The goal in forthcoming straw bale commercial work is to improve the comfort and health of the built environment while maximizing use of renewable resources and minimizing life-cycle costs. The life-cycle savings are particularly important and a good selling point for institutions that cannot count on increasing income in the future to offset foreseeable large increases in energy costs. Life cycle savings should be developed for alternative cases for the first 50 and 100 years of the building's life. This should be required for all public buildings.
 
Comfort and health, productivity, energy and water use, waste, recyclability, and cost are key issues that should be considered. Systems considerations are critical in building design and operation. The advantages of straw bale buildings (super-insulation, fire resistance, noise control, earthquake safety and durability) are all important considerations for commercial buildings. To take advantage of these features a straw bale building must be well designed for daylighting, natural heating and cooling, natural ventilation, built to last, and easy to monitor and maintain. The rapid reduction in energy use for computers and lights has made heat load management much easier, and straw bale passive solar buildings will reward designers both in winter as heating demand will increase, and in summer as cooling demands drop to manageable levels. The basis of good straw bale commercial design is climatic adaptation.

The basics of climatically adapted design
 
Orientation
Orientation is the key step in design, and even well insulated straw bale buildings risk becoming straw bale ovens if they are not oriented to work with the sun. In the summer the sun is high overhead at noon and rises and sets north of the east-west line. In the winter the sun is much lower at noon and rises and sets further south. These changes make it possible to build a house that is naturally cool in the summer and warm in the winter. A building should face due south (true south not magnetic south) with windows on the south for winter heating, less on the north, and very few exposed windows on the east and west (consistent with safety, ventilation, and views).
 
A rectangle that is longer East-West than North-South is preferred, with interior light wells or courtyards for lighting and ventilation. With overhangs over the south windows to keep the high summer sun out, this type of building will be warmer in winter and cooler in the summer than any other shape. A building with good orientation can save money and will be much more comfortable and pleasant to work in.
 
Early solar designs used many large south facing windows and without adequate thermal mass and shade, these often became solar ovens in the summer. Experience led to houses with more modest window area and much better insulation. Straw bale builders have sometimes assumed the very insulation values would make orientation moot, but they have found that good orientation is critical.

Insulation
Orientation is the first step in any proper design, but without insulation it is difficult to save the heat from a sunny winter day. The walls of straw bale buildings are very well insulated, up to R-70 for "big bale" buildings. Insulation in other elements is usually inexpensive to build in, but much more expensive to retrofit. Typical values might include: ceiling (R-50+ which might be done with bales in some cases), doors (R-7+), and foundation (R-10+). Windows are more challenging. Double pane is the minimal acceptable level (R-2), with insulated shutters or curtains inside. Special heat saving windows with energy control films (such as Heat mirror™) and argon gas are worth consideration. Double pane windows can also be made by doubling up inexpensive single pane windows. A one-to-two inch gap between these windows is sufficient. Skylights can be energy costly, and should generally be minimized unless treated with a SkyLid or other form of movable insulation. South facing clerestory windows are an easy way to get sunlight and solar heat into north rooms. Opportunities for retrofitting many types of commercial buildings appear likely, up to and including curtain wall buildings may exist if we can cost effectively split bales for 12-16 inch thickness. In many cases bales may provide the most effective sound proofing available, for interior sound control (music studios and noisy workspaces) and exterior barriers to airport and highway noise.

Thermal mass
Heat from a cool summer night can be saved for a hot summer day with thermal mass inside the insulated shell. The plaster on straw bales provides considerable mass but this can be augmented with an exposed concrete floor, adobe bancos, masonry, or water tanks that act as thermal batteries. Water walls are the most dynamic storage systems and provide the best performance. Thermal mass also helps save the heat of a sunny winter day for the cold night that follows. The more thermal mass a building has the more stable the temperature will be, but unless it is well oriented and insulated this mass can work against you. A poorly oriented straw bale with high mass will get hotter and hotter inside and will be very hard to cool off. The thermal mass in walls can be set to provide a thermal lag (or delay) that minimizes heat transfer during the middle of the afternoon when commercial buildings may face their peak demand, delaying heat gain until late in the evening.

Weatherization
Heat is also lost or gained by unwanted air flow. This may account for half of the heat loss in a well insulated, but leaky building. Weather-stripping doors and windows, caulking, and sealing can dramatically reduce unwanted heat or cooling loss. The goal is controlled air flow--when and where it is wanted, with sufficient robustness in the system so that people can have and operate their own windows as they wish. In most areas, this type of building (high mass, super-insulation, solar orientation) will work so well that open windows can be used to provide fresh air all year. In very cold climates where the windows must be kept closed, air-to-air heat exchangers should be used to provide fresh air without losing precious warmth. Each office occupant should have a controllable vent. British Columbia solar engineers and designers have developed some very appealing below floor ventilation systems, that provide each occupant with a movable and controllable vent.

Shading
The key to keeping a building cool in the summer is solar control by orientation and shading. Overhangs and arbors will keep the high summer sun out but will let in the low winter sun. Windows on the east and west are more difficult to shade, but shadescreen, arbors, sails, vertical fins, or trees can be used to shade these windows. Backup cooling in commercial buildings can be very efficient in many climates using indirect evaporative cooling. Design guidelines and systems for this were well developed before air conditioning arrived on the scene.

Ventilation
Capturing cooling breezes in the summer requires careful window placement and interior design. Providing both privacy and good air flow is possible. Insulated screened vents can be more economical than movable windows. Interior air flow can be provided with doors cut 1 - 2" above the floor with vents and windows above doors. High ceilings improve the quality of interior space and also improve ventilation. Interior courtyards, atriums and ventilation towers can make ventilating commercial buildings as effective as ventilating homes. Night ventilation of commercial buildings is often easier than ventilation of a home, as fan noise in the early morning hours is less of a concern.

Site modification
The commercial straw bale building should ideally sit where it will have good winter sun, summer shade, summer breezes, and protection from severe winter winds. If a less than ideal site is used it can be improved by landscaping. Sites near noisy streets will benefit from the noise control provided by bales and double or triple pane windows, but outside noise can limit natural ventilation. In most urban environments this may be acceptable, as a HEPA filter with activated carbon prefilter can provide much improved air quality for ventilation air. A bale sound control wall on the property boundary may make it possible to control sound in plazas and offices and allow ventilation. Shade trees to the east and west are helpful, and these can be placed in boxes and beds on decks or landings. Annual vines or grapes can also provide seasonal sun control. Windbreaks, fins and windcatchers can be used to block severe winds and channel cooling breezes into the building.
 
Covered walkways were a standard feature in old towns and cities and provide many benefits for summer cooling and winter heating if they are designed well. Shaded courtyards can be very delightful in the hot summer. A two story courtyard is easier to shade and will ventilate better, but a one story courtyard with a full arbor, vented shadecloth, or large shade tree can be very pleasant. A large unshaded courtyard will be very hot in the summer. Courtyard fountains and streams with falls provide added cooling. Ancient Persian and Arabian cooling relied on water features. Terracotta pots filled with water have also been used to provide evaporative cooling.

The health and productivity benefits of good design
 
Remarkable buildings illustrate what can be done by good design. The key is to focus on productivity gains and health savings, not energy costs which are minor in comparison. Productivity gains often outweigh energy savings 10-20 times or more. For example a 500,000 square foot passive solar, sustainably designed Dutch bank (not straw bale) was built for the same cost as conventional construction but it uses less than one tenth as much energy, absenteeism is 15% lower, and the bank business has dramatically increased due to the visibility and success of the building. Productivity gains from good interior daylight and comfort are often 15-20% and employee absences and turnover are also reduced. Students in comparison studies showed a 10-15% increase in learning when classes were held in well designed daylit buildings. The productivity benefits will often provide 10 times the dollar benefit of the energy savings. Most buildings could realize similar savings.
 
San Diego buildings should require minimal cooling systems and no heating systems. All windows should open up to the 3rd floor. Daylight codes like those in Europe, 21 feet to the closest window should also be adopted. During its lifetime the cost of energy for a building may exceed the initial cost, but careful design and construction can dramatically reduce energy In British Columbia solar buildings are being built at the cost of conventional construction with 50% reduction in energy use. For an added cost premium of 10-20% energy use can usually be cut 80-90%. The life cycle savings are enormous!

Other goals of system integration

Water conservation and water harvesting: Low water use fixtures, and appliances, and landscaping, composting toilet, graywater reuse. Buildings should harvest rainwater to reduce stormwater problems and provide on-site thermal mass and water for landscaping. Water treatment for large buildings with biotreatment facilities and reverse osmosis would be much better than current heavily subsidized, expensive, and inflexible regional plants.

Recyclability: A large percentage of landfill waste (up to 40%) is construction debris. The designer should consider the end of life of a building as well, how can it be reused, recycled or disposed of safely and economically.

Why aren't many commercial buildings already straw bale?
 
Amory Lovins from the Rocky Mountain Institute has described many of the perfectly perverse incentives that encourage almost everyone in the process to do the wrong thing. These small but important signals and incentives make it most profitable for the designers, engineers, builders and installers to make inefficient, costly and unhealthful buildings. This has been compounded by poor training in schools, (architecture, engineering, economics and business, landscape architecture).

Four key problems include:
 
1) Subsidized power and material costs and separation of users from production costs encourage poor design. Government subsidies artificially reduce the cost of energy, water and building materials to 10-25% of their true cost. A bad building will often increase peak loads in August at the peak use period, this can require new generating capacity-perhaps as much as $100,000 dollars, but the architect or engineer doesn't pay it, other utility customers do. The price jump in San Diego for electricity, to more than 25¢ kwh this summer, would encourage use of daylighting and climate resources if designers were not confident these price hikes would be repealed.

2) Dominance by the developer rather than users or clients. The developer is usually forced into making minimal first cost the key goal (financing pressure is high) -- without considering life cycle costs or comfort and productivity. Minimizing cost in the short term maximizes cost in the long life of a building. Renters and buyers pay for these mistakes for decades.

3) Failure to consider system integration is one of the biggest problems, and even a few straw bale designers have neglected this factor. The lighting engineer may design lighting for minimal installed cost, without considering possible use of natural daylighting (determined by the architect's window choices) or the cost of cooling to offset lighting heat (90% for incandescent lights). The architect may design the building without consulting the mechanical engineer about the implications for natural heating and cooling or daylighting. And user comfort and productivity is rarely an issue --- almost no post construction analysis is ever done. Integration and teamwork are essential to make buildings better!

4) Tax rules on depreciation and investment often encourage minimal planning for energy and maintenance costs -- which can be passed on to users. Users are reluctant to invest in efficiency improvements in buildings they don't own. Depreciation rules makes building decay acceptable. The 100 year mortgages used in Japan and Sweden may be a useful tool in the struggle against poorly built and inefficient buildings.

What are the technical challenges?

Although large straw bale commercial buildings could and are being built today, several interesting challenges remain. These include: better understanding of the seismic performance of large load bearing or steel frame and bale buildings, optimized building systems to reduce bale handling costs, bale handing strategies for standard and large bales (4 ft x 4 ft x 8 ft, and 8 ft x 3 ft x 3 ft) on multilevel buildings; bale splitting to provide smaller cross section materials, optimized plastering systems (band saws), straw bale moisture fluxes over time, and retrofitting commercial buildings with straw bale passive solar systems.
 
Improved sensors and microcomputer management can improve understanding and performance and pinpoint problems. These innovative systems also make performance based retrofits possible. These new sensors also will make it possible to have readily visible meters, displaying relevant data on energy use, energy costs and savings, moisture in bales, and thermal performance.
 
One of the most useful projects I think CASBA could undertake is providing a workbook on commercial construction projects and encouraging discussion of bigger and more ambitious projects. Schools, universities, the Department of Defense, hotels and restaurants, casinos, museums, warehouses, and office buildings are all promising candidates for straw bale construction.

Further Reading:

Bahadori, M.N. 1978. Passive cooling systems in Iranian architecture. Scientific
     American 144-154.
Bainbridge, D.A. 1978. Natural cooling: practical use of climate resources for
     space conditioning in California. Pp 138-153. In E.F. Clark, and F. de Winter,
     eds. Proceedings of the 3rd Workshop on the Use of Solar Energy for the
     Cooling of Buildings, San Francisco, California, U.S. Department of
     Energy/University of Colorado, Boulder.
Bainbridge, D.A. 1979. Waterwall passive solar systems for new and retrofit
     buildings. pp 473-478. In Proceedings of the Third Passive Solar Conference,
     American Section International Solar Energy Association, San Jose, California.
Bainbridge, D.A. 1983. Water Wall Solar Design Manual. SUN, Bascom, Ohio.
Bainbridge, D.A. 1987. Energy self-reliant neighborhoods. pp. 398-402. In D.A.
     Andrejko and J. Hayes, eds. 12th Passive Solar Conference Proceedings,
     American Section International Solar Energy Society (ASISES), Boulder,
     Colorado.
Bainbridge, D.A., J. Corbett, and J. Hofacre. 1979. Village Homes' Solar House
     Designs, Rodale Press, Emmaus, PA.
Butti, K. and J. Perlin. 1980. A Golden Thread. Chesire Books.
Cramer, R.D. and L.W. Neubauer. 1959. Solar radiant gains through directional
     glass exposure. ASHRAE Transactions V65: #1681.
Cramer, R.D. and L.W. Neubauer. 1966. Thermal effectiveness of shape. Solar
     Energy 10(3):141-149.
Edminster, A. 1995. Strawbale construction: investigation of environmental
     impacts. A.V. Edminster design. Pacifica, CA. 115 p. thesis
     [avedminster@earthlink.net]
Elizabeth, L. and C. Adams. 2000. Alternative Construction: Contemporary
     natural Building Methods. John Wiley, NY 392 p.
Eisenberg, D. 1995. Straw Bale Construction and the Building Codes.
     Development Center for Appropriate Technology, Tucson, AZ.
     [http://www.azstarnet.com/~dcat/barriers.htm]
Evans, B. 1954. Natural air flow around buildings. Research Report #59. Texas
     A&M, College Station Texas.
Givoni, B. 1969. Man, Climate and Architecture. Elsevier
Glassford, J. 2000. Monica's Winery. Details on big bale and sb construction in
     Australia. [http://strawbale.archinet.com.au] or [huffnpuff@shoal.net.au] 
Haggard, K. and S. Clark, eds. 1999. Straw Bale Construction Sourcebook.
     California Straw Building Association/San Luis Obispo Sustainability Group.
     Santa Margarita, CA37 p.
King, B. 1996. Buildings of Earth and Straw: Structural Design for Rammed Earth
     and Straw Bale Houses. Ecological Design Press/ dist. by Chelsea Green
     Press, White River Junction, VT. 169 p.
Lerner, K. and P.W. Goode. 2000. The Building Official's Guide to Straw Bale
     Construction v2.1. California Straw Building Association, CA 83 p.
     [http://www.strawbuilding.org]
Neubauer, L.W. 1972. Shapes and orientations of houses for natural cooling.
     Transactions ASAE 15(1):126-128.
Neubauer, L.W. and R.D. Cramer. 1968. Effect of shape of building on interior air
     temperature. Transactions ASAE 11(4):537-539.
Niles, P., K. Haggard, and P. Cooper, eds. 1980. California Passive Solar
     Handbook. California Energy Commission, Sacramento, California
Magwood, C. and P. Mack. 2000. Straw Bale Building. How to plan, design and
     build with straw. New Society Publishers, Gabriola Island, British Columbia.
     234 p.
Myhrman, M. and S.O. MacDonald. 1997. Build it with Bales, version 2. Out On
     Bale, Tucson, AZ. 143 p.
Olgyay, V. and A. 1976. Solar Control and Shading Devices. Princeton Univ.,
     Princeton, N.J
Steen, A. and B., D.A. Bainbridge, D. Eisenberg. 1994. The Straw Bale House.
     Chelsea Green, White River Junction, VT. 297 p. 
 

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