Assessing the perception of compressed earth block (CEB) among contractors in the Piedmont region of North Carolina
Date
2015
Authors
Hughes, Evan G., author
Valdes-Vasquez, Rodolfo, advisor
Vaske, Jerry, committee member
Elliott, Jonathan, committee member
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Abstract
The earliest earthen dwellings in the U.S were made by manually pressing a mixture of moist earth and straw into wooden molds to produce roughhewn blocks, which were left to dry in the sun before being stacked and mortared with earth slurry. This method, known as adobe, is free of volatile organic compounds (VOCs), is less energy-intensive than concrete and steel, and allows for local block production if the soil meets certain criteria. However, adobe construction requires more time and manual labor than most conventional materials, and as a result has been largely ignored by U.S. contractors with the exception of those working in New Mexico. This is true of most earthen building techniques, including compressed earth block (CEB). CEB retains many of the environmental benefits of adobe, but unlike adobe CEB can be produced with automated soil mixers and hydraulic presses, allowing for rapid and consistent block production in large volumes. Despite these advantages, CEB remains relatively unknown, occupying only a niche market in certain regions of the country. With the advent of labor and time-saving technology, the practical barriers presented by traditional earth building methods have been greatly reduced, necessitating an exploration of the non-technical barriers to CEB acceptance and adoption in the U.S. Studies conducted in Africa and Southeast Asia have shown that home-buyers often associate earthen structures with poverty, transience, and poor performance. While research on earthen block construction is limited in the U.S., studies performed in Midwestern states have indicated similar results. The current study seeks to determine what, if any, perception barriers to CEB acceptance and adoption exist among contractors in the North Carolina Piedmont region, which lies between the Appalachian Mountains to the west and the Atlantic coastal plain to the east. The Piedmont was chosen because the soil of the region is rich in non-expansive clay that is well-suited to earthen construction in humid climates. Despite these favorable conditions, the North Carolina Piedmont has yet to develop a significant market for earthen architecture and virtually no research has been conducted to investigate this phenomenon. To address this gap in the research, a survey instrument was designed and piloted in New Mexico. Pilot data and feedback were used to refine the survey instrument, which was then distributed to general contractors in the Piedmont. A third survey was distributed to select contacts in the researcher’s professional network to compare the perceptions of building professionals with experience using CEB to those of general contractors in North Carolina with little to no CEB experience. These surveys, based on instruments developed in previous research, aimed to assess contractors’ awareness of CEB, their experience with CEB, and their perception of CEB’s practical merits and drawbacks. Two telephone interviews were also conducted, one with a North Carolina contractor who specializes in CEB construction and another with a Texas-based manufacturer of automated CEB block presses. Quantitative data gathered from survey distributions in the Piedmont and within the researcher’s network revealed disparate opinions of CEB’s cost-effectiveness, aesthetic value, and structural worth. Respondents with no CEB experience provided largely neutral opinions in these areas, indicating that they may have been unable or unwilling to provide definitive positive or negative opinions due to their lack of experience with the material. Responses from those who had used CEB were either neutral or positive. Qualitative data gathered from these two survey distributions indicated a similar divergence of opinion between respondents who had used the material and those who had not. When asked to provide the first three words they associate with CEB, respondents with no CEB experience associated the material with a wide variety of terms, such as “mud,” “costly,” “hippie,” and “future.” Respondents who had used the material associated it with positive terms and technical properties, such as “non-cementitious” “non-toxic,” and “fire-proof.” This suggests that A.) These respondents may have gained a better understanding of CEB’s technical properties after using it in professional practice, or B.) They have become accustomed to providing these technical properties to skeptical clients or their peers. Both phone interview subjects, despite their differences in profession and geographic location, recommended increased education and exposure to CEB to overcome skepticism and lack of knowledge among the construction industry and the general public. The results of this study assist building professionals and their clients in understanding how non-technical barriers (i.e. barriers not related to time, infrastructure, technology, or capital) may impede the acceptance and adoption of CEB and other non-conventional materials. Identifying and addressing these barriers is a necessary step for increased market penetration of CEB in the North Carolina Piedmont and elsewhere.
Description
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Subject
earth architecture
non-technical barriers
compressed earth block
perception
non-conventional materials