These modest home designs are fire resistant, featuring metal roofs, cement board siding on the non-bale walls, and plastered bale walls that achieve at least a 2-hour fire rating (most houses don’t have even 1-hour rated walls). All of the home plans comply with the California Building Code for structures in the most extreme Wildland Urban Interface fire zones.
Wee But ‘n’ Ben - This simple 480 sf dwelling that features bale walls on three sides, with the fourth wall in wood framing, where all of the plumbing is located.
“Straw bale walls, when integrated with passive solar design create comfortable dwellings that require a minimal amount of added heating and cooling, due to high insulation levels and the thermal mass of the plaster finish.” suggests David
Arkin, AIA, a principal at ATA, who also serves as director of the California Straw Building Association CASBA. All of the offered homes feature the high insulation level of the bales and thermal mass effect of the plaster finish, and integrated passive solar design techniques that keep most of the hot summer sun out of the building while welcoming the low winter sun.
Through their partnership with www.strawbaleplans.com, anyone interested in these plans who has not lost a home in a recent California Wildfire may purchase them (architectural plans only—engineering is separate) through the website, with a portion of the proceeds going towards making the designs available to fire victims. “We think it is such a great idea what you guys are doing. We want to do what we can to support it,” notes consultant and teacher Andrew Morrison of StrawBale.com
Anni Tilt, AIA adds, “The original owners of these projects have kindly agreed to make their plans available to others ... we wanted to extend that generosity to those who suffered the tragedy of losing a home and most of their belongings in these horrific fires.” Anyone interested in the details of the plans can contact the firm via firstname.lastname@example.org, or at 510-528-9830. Minor modifications can be made at an additional cost, or custom designs can be created through the firm’s modest straw bale plans program, or through full architectural services.
Chalk Bluff Cabin is a 872 sf cabin features a Structural Insulated Panel (SIP) roof structure and an integrated solar hot water and space heating system, storing heat in a 3’ deep sand bed beneath the polished concrete floor slabs. It has a sleeping nook off the living room and another small loft over the kitchen.
Frequently Asked Questions
There doesn’t have to be a difference in the time it takes to build straw bale vs. non-straw bale. The bigger question is the capacity of the builder. Typically the bale-raising has all of the straw bales placed into the wall frames in a single day, perhaps with the builder finishing the following day. The bale walls will then need plaster finish, which is typically a three-coat process. The bale walls are a small part of the big picture.
Is wood framing still used?
Most typically, yes. And all of our plans feature 14” wood I-joists as the vertical framing members, into which the 15” wide rice straw bales are placed. We typically set the vertical plate heights to match a multiple of 23” (the height of a bale when placed ‘on edge’), so there is minimal cutting of custom bale sizes. Most straw bale buildings take into account the typical bale size, and most utilize wood framing. Nearly all of our home designs are a hybrid, with some walls being conventional wood-frame construction.
Can any builder build one of these? What special knowledge/skills/abilities do they need to possess?
The majority of the straw bale homes we’ve designed have been built by builders with no prior straw bale experience. An openness to the technology and general attention to details (which most builders possess) are the only prerequisites. That noted, it will be helpful to have someone familiar with straw bale building to consult with.
Is there a special type of foundation that must be laid?
No and yes. The foundation isn’t different from whatever would otherwise be needed, but both the inner and outer surfaces of the bales need supporting. On slab-on-grade designs the outer sill bears on the perimeter foundation, and the inner sill is on the slab, with a layer of insulation between the two. For the few that have raised floors we typically bear on the joists when perpendicular, or on an extra thick ledger; alternate to this is an extra wide composite lumber sill plate.
Is structural engineering included with the plan?
Unlike the plans being sold on strawbaleplans.com, our structural engineering partner KDSE is providing the structural calculations that accompany the plans free of charge, in most cases. If the extreme circumstances of any particular site require them to modify the calculations and structural design to meet special seismic, high wind or snow load conditions, there may be additional fees plus a few weeks to prepare the changes. For most locations this shouldn’t be necessary.