#Like an old fashioned barn-raising, this home was built with many hands
Built before LEED and most green guideline programs existed, this largely straw-bale house in Minnesota established new building codes with its creation. Its biggest sustainable attribute may well be its collaborative approach.
Straw—a beautiful, hand-crafted material
In 1995, Ken and Laura had the idea of building a house on the north end of a meadow, on nine acres of forested land that descends at one end to the North Branch of the Sunrise River. With their long time friend, architect and builder Jonathan Query of the design/build company IIIAD, they determined it should minimize ecologic impact, be sourced locally, and cost little to heat and maintain. Having a limited budget, they also decided to use as much of their own and volunteer labor as possible.
This led them to straw bale and stucco, which they all knew little about. However, it held promise as a craft that they and others could learn quickly. Thus they, and the core construction team of friends and family, found themselves hosting workshops for an energetic group of volunteers over the 1996-97 building season. Together, they set courses of straw bale on vertical rebar pins and sewed chicken wire mesh to both sides of the wall with 3’ steel ‘bale needles’. With many friendly gloved hands, they slapped up three coats of fly-ash stucco on the exterior and slaked lime plaster on the interior.
Keeping it close to home
Using agrarian references, simple forms and a hybrid of materials, the house is centered on a three story stair tower which acts as a ventilation chimney. Constructed of 4” x 4” cedar, its columns are exposed on the inside and house deep drawers that nest with each tread and riser. Ken, who is also a cabinetmaker, made these in the straw bale, Quonset-roofed shop at the meadow entry, which was built first to accommodate indoor fabrication tasks. The rest of the house is post and beam, with a couple of small bump-outs in standard 2” x 6” wood studs.
The first floor would be concrete slab on rigid insulation if they were to do it again, but they went to great effort to make a sub-slab of straw bale and poured concrete (called a waffle slab). They now feel it represents too much labor and concrete to be worth the effort. The second floor is concrete poured on structural steel decking, for durability and ease of installation. Ken dyed all floors with iron sulfate and polished them to a rich sheen.
Some interior delights include columns sourced from a telephone pole fabricator, bought as rejects for the grand price of $1 per linear foot. All of the roofs and the elegant beams of what they call their ‘harvest room’ are resawn timbers from an 1890s creamery.
The home is so warm on account of the straw bale insulation that the sub-floor zoned hydronic heating system is used infrequently. Most of the heat needed comes from a Danish Jotul wood stove, which consumes two cords of wood (mostly oak) per frigid Minnesota winter. Walls with an R45 or R50 value, ranging in thickness from 18” to 22”, keep all 2560 square feet toasty. Additionally, about 400 gallons of propane per year are used for stove, clothes dryer, and domestic hot water.
Building your own house by hand is not for the faint of heart. The straw bale construction did not really result in cost reductions. But the volunteer work did, and they found it was joyous, arduous fun. An early and brutal winter blew away the hope of getting the house closed in before bad weather. They struggled to keep the straw bales dry and finish it under a heated tent that storms periodically ripped away. Come spring, they were forced to drill thousands of holes in the stucco to dry it out, and in places, remove decayed, rotten straw. Ken says the most important thing he wants to share about straw bale building is that in northern climates, the top of a wall has to be directly vented to the outside or an attic, even if moisture never touches the straw.
The inventive and artistic owners love the thick, shapeable walls, which they sculpted for playfulness and drama. They are pleased that many reclaimed elements in their house, like the magnificent creamery beams, may one day live in a third incarnation. They hope that the house itself will endure, like Nebraska’s 19th century straw bale homes—many with only a little flaking plaster, some 200 years on.
General Specs and Team
|Location:||North Branch, MN|
|Additional Notes:||House: 2560 sq.ft.
Cabinetry shop: 1,900 sq. ft.
Total cost: $150,000 (mostly volunteer labor)
Architect/designer: Jonathan Query, III AD
Builder: III AD, Ken the Rickettes Builders, plus lots of lively volunteers
Engineer: David Morris
Foundation: perimeter grade beam (shallow frost-protected foundation with 2-in. XPS rigid foam apron; slab on grade for both structures (R-10); straw bale cast in slab for house (R-45)
Walls: Straw bale (nonload-bearing, with modified box columns of 2x4s sheathed on all sides with 1/2-in. plywood); some 2x6 framing; timber frame interior columns, 4x4 cedar columns in stair tower; bale walls, R-45; 2x6 with fiberglass batts and 1-n. XPS foam on exterior (R-45); timber frame infilled with 4-in. polyisocyanurate rigid foam (R-21)
Windows: argon-filled, low-e (Marvin Integrity)
Roof: timber frame with structural steel decking covered in 5-1/2-in. polyisocyanurate rigid foam and standing seam metal roofing (R-45)
Garage: detached carport
- Long east/west axis optimizes solar gain
- Generous eaves (3 ft. to 4 ft.) to augment thermal mass gradient
- Energy star appliances
- Some CFLs
Heating/cooling/water: radiant floor heat, zoned; Combi-core hydrojet propane water heater (46-gal.) for radiant heat and domestic hot water (Bradford White); wood stove (Jotul); passive ventilation; back-up split-system air-conditioning unit with dehumidifier (Goodman);
Annual energy use: 92.5 MMBtu; approx. 2 cords of mostly red oak; 400 gallons propane and 2500-kWh electricity
- Low-flow showerheads
Indoor Air Quality
- Low-VOC finishes
- Whole-house passive ventilation
- Heat-recovery ventilator (Broan)
Green Materials and Resource Efficiency
- Straw-bale construction
- Reclaimed timber framing
- Job-site recycling close to 100%
- Advanced hybrid framing
- 30% fly-ash stucco
- Minimal site disturbance
- Natural materials used wherever possible
- No MDF or particleboard
First code-approved straw bale residence in Minnesota