Cream of the Crop
Straw bale construction provides this couple with a fire-resistant, sustainable home that is built to endure.
Written by: Judy Liebner
Photos by: Stuart Bush
Katherine MacNeill and her husband, Duane Hamm, spent several years collecting magazine clippings about straw bale homes, never expecting to build one of their own. A vague desire to leave the city, coupled with an interest in sustainable housing, led to a series of chance encounters and, ultimately, the culmination of a dream.
The couple, who had lived in Richmond, B.C. for more than 20 years, hadn’t seriously considered moving until they vacationed near Penticton. “We stayed around, fell in love with the area and started looking for property, and then we thought it might take us five years to get jobs,” MacNeill recalls.
The couple bought a 10-acre property, located a 51⁄2 hour drive from Richmond, in the south Okanagan Valley. Their plan was to camp there in a tent trailer on weekends, but MacNeill found a new position quickly and she and Hamm set their plans in motion.
The couple believed using fire-resistant, sustainable building materials made good sense because their property is located in a remote treed and grassland area. Straw bale homes have a two-hour fire rating, are resistant to earthquakes and offer an insulation value of at least R-35. They are also cost-effective and can be built for about the same price as a conventional home.
MacNeill and Hamm contracted Henry Yorke Mann to design their home. She knew of him by reputation, and was drawn to the openness of his own home and particularly wanted an open-concept plan that would allow for casual entertaining. It was a happy coincidence that Mann lived very close to the location they wanted to build their home.
“I wanted every room to be useful and part of our life; we wanted light,” MacNeill says.
Mann, who had never designed a straw bale home before, took his inspiration from the setting. He chose sustainable materials, including straw, which is an annually renewable resource, as well as wood, cement-based plaster and cork for the floors.
Ditmar Construction began building the 1,500-square-foot home on July 1st, 2003 and completed it shortly after the couple moved into the home in late December. Hamm also worked on the house and finished much of the woodwork, including the beams. Habib Gonzalez, a straw bale contractor and director of Sustainable Works – which specializes in training builders and designers in plastered straw bale construction – created the interior and exterior straw bale walls.
The home, which is cradled by gentle, rolling hills on three sides, is named ‘Salix’ after the willow species of tree. Salix is also a symbol of the changeable human spirit and immortality, which MacNeill believes is particularly appropriate for her home.
“I feel as though we’ve created something that’s going to be here for years and years, and other people are going to enjoy it, too. It’s going to have a long life,” she adds.
With its deep roof overhangs, the home reveals an Asian influence that is echoed in the design of Hamm’s woodworking shop and a carport. Enormous wood-trimmed picture windows embrace views of meadows, Ponderosa pines, birch and elderberry bushes, effectively blurring the boundaries between indoor and outdoor living spaces.
The interior of the home is distinguished by softly rounded walls, finished with three coats of concrete stucco tinted a pale cream colour. Amber clerestory windows line the perimeter, conveying additional light into the interior.
“When there is light of any kind, it’s warm and it glows all around the outside walls,” says MacNeill.
The front foyer opens directly into the great room, which features a 14-foot vaulted ceiling outlined with heavy spruce and fir beams. The focal point of the room is a massive chimney and surround made of ribbed concrete blocks, attached to a wood stove.
The structure, which is connected to two concrete columns, one on each side, performs a dual function: it supports the roof and adds vertical interest, drawing the eye upward to four skylights and four large pendant lights of amber art glass.
Copper pipes between the ribs of the surround add a reflective quality. “The copper warms up that whole area,” says MacNeill.
A large picture window, shielded by bamboo blinds in summer, stretches across the west wall of the room. Two ceiling fans dissipate warm air from a wood stove, which supplies supplemental heat. Radiant in-floor heating provides the couple’s main heat source in winter.
“The house tends to be cool in summer and very warm in winter. It works just the way it’s supposed to.”
A low wall separates the dining area, positioned at one end of the great room, from a U-shaped
kitchen. Windows line three sides of the workspace, and upper cabinets were minimized to maintain a feeling of lightness. Fir cabinetry and laminate counters that resemble leather create a dramatic contrast between light and dark tones.
A hallway leads from the kitchen past a storage closet and a pantry to the main bathroom that includes a curved fir vanity and a soaker tub with granite skirting. A skylight casts a soft glow and draws attention to the vaulted pine ceiling.
The bathroom is flanked on the left by a guest bedroom and on the right by the master bedroom. A secondary entrance is located across the hall and includes a utility area that conceals a washer and dryer, and a sink and cabinet.
Because of the orientation of the home, the couple enjoys open views from all four sides of the home. There are three patios, accessed from the kitchen, master bedroom and front entry, providing ample outdoor entertaining opportunities.
Mann designed the home to incorporate large sliding windows with low-E glass on at least two sides of every room to provide superior cross ventilation. Aluminum window frames form part of the home’s fireproofing strategy.
The metal roof is light in colour, which allows it to blend into the natural environment and reflect the hot summer sun. The ‘double’ roof consists of four components: a metal roof that serves as a rain-shedding element, a circulating air space, insulation and the structural roof, beams and decking. This design helps to cool the home and avoids the need for air-conditioning.
The deep roof overhangs also help to limit solar gain in summer, while permitting solar heat gain in winter when the sun is at a lower angle in the sky.
“The air comes in at the eaves and exits at the ridges and at the top,” says Mann.
Because straw bales were used for the walls, the sequencing of construction was critical, Mann says. Once the foundation was complete, a series of reinforced concrete columns were poured to support the roof and provide lateral stability. Non-formaldehyde fibreglass insulation was added to the roof structure just before a standing seam metal roof was laid over it. (A standing seam roof is formed on site in such a way that there are no exposed screws that could potentially leak. It’s held in place by clips under the roof.)
“It’s all done right on the site – it’s not formed in a factory,” Mann says.
After the roof was completed, the exterior straw bale walls were raised to ensure the wall components were kept dry. The bales for the walls were laid on edge to reduce the thickness of the walls and save space. They were stacked as if they were load-bearing walls, without internal or external frames, to a height of two metres and topped with a light box beam comprised of three 2×4 studs and sheathed with 1⁄2-inch plywood on both sides.
The walls were then compressed and leveled using high tensile fence wire and fence tensioners. Plaster was used to finish the exterior of the home and the interior walls.
The interior walls are attached at one end to the exterior walls, but are otherwise freestanding. “There’s a real purity around the walls,” Gonzalez says. “These large masonry-covered walls have a wonderful sculpted feel to them.”
While there is some criticism of straw bale homes for being unimaginative boxes, that isn’t the case with Salix House. “It’s just outstanding. It’s a drop-dead gorgeous building,” Gonzalez says.
Hamm agrees. “This material (straw) is pretty fantastic. We just loved it because it gave us a chance to build a house that wasn’t rectangular. Everything is curves and it’s warm and rounded.”
MacNeill advises those who are interested in building a straw bale home to talk to other homeowners. “People who live in a straw bale home just love their homes, and it shows. The best part of this house is how I feel when I’m in it,” she says.