non toxic. The walls are fully reinforced with steel rebar and are engineered to withstand the tremendous forces that accompany an earthquake.

The Rammed Earth forms for the installation were 5-axis cnc-milled and constructed in Port Townsend, WA. The rammed earth was sealed to prevent staining and ensure an extended life. The artwork will stand for hundreds of years with minimal weathering reflecting the integrity of the agricultural community and the important relationship between the sun, earth and harvest.