Straw Bale Home
Site characteristics or focus during construction: Our project focused on building a modestly sized, comfortable, healthy, energy and water efficient home using as many green, durable and recycled materials as practical. Early in the design stage we decided to detach the garage and locate the house further back on the property, providing more privacy. The site is forested and we left all the healthy trees at the street (west) side of the property in order to provide a noise and visual buffer from Northwoods Blvd. We located the house on the north side of the property, taking advantage of an existing clearing to the south for passive solar gain. The hiking trail across the street provides easy walking access to
the Tahoe Donner Clubhouse and the Trout Creek Recreation Center.
Construction Types: Exterior walls consist of a “post and beam” vertical structural system, HardyFrame brace frame lateral structural system, and 2-string rice straw bale infill (18” thick). Insulated concrete forms (TF system) at stemwalls and retaining walls provide energy efficiency (R 25) and ease of construction. The framing lumber, finish wood, ipe decking and pre-fabricated trusses are sustainably harvested, certified by the Forest Stewardship Council(FSC). The house and garage are engineered to minimize the amount of wood required and to use composite products. Stained concrete slab on grade at first level provides mass (for solar and hydronic radiant heat), structure and finish. Ceramic tile and EcoTimber bamboo flooring over gypsum underlayment provide mass and durability at second level.
Passive Solar System: South facing windows collect solar gain and the floor and wall mass absorb, store and slowly release the heat. Our site is forested resulting in some solar obstruction, but we are determined to take advantage of the sun we have available.
Active Solar System: Two thermal collectors will provide solar domestic hot water.
Main Heating System: Passive solar.
Auxiliary Heating System: Hydronic radiant floor system with natural gas fired boiler. Tubing runs south to north in each zone, so system can be operated without the boiler to circulate solar heat. Hearthstone woodstove provides supplemental quick response heat and has soapstone for mass.
- Modestly sized.
- R-49 Ultratouch cotton batt insulation at roof, R-23 strawbale exterior walls/
- Tight construction with energy recovery ventilator.
- High performance fiberglass windows with low E high solar transmittance.
- Fluorescent and compact fluorescent lights wherever practical.
- The kitchen features a recycling center and energy efficient appliances.
- Clothes drying rack in laundry room.
- Water conservation features include low flush.
An energy recovery ventilator (ERV) replaces
stale indoor air with fresh outdoor air while transferring heat and humidity.
- Durable concrete and tile floors and central
vacuum system enhance indoor air quality and reduce allergens.
EPA-certified Hearthstone woodstove provides supplemental quick response heat
and has soapstone mass to help distribute heat evenly.
- FSC certified lumber.
- Specified concrete with fly ash at footings (25%) and slabs (20%).
- EcoShake 100% recycled content Class A roofing with50 year warranty.
- Durable carpet less flooring and central vacuum system provide improved indoor air quality and reduce allergens.
- Hydraulic lime plaster with homemade lime wash at exterior, self made earthen plasters with natural casein and clay paints at interior, natural oil finish at woodwork.
Photos by Joel Erickson
Owner: Bill &
Size: 1,954 sq
ft living space 576
sq ft garage
Designer: EcoEngineering/ Darcey Donovan
Builder: Bill Donovan,
Date of Construction: