STRAW-BALE AS A VIABLE, COST EFFECTIVE, AND SUSTAINABLE BUILDING MATERIAL FOR USE IN SOUTHEAST OHIO A thesis presented to the faculty of the College of Arts and Sciences of Ohio University In partial fulfillment of the requirements for the degree Masters of Science Leanne R. Marks June 2005 This thesis entitled STRAW-BALE AS A VIABLE COST EFFECTIVE AND SUSTAINABLE BUILDING MATERIAL FOR USE IN SOUTHEAST OHIO by LEANNE R. MARKS has been approved for the Program of Environmental Studies and the College of Arts and Sciences by Christopher Boone Associate Professor of Geography Leslie A. Flemming Dean of College of Arts and Sciences Marks, Leanne R. M.S. June 2005. Environmental Studies. Straw-Bale as a Viable, Cost Effective, and Sustainable Building Material for use in Southeast Ohio. (118pp.) Director of Thesis: Christopher Boone In Southeast Ohio, the humidity is relatively high all year round; the maximum monthly average humidity readings exceeded 80% during the ten months of sampling. Precipitation levels, and its’ effect on moisture accumulation within straw-bale walls, had been a concern to individuals skeptical about the use of straw-bales as a viable building material. Athens County, Ohio, is located within the Appalachian region, a poverty stricken region that desperately requires livable, affordable housing. Throughout this document, it becomes evident that straw-bale construction is in fact, a viable, cost effective and sustainable and safe building method for use in southeast Ohio. Within the study the moisture content of three Athens County straw-bale homes were recorded during a ten-month period (Dec. 2001–Sept. 2002.) The daily weather data was also recorded on-site and collected from Ohio University’s Scalia Lab. The results were grouped into monthly averages, to compare different areas of the houses to other areas, other houses, and correlate to the weather data. It was discovered that when straw-bale buildings are constructed using the correct and specific techniques, moisture intrusion did not seem to be detrimental to the health of the building, regardless of environmental location. The elevated moisture readings resulted from a variety of causes including: Lack of toe-up, Unstuccoed wall sections, Inappropriate footer system, Use of moisture barriers between straw-bales and stucco, and Insufficient overhangs. Approved: Christopher Boone Associate Professor of Geography 5 TABLE OF CONTENTS I. HISTORY OF BUILDING WITH STRAW................................................. 11 II. WHAT EXACTLY IS STRAW?................................................................ 14 III. FIRE RESISTANCE ................................................................................. 17 IV. INSULATIVE PROPERTIES .................................................................... 18 V. CURRENT BUILDING SITUATION AND ENVIRONMENTAL CONCERNS............................................................................................. 22 VI. AFFORDABILITY..................................................................................... 29 VII. WALL COVERINGS................................................................................. 40 TYPES OF STUCCO................................................................................................ 43 i. Cement Stucco...................................................................................... 43 ii. Lime Plaster .......................................................................................... 45 iii. Earth Plaster.......................................................................................... 48 VIII. STUCCOES AND MOISTURE................................................................. 50 IX. MOISTURE MIGRATION AND ACCUMULATION IN BUILDING ENVELOPES RELATIVE TO STRAW-BALED WALLS ....................... 54 X. FORMS OF MOISTURE .......................................................................... 55 XI. SOURCES OF MOISTURE ..................................................................... 58 INTERIOR SOURCES .............................................................................................. 58 EXTERIOR SOURCES ............................................................................................. 62 GROUND SOURCES ............................................................................................... 66 XII. METHODOLOGY..................................................................................... 68 HOUSE DESCRIPTIONS .......................................................................................... 68 i. House No. 1 .......................................................................................... 69 ii. House No. 2 .......................................................................................... 72 iii. House No. 3 .......................................................................................... 74 6 INSTRUMENTATION ................................................................................................ 76 SAMPLING PROCEDURE ......................................................................................... 77 AREAS TESTED THAT WERE CONSIDERED TO BE VULNERABLE TO MOISTURE INTRUSION ................................................................................................. 78 DATA COLLECTION LOCATIONS .............................................................................. 79 i. Southwest Wall Section......................................................................... 79 ii. Northeast Wall Section.......................................................................... 79 iii. Eastern Wall Section ............................................................................. 80 iv. House No. 3 Alterations......................................................................... 81 XIII. DATA ANALYSIS .................................................................................... 83 XIV. RESULTS ................................................................................................ 84 INDIVIDUAL DATA COLLECTED ................................................................................ 84 MONTHLY AVERAGES COMPARISONS...................................................................... 87 EXTERIOR READINGS VS. INTERIOR READINGS ......................................................... 91 WALL ALTITUDE COMPARISONS ............................................................................. 95 i. Top Wall Sections ................................................................................. 96 ii. Mid Wall Sections.................................................................................. 97 iii. Bottom Wall Sections ............................................................................ 97 XV. WEATHER DATA ANALYSIS................................................................. 99 TEMPERATURE...................................................................................................... 99 RELATIVE HUMIDITY - MOMENT AND MAXIMUM ....................................................... 101 PRECIPITATION ................................................................................................... 102 XVI. CONCLUSION ....................................................................................... 104 XVII. DISCUSSION......................................................................................... 108 XVIII. REFERENCES....................................................................................... 111 7 LIST OF TABLES Table 1 Straw Yield in Ohio............................................................................. 16 Table 2. Constructional Materials and Their Environmental Impact ................. 28 Table 3. Projected long-term life-cycle costs of straw-bale buildings compared to conventional buildings.................................................................... 30 Table 4 Vapor Permeance of Wall Covering Materials.................................... 52 Table 5. Household vapor accumulation.......................................................... 61 Table 6. House No.1 Monthly Average Moisture Content Readings ................ 84 Table 7. House No.2 Monthly Average Moisture Content Readings ................ 85 Table 8. House No.3 Monthly Average Moisture Content Readings ................ 86 Table 9. House No.1 interior vs. exterior averages .......................................... 91 Table 10. House No.2 Interior vs. Exterior ......................................................... 92 Table 11. House No.3 Exterior vs. Interior ......................................................... 94 Table 12. Wall Altitude Averages ....................................................................... 95 Table 13. Monthly Average Weather Data ......................................................... 99 8 LIST OF FIGURES Figure 1. Re-make of an early 19th century straw-bale home. .......................... 11 Figure 2. The first straw-bale church, Arthur NE (1920). .................................. 13 Figure 3. A typical two-string straw-bale............................................................ 14 Figure 4. A chicken wire enclosed straw-bale wall. ........................................... 15 Figure 5. 2,000sqft straw-bale home in Ohio..................................................... 20 Figure 6. Deforested land in the Midwest. ......................................................... 23 Figure 7. Degraded straw-bales. ......................................................................