Grantee Research Project Results

Final Report: Comparing the Sustainability of a Compressed Earth Block House to a Conventionally Framed House Built to National Green Building Standards

EPA Grant Number: SU835289
Title: Comparing the Sustainability of a Compressed Earth Block House to a Conventionally Framed House Built to National Green Building Standards
Investigators: Holliday, Lisa M. , Graham, Charles , Butko, Daniel J. , Williams, Scott , Crandall, Aaron , Sivuilu, Herve , DeFreitas, Kyle , Snow, Holly , Mall, Peter , Curtis, Stephen , Frame, Michael , Waddle, Jesse , Kincanon, Kymber , Palmer, Jared , Huor, David
Institution: University of Oklahoma
EPA Project Officer: Hahn, Intaek
Phase: II
Project Period: August 15, 2012 through August 14, 2014 (Extended to February 14, 2015)
Project Amount: $89,721
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2012) Recipients Lists
Research Category: P3 Challenge Area - Air Quality , Pollution Prevention/Sustainable Development , P3 Awards , Sustainable and Healthy Communities

Objective:

The objective of this multi-phase research project was to produce new knowledge and develop best practices for CEB construction processes. This may enable broad implementation of CEB technology in domestic and international housing construction. The CEB construction methods are comparatively simple for individuals and social organizations that rely on volunteer labor, such as Habitat for Humanity and other community organizations. CEBs are inherently sustainable, economical, and energy efficient. They require little energy to produce, conserve natural resources, vastly reduce landfill waste, and reduce energy consumption required for residential heating and cooling. With appropriate reinforcement, they have been proven structurally sound even in earthquake prone areas. CEB construction has been demonstrated as a viable residential construction solution in Oklahoma (harsh winters, hot summers, and strong winds), and is believed to be a viable option for almost any location in the developed or developing world.

Summary/Accomplishments (Outputs/Outcomes):

• Finish an architectural mockup wall showing construction details as a teaching tool on Campus.
  • The mock-up was completed in the summer of 2012.
• Finish construction documents (very comprehensive set of drawings since many CEB details are not used in common building practices). Construction drawings were completed prior to building the house.
  • Details from these drawings were published in the Earth USA conference in 2013 and more will be published in the 2015 conference.
• Obtain building permit and finalize cost analysis.
  • A building permit was obtained in February 2013.
• Finish producing CEBs for the house using logistics and equipment developed in Phase I with CCHFH volunteers and waste soil from nearby commercial construction sites.
  • All blocks were made for the project and this was completed in summer 2013.
• Break ground on the CEB house with local volunteers, students, and faculty.
  • The ground breaking ceremony was held on March 9, 2013.
• Build the CEB house based on test results and knowledge learned during Phase I.
  • The CEB house was built and the homewners moved in Octber 2014.
• Have a P3 student team member as the n-site Prjoect Manager who helps involve the entire team throughut the building process
  • Several graduate and undergraduate students filled this role.
• Instrument both the CEB house and the adjacent control house to compare structural performance, energy consumption, thermal properties, indoor air quality, acustical attributes, and ther sustainable properties.
  • The CEB house and the control house are both instrumented.
• Set both house thermostats equally to compare energy use and resultant efficiency (during the test period, the team plans to subsidize electric and gas bills spanning heating and cooling periods as concessions for both househlds to ensure equality among testing).
  • The homewners have agreed to the thermostat settings and have been each paid $400 to compensate them for any inconvenience.
• Compare the livability of the two homes based on tenant comments.
  • This is onging and will continue in the future, but the Ruvalcaba family was at one piont given the chioce of the traditionally wood-framed adjacent house which at the time could have been completed earlier, but the family chose to wait for the CEB house.
• Compile best practices and documentation of results.
  • Several publications have been printed, but the final compilation of results will result in the next Earth USA conference (the only earth building conference in the US and occurs every other year) in Octber 2015.

Conclusions:

• Streamlined life cycle costing and analysis, if appropriate
  • We found it difficult to calculate the construction cost difference between the CEB house and the control house because much of the materials are donated to Habitat for Humanity and the labor is also donated. We estimate the CEB house to cost 10% more than a similar conventionally built house of the same volume.
• Quantifiable benefits to people, prosperity, and the planet (estimated or actual)
  • The quantifiable benefits in terms of carbon footprint have been measured. However the energy savings will continue to be measured over the next year. We expect the summer to be the high energy demand time that will determine the energy savings.
  • The acoustic benefits are as follows:
    • As defined in the October 2014 progress report, the 8 dBA difference between the CEB wall and the wood-framed wall is quite significant since every 10 dBA is considered a doubling or halving the comparatively measured sound source. The NIC field tests provided data to support the initial belief the CEB walls would provide more isolation between interior and exterior sources while defining the CEB wall to provide almost twice the sound loss when compared to the wood-framed wall, without compromising the necessary audible alert of storm warning sirens which still arrive to interior spaces through the roof assembly, doors, and windows. The team will continue the acoustical data collection through a relationship with ETS-Lindgren's acoustical testing laboratory in Cedar Park, Texas in which team member Daniel Butko has previously visited and arranged further testing. The laboratory data will complement the field data to ultimately provide STC and TL values for publication. ETS's website: http://www.ets-lindgren.com
  • Aside from the collected data, the 0.1 NRC value of the interiorAmerican Clayplaster is enhanced through keying tightly into the 12" thick dense CEB. The compound density provides strong lateral acoustical reflections to the interior spaces resulting in less sound energy being lost into or absorbed through the wall assemblies. The reflections define a particular acoustical warmth to the spaces since more of the low frequency energy is reflected back into the interior spaces, supporting the acoustical descriptive terms warmth, embodiment, and intimacy. Voices and sound sources do not need to be as loud compared to the wood-framed residence since most of the energy continues to reflect along/across the reflective wall surfaces. The acoustical presence in the CEB residence adds a particular ambiance to the overall character of the space which is immediately realized by visitors to both residences. The acoustical properties of the built environment have a direct impact on occupant health and welfare.
• Qualitative benefits to people, prosperity, and the planet
  • Most people who enter both houses agree the CEB house feels and looks better. The interior is more comfortable, the plastered walls give a warm feeling, and the deep window and door recesses created by the CEB thickness defines a perceived strength to the enclosure.
• Other pertinent information, including, if appropriate, analysis and explanation of cost overruns or high unit costs.
  • The timeline was delayed due to several factors beyond our control including CCHFH project schedule and a serious tornado in the area. The project remained on budget, however funds were not spent exactly as estimated. Some items were donated which helped the budget while other items were underestimated. All in all, budget overruns and budget savings canceled one another. Ultimately, the two completed houses are now homes for two well-deserving families.

Journal Articles:

No journal articles submitted with this report: View all 11 publications for this project

Supplemental Keywords:

Alternative Construction Material, Earthen Construction, Earth, Sustainable, Sustainability, Architecture, Affordable Housing

Relevant Websites:

College of Architecture Compressed Earth Block research page Exit

Progress and Final Reports:

Original Abstract

2013 Progress Report

2014

P3 Phase I:

Comparing the Sustainability of a Compressed Earth Block House to a Conventionally Framed House Built to National Green Building Standards  | Final Report