Preservation of Trees and Existing Vegetation
Abundant trees on the site were left in place through conscientious design and practices. Trees that were removed for the driveway and housing site were milled locally and then used for interior framing and paneling.

Modest Size Design
This home is 1800 square feet with a long, narrow open design. The home was custom built using a preliminary design provided by the homeowner. The design was originally for a home in the southwest; it was modified for the climate and regional conditions of Tennessee.

Orientation for Use of Renewable Energy
The long-axis of this home faces due south for optimum passive solar advantage. The north and west side of the home are earth bermed providing for natural insulating properties.

Orientation and design for daylighting
The orientation and window placement take advantage of natural light in the home. Skylights add to daylighting potential in darker rooms.

Window Sizing, Location and Shading
The southern side of the home is constructed of glass and steel. High efficiency windows (see Green Products) were used to optimize solar intake and insulation. Overhangs of 18 inches were added to the design to help block summer heat gain and take advantage of winter solar gain. Insulating shades block against heat loss on the coolest days.

Foundation
An insulated slab was poured on footers extending below the frost line. The slab was surrounded with rigid insulation providing greater comfort to the occupants and increased thermal retention.

Structural Framing
Engineered truss span from the exterior walls on the southern side to the northern. Engineered lumber reduces impacts on large diameter stock since it provides structural integrity using smaller diameter trees.

Windows
Hurd doublepane windows were used to take advantage of passive solar intake and daylighting within the home. The windows have a Low-e coating but maintain a solar heat gain (or shading) coefficient of .55 to allow for ample passive solar intake for heating.

Exterior Wall Finishes
Two of the exterior walls are constructed of tires packed with earth and then bermed with additional earth for great thermal mass. The south wall is entirely glass. The remaining wall is finished in cement stucco.

Finish Floor
The insulated slab serves as flooring for this home. Grooves were cut in the slab to simulate tile and a rough finish was achieved between the grooves. A low-VOC paint was applied to the finished floor to add color. The paint finish has proven to have drawbacks and color will be added directly into the mix in future projects by this builder.

Cabinetry and Trim
Locally grown oak was used to build custom cabinets for the entire house. A durable concrete counter top was installed in the kitchen.

Other
A soil-based cement stucco was prepared on-site and applied to the walls for the interior finish. This material used soil from the site and cement at less than 20% to create a maintenance free finish.

The ceiling and trim were finished with 1x6 panels from the tulip poplars cut from the site. The trees were rough sawn on-site and then brought to a local mill for cutting and kiln drying.

Alternatives to Burying or Burning Construction Waste
Very little waste was generated on this construction site due to the use of natural materials. In fact, tires that may have been destined for landfills were reused as part of the building structure. Cardboard boxes, which arrived as packaging on many materials, were removed for recycling.

Products with Minimal Off-Gas
Careful selection eliminated products with the potential for off gassing. low-VOC paint was used to finish the concrete floor.

Water-Based Finishes
Cabinets and wood paneling were finished with Crystal Lac, a water-based lacquer.

Sealed Combustion or Power Vented Appliances
The propane stove and wood stove are vented directly to the outdoors.

Reduction of Textiles, Maximized Hard Floor Surfaces
A simulation-tile concrete floor is accented by throw rugs in high traffic areas. The rugs can be readily removed and cleaned reducing build-up of dirt and moisture in the home.

Ventilation Design (related to climate conditions)
The operable skylights help to provide natural ventilation throughout the home. Vents provide additional cooling during warm summer nights.

Water Management for Foundation, Attic and Walls
Water is a big issue to manage in this location. To prevent water collection the home was situated so that the grade slopes away from the foundation. Two below-grade French drains were installed beneath the berms surrounding the house. A swale was also constructed to direct water away from the berm.

Detached Garage (or attached with "advanced sealing")
The detached garage was constructed with a rubble trench foundation. The roof is topped with living soil and vegetation.

Harmful Gas Monitoring and Control
Combination smoke and CO2 detectors were installed in this home. A passive radon system consists of a corrugated, perforated loop buried beneath the foundation in a gravel bed connected to a vent that discharges above the roof.

Building Envelope
Two sides of this home are constructed with earthpacked tires with earth berms, which create a thermal mass "battery". Construction began with a cut in the hillside, which created a flat area and a slope that were covered with plastic. Rigid insulation was placed underneath the plastic for additional insulation. Several courses of tires were stacked up to eight feet high. Soil was added to each tire and compacted. Soil was also added behind and over the tire courses and tamped into place to form the earthberm. A layer of EPDM rubber, a synthetic rubber polymer made from ethylene and propylene monomers, was placed over the berm and tied into the roof for an added moisture barrier.

Fiberglass batt insulation was installed to give the roof an R-value of 70.

Mechanical Systems
This home is completely off the electric grid. It is powered by a hybrid Micro Hydro generator, distributed by Harris Hydroelectric, and 1.2 kW photovoltaic (solar) array. The energy is stored in batteries in DC then and inverter produces AC, which is used throughout the house. Outback Power and BP Solar supplied parts for the solar system.

A 500 gallon propane tank provides fuel for cooking, clothes drying and a backup system for hot water. A soapstone, high efficiency wood stove is the secondary heating system, the primary being passive solar.

Water Heating
The water is heated by means of another 3x7 solar panel. This solar water collector is a system of circulating propylene glycol, which preheats water prior to entering the Bosch instantaneous hot water heater.

Appliances
An Equator compact dishwasher and Staber horizontal-axis clothes washer conserve both water and electricity.

Lighting
Daylighting provides a significant portion of light in this home. Compact fluorescent bulbs provide the remaining light.

Best Management Practices (BMPs) for Stormwater
Stormwater is directed away from the home by way of a swale. Two settling ponds capture the runoff and sediment.

Greywater Collection and Reuse
"Greywater" from the sink, shower, dishwasher and washing machine drain into an on-site filtering and transport system. This system provides water for growing vegetables and reduces loads on the "blackwater" treatment system that handles waste from the toilet. More detail on this system is available here.

Rainwater collection and reuse
Rainwater is channeled into a cistern and used for irrigation purposes.

Wellhead Protection
Springs on the property are gravity fed into the home to provide domestic water. The home is situated on a 28-acre lot providing a buffer from potential neighboring contaminants.

Water Efficient Appliances, Equipment and Fixtures
The Staber clothes washer saves energy, water as well as detergent.

Landscape Design
A gravel driveway and flagstone pavers provide permeable surfaces for runoff. Landscaping in the areas that were impacted by construction consist of raised beds of compost and local rock. The vegetation is southwestern in origin and includes plants with low-water requirements.

Other
A "blackwater" waste treatment system was constructed to handle sewage on-site. Sewage from the toilet is channeled into a settling tank to remove solids. Nutrient rich water is then directed into a below-ground "pond". The pond was created by lining a hole with EPDM rubber, then a gravel bed, a 3-inch layer of sand, and finally 2 feet of soil. The wastewater is utilized by deep taproot plants, such as shrubs that thrive on the moisture and nutrients. Due to the abundant rainfall in this part of the country, a drainfield was added to handle overflow.

Exterior access
There are no steps to ascend when entering this home.

General living space
The open design and single level of this home supports easy accessibility. The doorways were constructed with a 3-foot swing, providing ample room for a wheelchair or walker.