Utilization of Existing Infrastructure
The building site lies near the village of Busby. No new drives/roads were added to access the home on a rural unpaved road. The house is walking distance from village services. It is also near the major road, facilitating vehicle access and reducing site impacts due to transportation.

Preservation and Protection of Sensitive Areas
The building itself is located near the site of a demolished building in an area previously cleared for earlier construction. The home is adjacent to the home of extended family members.

Consolidation of Utilities
This location, given its proximity to existing buildings and community infrastructure, also permitted short utility runs, reducing the cost and disturbance of acquiring utilities.

Preservation of Trees and Existing Vegetation
No trees or shrubs were removed from this site for construction. The site was re-established using Native Plants that will facilitate education and require no watering once established.

Minimal Impact on Site Topography
A frost-protected shallow foundation was chosen as a less invasive design since it does not require excavation for footings below the frost line. This foundation is discussed in more detail in the following sections. Slight modifications to the site grading were made around the perimeter of the foundation allowing water to drain away from the building while irrigating the adjacent community gardens.

Orientation for Use of Renewable Energy
The building is oriented to take advantage of passive solar gain. Solar gain in the concrete slab, facilitated by south-facing windows, complements the radiant floor heating. For more information on the radiant floor system see the Energy Efficiency section.

Orientation and design for daylighting
The minimal use of interior partition walls allows daylight to move throughout the entire space. The primary fade presents south-facing windows for passive solar gain in winter.

Window Sizing, Location and Shading
Windows are located on all four sides of the building. Most are operable including two of the southern clerestory windows to allow cross-ventilation of the space. A roof overhang on the south side, designed using solar angle data, shades windows in the hot summer months but permits sun throughout the winter. Given the long Montana winters, introducing and storing solar energy while insulating the interior takes precedence over summer shading.

Foundation
A frost-protected, shallow foundation was constructed to provide an energy-efficient, low-impact base for the building. This type of foundation minimizes excavation and material use. Rigid foam was installed around the slab to insulate it as required by local conditions. Learn more by visiting the National Association of Home Builders resources and NAHB Research Center Toolbase Services. Climatic data for design of frost-protected shallow foundations is now provided on a website developed in partnership by National Climatic Data Center, National Associate of Home Builders Research Center, and American Society of Civil Engineers.

Structural Framing
The building envelope is built out of stacked wheat straw bales - an agricultural byproduct. Above the approximately 8 foot high bale wall, panels from James Hardie form the upper exterior envelope.

Materials made from agricultural byproducts or recycled content were used for their inherent structural, insulating or aesthetic value. More detail on this system is available here.

Windows
All windows used are double-glazed.

Exterior Wall Finishes
The exterior walls were finished in stucco applied by hand by the volunteer work force.

Finish Floor
The high-volume @fly ash concrete@ slab foundation doubles as the building's finish floor. Fly-ash is a byproduct of coal fired electric generating plants and an inexpensive and suitable substitute for portland cement. A non-toxic stain was used to give the slab its color.

Other
The interior of the strawbale walls were finished in stucco. All interior partition walls are sheathed in gypsum board.

Insulation is integrated with the structure in most of the exterior envelope. In the few areas where additional insulation was needed, gaps were filled with either loose straw or blown-in Cellulose insulation made out of recycled newspaper.

Products with Minimal Off-Gas
A Low VOC elastomeric paint was used to finish the interior stucco walls. Interior trim was finished with linseed oil. The concrete floor stain was a non-toxic, bio-stain called OS Color.

Reduction of Textiles, Maximized Hard Floor Surfaces
Colored concrete is the finished floor surface throughout this building. This surface is easy to clean and will eliminate moisture buildup.

Bathroom and Kitchen Fans and Dryer Vented to Outside; Tested
Exhaust fans installed in baths and kitchen vent directly to the outside.

Ventilation Design (related to climate conditions)
Natural ventilation is the primary method of air circulation in this building, operable window are supplemented by several exhaust fans. The majority of the windows are operable allowing for cross-ventilation and thermosiphon-driven airflow.

Building Envelope
This building was constructed with a frost-protected shallow foundation. The foundation is insulated reducing the need to excavate below the frost-line. It also provides an energy efficient base.

The walls were then built using Straw Bale Construction and a fiberglass insulated roof plane (described above). Straw bales are made from a locally-produced agricultural by-product. Bales provide superior insulation increasing energy efficiency. All windows are double-glazed.

Mechanical Systems
A radiant floor heating system in the slab is augmented by passive solar gain. The slab acts as thermal mass storing heat from the sun throughout the day. The radiant flooring system is joined with the domestic hot water system. A thermostat, relay and pump circulate water through PEX tubing in the slab. An evaporative cooler chills and circulates air on peak cooling days.

Water Heating
A hot water boiler provides hot water as well as heated water for the radiant hydronic flooring system.

Lighting
daylighting strategies are used in most of the interior spaces. All light fixtures are suggested to be fitted with compact fluorescent bulbs.

Best Management Practices (BMPs) for Stormwater
A swale was constructed about the homesite to direct stormwater away from the foundation. The swale will subsequently be planted with native Montana plants.

Rainwater collection and reuse
Water directed away from the foundation is redirected towards the adjacent plantings.

Water Efficient Appliances, Equipment and Fixtures
Low-flow fixtures for the toilets and sinks were installed.

Landscape Design
Landscaping around the building designed exclusively with native plants.

Access to community support services
Due to its location within walking distance from the village of Busby, Montana what services are available are easily accessible.

Exterior access
A ramp leading to one entry provides access for wheelchairs or those with limited mobility. Sheltered exterior spaces were provided so that occupants could choose to work or convene outdoors during good weather.

General living space
Flowing interior spaces are an asset in an area with such extreme weather conditions. The house showcases a number of technologies which could be adopted in other local homes, and provides a visitable example for other homeowners to learn from.

The building is fully accessible with all spaces visitable by those in wheelchairs. Additionally, the interior space is relatively barrier-free, and all spaces were designed with a five-foot turning radius. These features provide space for wheelchairs to maneuver, as well as comfortable access for the elderly or disabled.

Other
The ERC project was designed with active participation together with the homeowners themselves through a participatory design process. Family and cultural factors weighed in on many factors of the home design.