Camas Magnet Green Building MaterialMichael Dyra, Jared Welch, Garrett Wilgus, Kevin Li

Methodology We constructed small models using our materials: cob, papercrete, sandbags, and fiberglass insulation. These models have walls that are 2 inches thick, 1.5 inches of material and 1.5 of plywood in two sheets. The air space inside was one cubic foot. We tested these using a foam calorimeter to control the external air temperature and measured how long it took for the inside of the models to heat up 1˚ F. We had to limit testing time to 30 minutes due to deadlines. We used Vernier lab equipment to measure the temperature of the inside of the models and inside the calorimeter to ensure validity. The air in the calorimeter will be 115˚ F to simulate a temperature extreme. Our data was taken as the current temperature, which we then used to find average temperature change per hour.

Abstract Alternative building materials are needed for use in building reliable homes in third world countries. We compared cob, papercrete, sandbags, and fiberglass insulation for heat retention. We predicted that sandbags would perform the best based on prior research. Heat transfer was tested by putting the materials in a foam box with 115˚ F air and measuring the heat exchange. Cob proved to have the least heat exchange with only 1.8˚ F per hour, suggesting that it is an excellent insulator in hot weather.

Results When cob was tested, it had lowest heat transfer per hour of 1.89˚ F, averaged from two trials. Papercrete had a change of 2.05˚ F per hour, slightly more change than cob. Sandbag had the highest heat transfer of all the materials with an average of 8.93˚ F per hour. Fiberglass insulation had an average heat change of 4.11˚ F per hour.

Analysis Our data suggest that cob is the best insulator, but this is not the only factor in consideration for its use in Africa. While cob was the best insulator, sandbags hold more potential because it is easier to build, it is bullet and explosive proof, and can be made from local materials. These properties make it good in war torn and impoverished places. Papercrete also faired well in insulation test, but it costs too much to build and ship materials in to countries. Also, all of the materials would have much thicker walls in real application, thus amplifying their insulating capabilities and strength.

Objective It is the goal of the Camas Green Building team to test building materials for humanitarian aid in the form of permanent buildings for people who are without any means or funds to construct one. Our group seeks to design the most effective homes possible to build with minimum resources commonly available in an African village or town. The designs must be low-cost for the sake of funding capabilities, but also meet high quality standards and perform in the field. They must be insulating, structurally sound, and easy to build and maintain.

Impact Our next step is to test insulation, structural integrity, and moisture resistance on larger models made with our materials. Then we will make small houses in eastern Washington which has a climate closer to most third world countries in Africa. These will be tested for longer periods of time. If we garner success, we plan to partner with humanitarian aid organizations that already operate in Africa and get our designs implemented in real world situations.

Acknowledgements We would like to thank Mr. and Mrs. Wilgus for their generosity and help. We would also like to thank Stefan Kracht for his sandbag house blueprints that he kindly gave to us. To Kelly Hart, we owe a particularly long thanks for her advice and knowledge.

Background The materials being used are cob, papercrete, sandbags, and fiberglass insulation. Cob is a mixture of sand, clay, and straw4. Papercrete is made out of recycled paper and Portland cement and it is formed into blocks to build walls3. Sandbag building uses bags full of sand or dirt that are built within frames2. Fiberglass insulation is the standard insulating material for modern homes1.

References1(2005). FAQ's about fiberglass insulation . Retrieved May 3, 2009, from naima.org Web site: http://www.naima.org/pages/resources/faq/faq_fiber.html2Chen, O. (2008, October 10). Affordable and still green: sandbag houses by MMA architects. Inhabitat. Retrieved May 4, 2009 from <http://www.inhabitat.com/2008/10/10/sandbag-house-mma-architects/>3Fuller, B. (2007, January 1). Introduction to papercrete. Living with Paper. Retrieved May 4, 2009 from <http://www.livinginpaper.com/>4Smith, M. G. (2000, January 1). Cob construction. BuildingStandards. 33-35