Bellwether on Main: A duplex in the heart of Hillsdale New York’s historic district Pre-certified Phius Zero

The Name:

One early activity in Hillsdale was raising sheep, and sending wool to New York City markets. NY 23 was Main Street. Sheep are pack animals, with one leading the flock—a whether. Shepherds would hang a bell on the lead—hence a bellwether. The term came to refer to a leader or trendsetter; hopefully that fits what we are creating here.

Most homes in the United States are built with wood. Yet wood has multiple potential liabilities:

  • fire

  • rot

  • rodents and wood destroying insects

  • mold

  • expansion and contraction

Bellwether is built with autoclaved aerated concrete (AAC), which eliminates multiple hazards of wood construction. It does not, however, grow on trees. Living trees are preferable to lumber for the environment.

In addition to an AAC structure, Bellwether is built with these features:

  • frost protected shallow foundation: reduced excavation and concrete

  • exterior wall insulation: 6” Rockwool Comfortboard 80

  • Ejot thermally broken insulation fasteners

  • Exterior finish: U-Stucco lightweight, hydrophobic, insulating stucco. Though stucco is in the name, it is not a reservoir coating.

  • Interior finish on AAC walls: U-Stucco is also designed as interior plaster

  • Basalt rebar: 2-1/2 times the tensile strength of steel, does not rust, and is one-fifth the weight of steel

  • Triple glazed windows and doors: Access Window and Door Design Centre, Canada

  • Prosoco Fast Flash and Air Dam to seal windows and doors to AAC; no wood bucks

  • Prosoco Adhesive to bond wood to AAC

  • Prosoco concrete sealers

  • Point-sources only for space conditioning; one ductless heat pump per floor in each building TBD

  • SAHP water heaters: solar assisted heat pump water heaters: the Radiant Store, Troy NY

  • Hot water distribution: reduced size tubing: Gary Klein, Gary Klein Associates

  • Energy Recovery Ventilation (ERV): TBD

  • Airtight ceiling membrane: Siga Majrex 200

  • TimberHP ceiling insulation: 24”, ~R80

  • Lighting: low voltage DC LED: LumenCache

  • Stego vapor barrier

  • Amico Global vinyl stucco beads

Two 3” layers of Rockwool Comfortboard 80, Ejot insulation fasteners, U-Stucco mixing, and application in two ¼” passes with fiberglass mesh.

Prosoco Fast Flash; windows are screwed directly to the AAC without wood bucks (Access Window and Door Design Centre); window exterior ready for caulking, interior sealed with Prosoco Air Dam; porch framing in progress.