Construction Details

Montana has published the Montana Residential Energy Code Handbook . Blacktail Solar Homes will be guided by this handbook and will meet these requirements, and in many cases exceed them.

Information common to all construction phases can be found at Temperature Control


Possibly the most important element in low input home design is the insulation. Insulation protects the investment in heating the space naturally by keeping the heat from escaping out of that heated space. Blacktail Solar Homes have R-50 in the space above the ceiling and R-20 or better in the walls. Crawl spaces under the houses are insulated to about R-15. All combined, these houses have excellent thermal characteristics.

Winter Heat

Solar heating is a big part of Blacktail Solar homes. You will find it described in some detail at Heater details.

Electric heating is usually not the least expensive, but these homes are designed to require relatively little heating, and the solar panels will offset much of the cost. All external heat is electric.


Phase II of Blacktail Solar Homes is framed with 2x6 studs. All of the space between the studs is filled to a depth of 3 inches with Sprayed Polyurethane Foam (SPF) insulation.

Comparing stud/SPF construction with the Phase I Structural Insulated Panel (SIP) construction gives some benefits and costs for each. SIPs have smaller vertical supports and thus transfer less heat to the outside from the inside. Stud/SPF is stronger and completely air tight so no heat is lost due to air flow. The insulation part of the R value will be acheiving R-20 or better with both systems.

The Blacktail Solar Homes insulation subcontractor has supplied a brochure describing in detail the product to be applied to Phase II, Rhino Linings ThermalGuard cc2. In that brochure the advantages are described as follows:

  • ICC-ES Evaluation Report ESR-2100
  • Passes NFPA 286 without a prescriptive thermal barrier when used in conjunction with Fireshell F10E fire-protective coating
  • Class I fire rated
  • Appendix X compliant without any additional coatings
  • Low odor during application and produces no toxic vapors after application
  • Seals, insulates and minimizes uncontrolled air movement into a building envelope
  • Reduces energy consumption from heating and cooling
  • 245fa-blown, non-ozone depleting agent