More Straw Bale Building. Peter Mack
requirement of insurers, so with a permit and fire test ratings, insurance is usually attainable. Some bale homes have even been insured at rates lower than similarly sized conventional homes.
However, it may take the same kind of determination as with lenders to find the right insurer. Your role as educator, confident planner and builder, and well-researched client cannot be underestimated.
Some builders want to have their project insured during construction. In this case, the fire hazards of loose and unplastered straw may cause rates to be higher than with more conventional projects.
Resale Values
In current real estate markets, chances are good that a straw bale home will receive a lower resale value estimate than its frame-walled equivalent. However, low appraisals do not necessarily mean lower resale prices. Home buyers looking for a strong, unique, and super-insulated house may decide that the attractions of a straw bale house are worth more to them than its appraisal indicates. As a side benefit, lower official appraisals often mean lower property taxes.
Since straw bale building is relatively recent, very few homes have traded hands on the real estate market. However, those that have typically sell for the owner’s asking price and within a short time frame. Sometimes it’s an advantage to be selling something unique!
Longevity
The current resurgence of interest in bale construction is due in part to the rediscovery of bale homes in Nebraska dating from the early 1900s, in which the walls have remained strong and relatively unchanged from the day they were built.
The conditions that make for a long and healthy life cycle are the same for any style of construction. Do not expect a bale home to have a shorter life cycle than a wood-framed home. Kept dry, warm, and well maintained, bale homes have easily lasted for 100 years and continue to be strong and healthy. After all, the molecular structure of straw is remarkably similar to that of wood — remember, each bale is thousands of tiny trees bundled together!
Eternally Answering Questions
Straw bale construction excites a lot of curiosity, and with curiosity comes questions. Be prepared to answer red flag questions frequently, since everybody from your mother to the grocery clerk is going to ask them. Consider your patient answers — and your tolerant smile for the inevitable Three Little Pigs joke — an important educational service on behalf of straw bale enthusiasts everywhere!
References
The following list of testing documents will help you provide the information required of you by lenders and insurers:
1) Lerner, Kelly and Pamela Wadsworth Goode, eds. The Building Official’s Guide to Straw-bale Construction, Version 2.1. California Straw Building Association (CASBA), 2000. P.O. Box 1293, Angels Camp, CA, 95222-1293, USA. <www.strawbuilding.org>
This book consolidates an impressive array of tests in one source, and frames these tests with a good introduction and resource section. You can order your copy of this book directly from CASBA <www.strawbuilding.org> or from your usual natural building book distributor. The book includes:
ASTM E72 Compression Test of Plastered Straw Bale Walls, by Matt Fitzgerald Grandsaert, 1999, University of Colorado at Boulder, sponsored by StrawCrafters and the California Straw Building Association.
ASTM E72 80 Compressive, Transverse and Racking Tests of Load-Bearing Walls, conducted under the direction of John Carrick BE, the New South Wales Environmental Protection Agency and John Glassford at the Building Research Centre of the University of New South Wales, Australia, 1998.
Straw Bale Bending and Cement Plaster/Straw Bale Bond Testing, by Jonathan Boynton, 1999, California Polytechnical State University, San Luis Obispo.
In-Plane Lateral Loading of a Stuccoed Straw Bale Wall, by Nathan White and Clint Iwanicha, 1997, California Polytechnic State University, San Luis Obispo.
Straw Bale Vault Test, designed by David Mar, structural engineer, and Skillful Means Architecture and Construction. Conducted by Bill Rothacher and Doug Stark of Consolidated Engineering Laboratories (CEL), 1998, Berkeley, California.
Compressive and Lateral Loading of Straw Bale Walls, by Ghailene Bou-Ali, 1993, University of Arizona.
Thermal and Mechanical Properties of Straw Bales as They Relate to a Straw House, conducted by the Canadian Society of Agricultural Engineering, 1993, Halifax, Nova Scotia, Canada.
Straw Bale Construction Moisture Research, by Joanna Karl, Lis Perlman and Bill Kownacki, 1995, Portland Community College, Oregon.
ASTM E-119 Small Scale Fire Test, by SHB AGRA, 1993, New Mexico.
ASTM E84-98 Surface Burning Characteristics (Flame Spread and Smoke Development) test. (These tests are available for download at DCAT <www.dcat.net> along with DCAT’S explanatory cover sheet).
Thermal Performance of Straw Bale Walls (a summary and discussion of several different thermal performance tests), by Nehemiah Stone and Tav Cummins, 1999, California Energy Commission.
2) King, Bruce, ed. EBNet Conference CD-ROM. Ecological Building Network, 2001. 209 Caledonia St., Sausalito, CA, 94965, USA. <www.ecobuildnetwork.org>
These proceedings from the 2001 EBNet Conference include many papers presented on both straw bale and other natural building methods:
Straw Bale Shear Wall Lateral Load Test, by Jason Nichols and Stan Raap, 2000, California Polytechnic State University, San Luis Obispo, Architectural Engineering Dept.
For the Land of Camels: A Straw Bale Test Wall for Seventeen Foot High Ceiling Structures in the Kingdom of Saudi Arabia, by Chris Stafford, Christopher Stafford Architects, Inc., Port Townsend, Washington.
A Pilot Study Examining the Strength, Compressibility and Serviceability of Rendered Straw Bale Walls for Two-storey Load Bearing Construction, by Michael Faine and Dr. John Zhang, 2000, University of Western Sydney, Australia.
Preliminary Report on the Out-of-plane Testing of an 8-by-8-foot Straw Bale/PISE Wall Panel, by David Arkin and Kevin Donahue, 2001, Mill Valley, California.
Straw Bale Construction: A Review of Testing and Lessons Learned to Date, by Bruce King, 2001.
A Status Report on the Greening of Building Codes and Standards, by David Eisenberg, 2001.
Alternative Building Materials and Systems — Understanding Technical Risk and Uncertainty, by John Straube, 2001.
The Ecological Building Network is currently engaged in the most comprehensive research and testing of bale walls ever undertaken. They report their progress and post their results regularly on their web site, <www.ecobuildnetwork.org>
3) CMHC Testing Reports The Canada Mortgage and Housing Corporation (CMHC) is another valuable source of testing data and documentation. CMHC is a government agency involved in social housing, mortgage insurance, research, and advocacy on housing issues. To this end, they have provided funding for straw bale housing research that has been important and influential.
A sampling of key CMHC tests includes:
Developing and Proof-Testing the “Prestressed Nebraska” Method for Improved Production of Bale Fibre Housing, by Fibrehouse Limited with Scanada Consultants Limited, 1995.
Strawbale Moisture Monitoring Report, by Rob Jolly, 2000.
Moisture