EarthUSA News Issue #4 — Earth USA 2024

IN THIS ISSUE

Intro

Welcome to the Fourth Issue of EarthUSA News
A Photo Essay of New Mexican Adobe Churches

Articles

Cob Research Institute’s Cob Code Approved for the 2021 IRC
CobBauge: An Innovative European Project Seeks to Reduce the Carbon Footprint through Earthen Construction
Encountering and Engaging the Regulatory Building Process in Canada when Utilizing Earthen Materials for Construction
Earth USA 2019 Demonstrates the Importance of Earthen Materials in Architecture and Construction Worldwide

Regular Column: Getting the Dirt On …

Getting the Dirt on ... Quentin Wilson

Timely News and Events

Timely News and Events
Mudtalks! A Podcast Dedicated to All Things Earth Building
Call for Contributions

Welcome to the Fourth Issue of EarthUSA News

Welcome to the fourth issue EarthUSA News, an expanded electronic newsletter on earth building in the United States and beyond. This issue comes out during uncertain, trying, and challenging times due to the worldwide coronavirus (Covid-19) pandemic. We hope that you, your families, friends, and communities are well and our hearts go out to all who have been affected. Please be safe and take care.

EarthUSA News seeks to engage those interested and involved in earthen construction; to preserve and promote its cultural, economic, environmental, historical, and social aspects; and to be a source of both timely news and institutional knowledge.

EarthUSA News further acts as a bridge between the biannual Earth USA conference as well as an outlet to those involved in complimentary fields and the general public.

In this issue of EarthUSA News, there are a number of informative and illuminating articles. Firstly, readers will find a most engaging photo essay on adobe churches in New Mexico with the photographer/writer capturing the breadth and diversity of these traditional churches. Also of interest to readers, we hope, are the two timely articles on building with cob; one highlights the recent inclusion of a cob construction appendix to the International Residential Code while the other discusses an innovative project within the European Union utilizing cob to reduce carbon emissions. Thirdly, we hope that the article on how one might encounter and engage the regulatory process in Canada when planning to use earthen materials in construction might be both revealing and helpful to those in that country and beyond. And fourthly, there is a recap of Earth USA 2019, with this conference demonstrating how earth building continues to be of interest and importance worldwide.

In additional to articles, readers will note that EarthUSA News’ regular column, “Getting the Dirt on …” features Quentin Wilson. Quentin is a tireless advocate who for years has been promoting all things adobe, and had been a colleague, friend, and mentor to so many in this field. We also look into the recent podcast of Mud Talks, a podcast devoted to adobe and earthen construction, produced by Adobe in Action.

Finally, one will find the announcement of two major conferences that are slated to occur in next year: Terra 2021 and Earth USA 2021. Both are scheduled to take place in Santa Fe, NM; Terra 2021 in June, and Earth USA 2021 in September.

We hope that whether you have been reading EarthUSA News since its inception or you are doing so for the first time, you find it of interest and value. We also welcome your written contributions to it as well as your comments. Contributions, comments, and questions can be sent to editor@adobeinaction.org.

Mark Zaineddin
editor, EarthUSA News

A Photo Essay of New Mexican Adobe Churches

Photographs and text by John A. Benigno

My Adobe Church Project is a visual narrative in the great tradition of documentary/fine art photography exemplified in the work of Bernd and Hilla Becher, Edward Weston, Edward Curtis, and William Christenberry. Christenberry’s work is especially important to me. It captures the fragility of the world he observed.

It was Eudora Welty who wrote, “Place is my source of knowledge. It tells me important things.” These artists focused on specific places, and rendered them iconic. Like them, place is the primary theme in my work.

My passion for place developed from my educational background in the social sciences, especially anthropology and history. In New Mexico, there are few places more specific, distinct and unique to place than its adobe churches (especially those still overlaid in the traditional manner with either mud and straw or lime plaster) which are quickly disappearing from the landscape. These “traditional” churches are the focus of my project. They are monuments to the Native American and Hispanic civilizations that first settled New Mexico. They function as the metaphoric spine that binds the people of New Mexico to their religion, rituals, traditions, and culture. For these reasons alone, they should continue to be preserved in the long-established, time-honored ways.

Social, religious, economic, cultural, political, and natural forces all threaten these sacred buildings so deeply rooted in New Mexico’s history. Tragically, too many traditional churches have been replaced, fallen into disrepair, or been plastered over with modern building materials. While the social scientist in me appreciates the cultural alienation that attends modernization, the resulting neglect of these churches signals a growing disconnect between parishioners, their churches and their traditions.

My objective is to photograph and document these endangered churches before they literally melt away, yielding to both natural and social forces.

Three churches, in particular, exemplify what draws me to this project.

First is the Capilla de Santa Rosa de Lima in Santa Rosa. Today, it is in ruins. The community simply outgrew this tiny structure – their spiritual needs are attended to by a large modern church.

The chapel continues to serve as the centerpiece for the local Catholic cemetery, and, in its current state, lends a certain otherworldliness to the timeworn graveyard. I cannot help but wonder if, in the still of night, this tired and frayed sanctuary ever senses its past glory.

Second is the San Francisco de Asís Church in Ranchos de Taos. For economic reasons, several years ago the local residents decided to cover the exterior of their church with stucco. However, they were disappointed with the look of this modern building material. For both historical and cultural reasons, they removed the stucco and replaced it with traditional mud and straw.

Third is the San Rafael Church in La Cueva. When Joe Gurule’s and Gina Pacheco’s father returned from World War II, he gave thanks by taking a sacred vow to maintain the decaying church. Today, only his son, Joe, his daughter, Gina, and her husband, Raymond, remain to carry on. It is a tremendous responsibility, especially considering that, over the years, layer upon layer of mud and straw have stressed the exterior walls. This past year, with the help of Cornerstones Community Partnership, they removed the mud and straw from the exterior walls and replaced it with a new coating.

Adobe needs constant care. Its use speaks to the steadfastness of faith and culture to endure despite the relentless erosion of not only time and environment, but from the pressures caused by the rapid modernization that took place in New Mexico during the 20th Century. This project is dedicated to the volunteers who contribute their time and resources to maintain their community church in the traditional manner. Their unselfish efforts are truly an inspiration.

Photograph fifteen: Nuestra Señora de la Luz IV, Canoñcito at Apache Canyon. Copyright, 2016, John A. Benigno.This is a detail of the cross that fronts Nuestra Señora de la Luz. The adobe church was built in the 1880s, as a mission of St. Anthony of… — *Photograph fifteen:* Nuestra Señora de la Luz IV, Canoñcito at Apache Canyon. Copyright, 2016, John A. Benigno.
This is a detail of the cross that fronts Nuestra Señora de la Luz. The adobe church was built in the 1880s, as a mission of St. Anthony of Padua Parish in Pecos. The church sits only a few feet from I-25, and is threatened by vibrations from the high volume of traffic along this major highway.

John A. Benigno is a Philadelphia-based photographer who has dedicated the past 20 years to project oriented fine art/documentary photography. His work has been exhibited throughout the United States and at the U.S. Embassy in Kuwait as part of the U.S. Department of State's Art in Embassies program. Photographs from the Adobe Church Project have been shown or collected at the Archives of the Palace of the Governors in Santa Fe, NM; the Archdiocese of Santa Fe, NM; the Diocese of Gallup, NM; the Christian Brothers San Miguel Mission Church Archives, in Santa Fe, NM; and the Philip and Muriel Berman Museum of Art at Ursinus College in Collegeville, PA, among other places. Benigno's other projects include Amish Country Landscapes, White Flowers, Details, By the Sea, Laurel Hill Cemetery, Riding the Rails, Philadelphia Scene, and Southwest Landscapes. His work from these projects can be viewed on his website (http://www.photographicimages.us) and Instagram page (www.instagram.com/jabenigno).

Cob Research Institute’s Cob Code Approved for the 2021 IRC

Written by members of the Cob Research Institute

For the first time, a Cob Construction Appendix has been accepted for inclusion in the International Residential Code (IRC). The IRC is a part of the International Code Council's (ICC) model building codes, which form the basis for building codes in 49 of the 50 United States and a number of other countries.

Also known as “monolithic adobe,” cob is an ancient method of earthen construction, used for thousands of years around the world in regions including Britain, Northern Europe, the Middle East, West Africa, China, and the Southwestern United States. A stiff muddy mixture of clay-soil, straw, water and usually sand is placed in layers to create walls that can support a roof with no need for structural posts. When properly designed, constructed, and maintained, cob homes have proven to last many centuries. Embraced as environmentally friendly, non-toxic, low cost, easy to learn, and artistically inspirational, cob construction has undergone a revival in the United States and around the world since the mid-1990’s. However, because there has been no building code for cob, it has been difficult or impossible to obtain permits for cob buildings in most parts of the United States. With the approval of a cob code this will change, creating the possibility for legal cob construction throughout the US and beyond.

What is this New Cob Code?

The new code was developed as a public service by the non-profit Cob Research Institute (CRI), the result of collaboration by dozens of individuals and years of research and testing at several universities and laboratories. The entire code and supporting documents can be found on the CRI website www.cobcode.org. It will be published in August of 2020 as an appendix to the 2021 International Residential Code. The IRC is revised on a triennial cycle, and anyone can submit proposed codes or modifications. In January 2019, CRI submitted a proposed cob code and in May testified in its support before the IRC Committee. The code was initially disapproved by the committee, citing the lack of testing to support the claim of a one-hour fire rating. The CRI team removed the fire rating and re-submitted the proposal in the Public Comment second phase of this code development cycle.

On October 26, 2019, at the IRC Public Comment Hearings in Las Vegas, CRI’s revised proposed code was voted on by ICC voting members in attendance (mainly building and fire officials). The proposal received an overwhelming 93 votes in favor to 6 against, and later garnered the support of at least two-thirds of participating ICC members in an on-line ballot, leading to its official adoption into the 2021 IRC as Appendix U: Cob Construction (Monolithic Adobe).

While the IRC is a model building code with no legal standing of its own, it is used in most of the United States as the basis for building codes for one-and two-family dwellings, townhouses, and accessory structures. It becomes enforceable through adoption by a governmental jurisdiction such as a state, county or city. State and local jurisdictions have their own schedules for revising and adopting building regulations, typically requiring at least another year or two before new codes are adopted. For example, the 2019 California Residential Code, based on the 2018 IRC, went into effect on January 1, 2020. Check with your local building department or the agency that oversees code adoption in your state to find out when changes based on the 2021 IRC will be enacted in your location.

Furthermore, appendices to the IRC are expressly optional; unlike the main body of the code, each appendix must be specifically adopted by a jurisdiction to become a part of its building regulations. The public can influence this process by expressing a need for such a code to their local building department or overseeing state agencies. Other natural building systems, including strawbale and light straw-clay, have undergone the same process, first becoming appendices to the IRC, and then being adopted into state or local building codes. For example, IRC Appendix S: Strawbale Construction was approved as part of the 2015 IRC and has since been adopted by at least six states and nine city or county jurisdictions.

Even before the cob code is adopted for your location, it could still help you get a permit for your cob building project. All building codes contain a provision called Alternative Methods and Materials Request (AMMR), which allows approval of building systems not included in the code if it can be demonstrated to the building official’s satisfaction that the alternative is “at least equivalent of that prescribed.” To date most permitted cob buildings in the US have used this approach, but the process of compiling the evidence needed to support the permit application is often arduous. The publication of Appendix U should go a long way towards reassuring officials that cob buildings can be a safe and reasonable alternative. Even before adoption, Appendix U can be proposed to a local building department for use on a project basis.

How the Code Effort Began

The Cob Research Institute is a non-profit organization started in 2008 with the mission “to make cob legally accessible to all who wish to build with it.” It was founded by Bay Area architect John Fordice, who fell in love with cob after attending a hands-on cob building workshop in 1996. The class was led by by Ianto Evans of the Cob Cottage Company, the first group to reintroduce cob construction to North America in the 20th Century. Frustrated by the difficulty of obtaining legal permission for cob buildings, Fordice passed the hat at a Natural Building Colloquium and raised enough money to file for official non-profit status. He assembled a volunteer Board of Directors and began combing through the international literature on the engineering and regulation of earthen buildings, while outlining the necessary testing and other steps towards approval of a cob code.

In 2013, CRI Board members Massey Burke and Anthony Dente, PE of Verdant Structural Engineers collaborated with engineering faculty and students at the University of San Francisco to determine the physical properties such as compressive strength and modulus of rupture of cob mixes with varying amounts and lengths of straw. This led to a series of other research collaborations. In 2018, CRI worked with Santa Clara University to construct four full-size cob wall panels with varying kinds of internal reinforcement, ranging from straw-only to a rebar grid similar to those used to reinforce concrete walls. The panels were attached to a testing frame that applied force to the tops of the walls in back-and-forth cycles that simulate the effects of earthquakes. The testing of these walls under laboratory conditions, along with other testing, gave civil engineer Dente the data he needed to write the structural sections of Appendix U.

Another key member of CRI’s team is Bay Area architect Martin Hammer. Hammer is a long-time ecological building advocate who has been involved with code-writing efforts for decades. He was the primary author of IRC Appendix R: Light Straw-Clay Construction and IRC Appendix S: Strawbale Construction, among others. His familiarity with the ICC process and personnel, along with that of colleague David Eisenberg, were critical factors in the success of this endeavor. The team also solicited input from over a dozen experienced cob builders, six civil engineers, and four architects, including Graeme North, chair of the committee that developed the seminal New Zealand Standard for Earth Buildings. The New Zealand Standards are among several earthen building codes and standards that also informed Appendix U.

Further Testing is Still Needed

Although the adoption of Appendix U is a major accomplishment for CRI, the group has its future work cut out for it. The team plans to improve the code in future IRC cycles to make it more useful to designers, builders and homeowners in more diverse geological and climatic areas. The highest priorities for continued testing and research include fire resistance, thermal performance, and additional reinforcement options.

The rising frequency and intensity of wildfires that have devastated western states in recent years have brought increasing scrutiny to the fire safety of our homes and communities. Earthen building materials could provide part of the solution. In bushfire-prone Australia, earthen walls have been classified along with masonry and poured concrete as the most fire-resistant building techniques known. Although cob is so fireproof that it is commonly used to build fireplaces and wood-fired ovens, the code approval process requires testing by an approved laboratory in order for a building method to receive a fire-resistance rating. CRI is currently collaborating with Quail Springs of Southern California to procure the testing required to demonstrate a one-hour or greater fire rating, which would allow cob to be used close to property lines (where it could help stop the spread of fires) and as a common wall between residential units.

One of the most significant remaining obstacles to the legal construction of cob is complying with the energy conservation requirements of the IRC (or your state’s energy code). A building’s thermal performance depends on both the mass and thermal resistance (insulation value) of its thermal envelope, in the context of the local climate; energy codes take all of these factors into account. Cob walls have high thermal mass, which is very beneficial in warm climates or seasons, but low thermal resistance, which is especially important in cold climates or seasons. Most energy codes consider a cob wall a “mass wall” like concrete block, brick, or rammed earth, which reduces the requirement for thermal resistance. But even in warm climates, it is difficult for cob walls to comply without adding some type of insulation. For example, California’s energy code requires that an exterior mass wall in Los Angeles have a minimum insulation value of R-8. The cob samples CRI had tested by Intertek Laboratories yielded an R-value of just 0.22 per inch. At that R-value, a cob building in L.A. would need walls 36 inches thick in order to pass the energy code. This is about twice as thick as common cob building practice in North America and could cause structural concerns in high seismic zones.

To address this issue, CRI has begun a project to test both the structural and thermal properties of lower density cob mixes made by substituting lightweight aggregate such as crushed pumice for the sand, and by increasing the straw content. Even these measures will be insufficient in colder regions. A research project called CobBauge, based at the University of Plymouth, England, has been devising ways to insulate cob walls by wrapping them with lighter mixes of clay and natural fibers including hemp and straw. Further research and testing in this arena will be critical to enable cob homes to be built both legally and efficiently across North America and other temperate regions.

The EU-funded CobBauge project aims to develop composite earthen walls with both good insulation and structural qualities.

Another concern is cob’s performance in earthquakes. The IRC divides the United States into Seismic Design Categories (SDC) A through F, based on the likelihood and severity of earthquakes in each locale. Appendix U states that any cob building outside of SDCs A, B and C requires an engineered structural design, typically by a licensed civil engineer. The full-scale testing done with Santa Clara University, along with similar tests in collaboration with California Polytechnic State University, Quail Springs, and Oasis Design, yielded data about the strength of several reinforcement methods that are summarized in tables in the code. The test walls employed a combination of reinforcing strategies which included straw, with and without steel bar and/or steel mesh to strengthen the wall against seismic and wind lateral loads. Other reinforcing combinations, materials and strategies could be tested, including the use of bamboo, fiberglass, basalt fiber and/or plastic mesh and bars, to increase the range of options available to builders and designers. Further testing can also increase our understanding of proper connections between cob walls and foundations and roof assemblies.

Plans to Promote the Cob Code

In addition to further testing, CRI plans to advocate for the adoption of Appendix U by as many building jurisdictions as possible. As evidenced by the ICC vote last October, building officials have shown remarkable enthusiasm for the cob code, presumably motivated by their desire for environmentally responsible and fire-safe building methods. Still, the building regulatory community is understandably conservative, as it is charged with ensuring building safety, and a great deal of education and advocacy will be necessary to bring the code into widespread usage.

CRI also intends to create an educational guide for builders who wish to use the code. Building codes can be challenging to interpret, and many people who are drawn to natural building methods lack experience deciphering the technical language. Towards that end, Hammer and the CRI team are currently writing the official commentary to be published along with Appendix U next year. This commentary will provide useful background information and further details intended to help builders and officials alike understand the intent of the code and how to use it correctly. Appendix U: Cob Construction (Monolithic Adobe) will be an evolving resource for promoting best cob building practices, hopefully encouraging ever greater acceptance of this treasured and time-tested building method.

CRI Needs Your Support

The research, testing, and writing of this Cob Construction Appendix, and its submittal to the ICC for approval has been an expensive undertaking. Although our work has been generously supported through crowdfunding and donations, as well as by enormous amounts of volunteer effort, we still have a substantial debt remaining to paid. In order to continue our work, CRI needs your support. If you recognize the value of building with cob, please go to www.cobcode.org and join with CRI to make cob safe and accessible to everyone.

Thank you,
the CRI Team!

This article was initially drafted by Michael G. Smith and edited by many of the board members of The Cob Research Institute (CRI). It originally appeared on CRI’’s website at: https://www.cobcode.org. CRI is a 501(c)3 non-profit organization founded in 2008 by John Frodice and others whose mission is to make cob legally accessible to all who wish to build with it. CRI is dedicated to three major goals: 1.The scientific study of cob's material properties; 2. The development of standards for safe cob construction which can be easily understood by builders and officials alike and which retain cob’s character as an environmentally sound, user-friendly building technique; and 3. The development and widespread adoption in North America of a building code for cob.

CobBauge: An Innovative European Project Seeks to Reduce the Carbon Footprint through Earthen Construction

Written by the CobBauge Team

A unique partnership in earth building is currently taking place in Europe; one which has resulted in a project called CobBauge. CobBauge — a play on the English and French words for cob construction — is a project that is part of the European Union’s efforts to reduce carbon emissions by twenty percent in the French and English Channel (FCE) area by 2020 (2012/27/EU).

CobBauge is a two-phased project focused on constructing low-carbon buildings. It makes use of cob, a centuries-old earth-building technique, to accomplish this. Constructing low-carbon structures is important as energy consumption in the building sector currently represents 40 percent of the total energy produced (UE2010). 60 percent of this is used by occupants to heat buildings.

Why cob and earthen construction? Well, anecdotally, many ancient building techniques have provided householders with properties that are cool in summer and warm in winter while using little fuel to heat or cool them. Additionally, less embodied energy is needed in this construction. Knowing this, it is therefore logical to look to vernacular buildings such as those constructed from the earth to potentially provide future solutions for new housing. The cob houses that are the focus of this project are commonly found in the Channel Regions of France and Great Britain, some of which date back over 400 years.

*CobBauge incorporates an innovative twin-layer composite wall*

Yet, today, thermal and energy regulations in residential and commercial construction can be stringent and these vernacular forms of architecture have been unable to conform to the required standards (United Kingdom [Part L], and France [RT2012]) in this region. So how does this project address such regulation? That is, how can one make use of earthen materials and the advantages of constructing with cob while at the same time allowing homebuilders, architects, engineers, and contractors to legitimately meet regulatory standards?
CobBauge does this through a unique wall design. Phase one of the project generated the concept of a twin-layer composite wall; one structural layer is an optimized version of traditional cob, while a second light layer of earth and fiber provides the insulation required to meet above mentioned UK and French building regulations. This first phase was competed in December 2019.

*The CobBauge team in front of a prototype wall.*

A second phase is now underway. This phase will incorporate the new CobBauge walls into two full-scale buildings and will continue through to June 2023. During this time, the new buildings will be both occupied and monitored for energy use, indoor thermal conditions, and indoor air quality. Results will be then compared with equivalent, conventionally constructed buildings. But it is not just the completed buildings that will be evaluated; the construction process and energy usage during construction will also be assessed. Currently, researchers are seeking clients to construct pilot buildings in the United Kingdom and France where the CobBauge walls can be applied and monitored in practice.

This innovative project is the recent recipient of the EU RegioStar’s award in the sustainability category. Details and highlights of the project were presented at Earth USA 2019, an international conference on earthen construction which took place in Santa Fe, New Mexico in October 2019.

CobBauge is supported by INTERREG VA France (Channel) England and involves six partners in France and the United Kingdom. Project partners are Plymouth University; Ecole Supérieure d’Ingénieurs des Travaux de la Construction de Caen (ESITC Caen); Parc naturel régional des Marais du Cotentin et du Bessin (PnrMCB); Earth Building UK and Ireland (EBUKI); Caen Normandy University – LUSAC Laboratory; and Hudson Architects (HA).

More information on the CobBauge project and technical methods can be found on the project website, http://www.cobbauge.eu/en/.

Encountering and Engaging the Regulatory Building Process in Canada when Utilizing Earthen Materials for Construction

Written by Tim Krahn, P.Eng., LEED TM AP. Building Alternatives, Inc.

Authorities having jurisdiction in Canada are currently in their third code cycle since the introduction of an objective-based national model code. The first National Building Code of Canada (NBCC) to adopt an objective-based format was issued in 2005. The Canadian Commission on Building and Fire Codes attempts to re-issue an updated version of the major model codes (Building, Fire, Plumbing, and Electrical) every five years. The current national model building code is the 2015 edition, with a 2020 edition on pace to be issued late in 2020 or early 2021.

The move to an objective-based code did not eliminate the listing of prescriptive solutions for a given building assembly, rather it involved adding alternative regulatory paths to acceptable solutions. By defining the goals of the code via cross-referenced objective and functional statements, the objective-based format attempts to give designers and code officials methods to evaluate a potential design for conformance apart from a ‘cookbook’ approach. Specifically, an alternative solutions proposal protocol was first introduced into the 2005 NBCC. However, differences in the way that each province and territory adopts the model code into their legislation, compounded with differences in the way any given municipality enforces their regional code and/or modifies it via local by-laws, leave designers and project proponents with a range of conditions to deal with when applying for a permit to build.

Before the adoption of the objective-based model code, non-conforming materials and designs were permitted on a project by project basis, either via the building official’s discretion, via some type of approved research program, or because of exceptional circumstances. An example of the building official’s discretion is given in the first case study below. An approved research program is most often a case where a municipality and an academic institution co-operate to demonstrate a novel building technique that is funded publicly. Exceptional circumstances are really an extreme case of this; for instance, an Olympic village or World’s Fair site. It is not the purpose of this paper to deal with projects of that magnitude per se; rather, the example is given because those projects are also designed, permitted, insured, funded and ultimately constructed – simply at a scale much higher than most residential builds.

Both before and after the advent of the objective-based code model, a key element to winning the building official’s approval directly or via a research program is the establishment of material qualities that can be measured and shown to be consistent with the design methodology adopted by the engineer or architect. This is a primary challenge for the designer; choosing an accepted design methodology developed for a similar, yet different, material and then developing a test method to prove that the different material behaves sufficiently like the accepted one to justify the analysis and final design. Two examples are given in the case studies, one following the Canadian concrete design manual and the other the Canadian masonry design manual. Engineering design standards and their accompanying manuals, guides, and commentaries are published by the Canadian Standards Association (CSA).

Similar to the ICC-ES system in the United States, the Canadian Construction Materials Centre (CCMC) is responsible for evaluation and national certification of innovative building materials, products, and systems. Conventionally, a material or product attains CCMC certification in order to be widely accepted by designers, regulators, and builders. All CCMC certifications are referenced in the NBCC by default; thereby, allowing relatively easy specification and acceptance. At some point in the future, the material or product may be cited directly in the body of the building code itself. Polystyrene Insulated Concrete Forms (ICFs) are an example of a product or system that has gone from CCMC evaluation to outright specification in the national code within the past 20 years.

The variability in aggregate content, mix recipe, and method inherent in working with natural or pre-industrial materials and techniques such as Stabilized Rammed Earth (SRE) effectively precludes evaluation by a body like the CCMC. It should also be noted that the evaluation process is lengthy and expensive, and, to date, there have not been any proponents of earthen construction in Canada willing to attempt it.

This leads to each project being evaluated on its own merits, which raises another challenge. Before the issuing of a permit, inspection criteria must be determined along with a quality control and materials testing program to be carried out during construction. A requirement for any project varying from common construction techniques or materials is a “Commitment to General Reviews” by the design professionals. This is a basic form establishing the party or parties responsible for inspections and site reviews, but it does not include a great amount of detail and is often accompanied by a document clearly stating the agreed upon schedule, notable milestones, and substantial completion criteria. Two different pre-construction testing programs and two different construction phase inspection protocols are given in the case studies.

Two Case Studies

Extra-urban residence – Huntsville, Ontario
The Allen residence, located just outside of the town of Huntsville, in the Muskoka region of Ontario, was completed in the fall of 2012. It was the first SRE single-family dwelling to apply for a building permit in the region. The preconstruction materials testing program for this project was initiated in the spring of 2010.

The town of Huntsville has a Development Services branch, which includes their Building and Planning Departments, along with By-Law enforcement and Sustainability. As of 2013, the Building Department did not employ any registered professional engineers for plan examination or inspection.

The design methodology for the engineering of the SRE walls on the Allen residence was a hybrid of the Canadian Concrete Design standard CSA A23.3 (Canadian Standards Association, in press) and various techniques and analysis tools taken from the international literature. Of primary concern was the effect of freeze-thaw cycles on exposed SRE walls in a Canadian climate. Pre-construction testing included evaluating different grain size distributions in the source soil mix, varying Portland cement content, the addition of a silicon emulsion ad-mixture for permeability reduction (Plasti-cure by Tech Dry), and oxides for color control. The structural design was controlled in large part by the compressive strength of the test samples. 150mm diameter x 300mm tall test cylinders were tested at 28 and 56 day curing times. The durability of the different mixes was tested by exposing block style samples to the environment and by creating excessive freezethaw cycles during the winter months.

For durability, a minimum Portland cement content of 5% by weight, plus the manufacturer’s recommended dosage of admixture to reduce permeability was determined to be adequate. For structural stability, a minimum of 7.5% Portland cement by weight was determined to be necessary to achieve a 15 MPa design compressive strength. The testing program was summarized in a simple document and presented to the building officials in Huntsville along with the completed drawings set at the time of permit application. The building official requested an in-person meeting with the structural engineer in order to discuss the material and building technique, and was satisfied within 15 minutes; provided that the engineer take on responsibility for inspecting the SRE walls and assume full liability for their performance.

Follow-up testing involving samples taken during construction was requested, but occupancy was not denied before the test results were submitted after construction was completed.

Urban residence – Ottawa, Ontario
The Smyth-Allcott residence is a two story single family dwelling built just south of Ottawa, Ontario in the suburban community of Kemptville. The building has single story SRE walls with light wood frame second story walls above. The conceptual design was taken to the city of Ottawa’s building department for an initial consultation by the client and architect in April of 2012. At that point in time, a zoning official looked over the proposed design and told the owner and architect that they did not see any outstanding issues that would prevent or delay a building permit being issued.

Following a similar pre-construction testing program to the one employed for the Allen residence, the design was completed over the winter and spring of 2012/13. The city of Ottawa is in an active seismic zone, and the appropriate lateral load capacity of the structural walls is required to be shown in any engineering design submitted for permit.

The city of Ottawa has a Planning and Growth Management Department, employing several registered professional engineers and architects in the Building Code Services division. In the case of the Smyth-Allcott permit application, a technician in the residential plan examination division reviewed the plans and then passed them up to an engineer in the commercial division. The technician did not feel qualified to review the plans, as the structure included materials and techniques outside of part 9, the prescriptive core of the Ontario Building Code (OBC), similar to the IRC in the US model national code.

The structural engineer reviewing the set of plans and calculations was not familiar with earthen construction methods, nor with SRE as a material that could be designed using engineering principles. As a result, the engineer requested evidence via testing done in a Canadian context to prove that SRE could reliably be designed in general accordance with CSA A23.3.

Notwithstanding the lack of published research on SRE from Canada, two larger concerns were raised regarding the use of the concrete design standard for this different material. First, the minimum compressive strength for reinforced concrete is currently set at 25 MPa. Second, the CSA A23.1 and A23.2 standards set limits to the quantity of particles of less than 80 µm diameter present in a given sample of aggregate. The inability of SRE to meet these two qualities effectively ruled out the use of the concrete design standard for engineering analysis in this case.

Supporting documents submitted with the initial permit application included the New Zealand Engineering Design of Earth Buildings, which is written in concert with both masonry and concrete design methodologies for reinforced and un-reinforced assemblies alike. Reference to this standard prompted a re-design carried out in general accordance with the CSA S304.1 standard, Design of Masonry Structures. The minimum compressive strength for reinforced masonry under seismic loading in CSA S304.1 is 15 MPa, and the standard contains no minimum aggregate size criteria, as masonry containing clay - both fired and chemically stabilized - are permitted.

The primary change to the engineering analysis resulting from the shift to a masonry-based standard from a concrete one was the increased importance in slenderness ratio as opposed to reinforcement in driving the final design.

In terms of the permit application process, the fastest path forward was determined to be an alternative solution application asserting the equivalence of the reinforced SRE to a reinforced masonry wall.

Conclusions and Recommendations

It is common to encounter varying interpretations of building code requirements between different jurisdictions. It is also common to find that a jurisdiction with a larger population will have more rigorous plan examination and inspection requirements than a neighboring jurisdiction with a smaller population. In large part, this is due to higher staffing capacity and experience with a broader variety of projects in the more populous region. However, the resulting inconsistency in the application and enforcement of federal and provincial codes at the municipal level effectively creates separate classes of construction regulation where no such separation is intended, or even allowed.

A recommendation is for regulators to set a minimum level of adjudication necessary for an alternative solution proposal to be considered. This may involve third party professionals in some jurisdictions, but this is not unprecedented for plan examinations or inspections that are outside the expertise of the staff in any given building department.

Correspondingly, designers must educate themselves about what regulators need to see in order to move a permit forward when an unfamiliar material or building technique is being proposed. The challenge lies in working together without blurring lines of liability and client responsibility. At the same time, the opportunity exists to work together to create clear and consistent design and administrative guides that lead to a better built environment.

This article was first presented as a paper at the 1st International Conference on Rammed Earth Construction in Perth & Margaret River, Western Australia, February 10-13, 2015. That paper has been published in the conference proceedings, printed by CRC Press, Edited by Ciancio & Beckett, 2015. ISBN: 978-1-138-027701

Tim Krahn is a licensed engineer with degrees in the civil and geotechnical disciplines. His professional interests include natural building materials, integrated design and education, energy and infrastructure sustainability, and a healthy built environment. He is a LEED accredited professional and heads up Building Alternatives Inc.’s Ontario office. He is the author of the book, Essential Rammed Earth Construction: The Complete Step by Step Guide, published by New Society Publishers.

Earth USA 2019 Demonstrates the Importance of Earthen Materials in Architecture and Construction Worldwide

Written by Kurt Gardella, Adobe in Action

Earth USA 2019 conference attendees in front of the Scottish Rite Center, Santa Fe, NM

Earth USA 2019, the 10th International Conference on Architecture and Construction with Earthen Materials, took place from Friday, October 25th to Sunday, October 27th, 2019, at the Scottish Rite Center's Alhambra Theater in Santa Fe, New Mexico. The conference was organized by Adobe in Action.

More than 150 earth building enthusiasts attended the conference to view 32 podium presentations, 20 poster presentations, and two demonstration sessions. Walking and bus tours of significant and vernacular adobe structures followed the conclusion of the conference.

Presenters converged on Santa Fe from around the world including countries such as Bangladesh, Brazil, Canada, Chile, China, Egypt, India, Japan, Mexico, Norway, Rwanda, Spain, and the United Kingdom. The United States also had strong representation with presenters and attendees from California, Colorado, New Mexico, Oklahoma, Pennsylvania, South Carolina, Texas, Utah, and Virginia.

Fred Webster Memorial Prize winner Jun Mu (second from left) with Fred Druc, Brendan O’Connor Webster, and Quentin Wilson

Prof. Ronald Rael (Acting Chair of Architecture and the Eva Li Memorial Chair in Architecture at the University of California, Berkeley) dazzled attendees with his keynote presentation entitled "Mud Frontiers: Notes from the Borderlands”. Also of note was the inaugural Fred Webster Earth Building Engineering Prize. This was awarded to the presentation "From 'Why to do' to 'How to do': Research and Practice in Rammed-earth Architecture in China" by Professors Jun Mu, Tiegang Zhou, and Wei Jiang all of the Beijing University of Civil Engineering and Architecture, China.

Paperback copies of the Earth USA 2019 Conference Proceedings can still be ordered at a special discounted price here.

Full details about past, present, and future conferences can be found at www.earthusa.org.

Regular Column: Getting the Dirt on ... Quentin Wilson

Quentin Wilson has spent a career in the field of adobe in New Mexico and is a vociferous proponent of building with the earth. As this column suggests, he became interested in adobe as a youngster. In addition to constructing adobe homes, he started and oversaw the adobe program at Northern New Mexico College, and has been a principal instigator, facilitator, and promoter of the Earth USA conference, a biannual conference in the United States that brings scholars, practitioners, and others from all over the world to discuss and share their earth building undertakings and interests. Practicing what he preaches, Quentin and his wife Maria continue to live in the same adobe home which have resided in for fifty years.

How did you first get interested or involved in earth building?

At age ten in the fifth grade, I was highly influenced by two barefoot men who led a horse around between the Armijo Ditch and Sunset Road in Albuquerque’s South Valley to mix mud to make adobe bricks. When my teacher assigned us the job of making house models there was no choice for me but to make miniature adobe bricks on a cookie sheet and bake them in my mother’s oven. The rest, as they say, was houses, forts, banks and churches.
Where do find your passion in this field? For example, are you particularly interested in the architectural, community building, cultural, economic, engineering, environmental, regulatory, or sociological aspects of earth building?

Right now, I just love living our adobe home of fifty years. Maria and I raised three children here and in the past two years we finished projects, started new ones, and renovated, renewed, replaced, replicated, modernized, conserved energy, shored up, activated, celebrated, and worked toward a space for aging in place. The house is largely passive solar and I relish walking through in the morning opening up to the sun and walking through at nightfall closing apertures. This would be a nice place to die in if I live that long.
Since you started the adobe program at Northern New Mexico College, what changes within the field of earthen construction have you witnessed? Where do you see important contributions coming from in the future or likewise where do you see earth building going?

All the important structural imperatives were known and in use in Biblical times and probably the Shang Dynasty in China: a good foundation, sturdy lintels, a bond beam and a good roof. Further developments are mostly aesthetic and convenience items.

The number of earthen homes being built yearly in New Mexico remains at low level. We hit bottom in 2013 – which is how long the 2008 downturn took to hit New Mexico. That year ten adobe homes at most were built in the State. We have improved but are far from the fifty to sixty homes built in the banner years around 2000. We are seeing very few commercial or other large buildings being built.

Beacons of hope come along. In 2010 for the 40th anniversary of the Smithsonian Magazine came the list “Forty things you need to know about the next forty years.” Number One was: “Sophisticated Buildings Will Be Made Of Mud,” according to MIT professor John Ochsendorf. Ten of those years are gone so we need to accelerate our work. Keynote speaker at Earth USA 2019, Ronald Rael, showed us four small but habitable buildings that he 3D printed in Colorado with materials sourced from within a hundred feet. Italians have a beautiful tripod machine that builds earthen buildings and students at Indiana University are working to get a large drone to place twenty-pound blobs of mud to create walls in the manner of a mud dauber - call it monolithic or cob. Personally, I strongly favor the methods of simple labor. Besides buildings, the world needs jobs.

It is comforting to know that besides the ten Earth USA conferences there are other earth building-related conferences around the world every year. Young people are paying attention.
What have been the highlights of you career? What you currently working on?

Starting in 1976, I spent twenty-five years building adobe homes in Northern New Mexico as a licensed general contractor. Those were certainly formative years for me and I relished each of the twenty modest, affordable houses I built. The smallest was 1000 square feet for the man who built New Mexico’s tallest building and the largest was 2700 square feet for the director of Ghost Ranch.

My career capstone is the fifteen years 1995 to 2010 developing and teaching The Adobe Program at Northern New Mexico College in El Rito. The real highlight is seeing students go out and form careers in construction, teaching, community building, design and architecture. For example, Mike Lopach established Adobe in Action in Santa Fe, NM, and now, Brick by Brick in Scottsdale, AZ; Kirk Higbee has created the world’s largest bibliography on earth building subjects, got a BS in Engineering so he can defend adobe, and is the treasurer of Adobe in Action; and Kurt Gardella developed the teaching of foundation to roof earth building skills over the Internet and is a certified earthen plasterer by the Dachverband Lehm of Germany all while being a major organizer of Earth USA Conferences.
Why is it important that the general public become more educated about earth building?

John Ochsendorf goes on to say it nicely: actually, very sophisticated buildings of masonry were constructed for five thousand years. Then in the past decades the romance of titanium and other high-tech materials have led the public’s image of what sophistication means. Gone are the arches, domes, vaults, buttresses that made such buildings as the sixth century Hagia Sophia in Istanbul stands with a sixty-meter high dome. The world needs to appreciate the sophisticated simplicity of masonry and the simplicity of its sophistication. The public needs to know that earth building is legitimate, well understood, mainstream, and prolific across the globe and time. It isn’t quaint, cute mud huts that wash away in the first rain; it’s powerful structures that stand up to weather, human foibles, and time.
What else would you like to share with the earth building community or the general public about yourself or the field?

After each brick goes into the wall, grab another.

Timely News and Events

UPCOMING ACTIVITIES AND EVENTS

Please find below upcoming activities and events. While seeking to promote earth building activities and events, EarthUSA News cannot vet or verify all activities and events, or the entities that are organizing them. As always, please contact the entity with any questions or concerns that you may have.

Adobe in Action 2020 Online Earth Building Courses

In spite of the current Covid-19 crisis, Adobe in Action’s activities have continued uninterrupted due to the online delivery format that the organization has been using since 2012. Adobe in Action's next online class - Foundations for Adobe Structures - begins on May 11th. This is a great class to begin the program with since every successful adobe project begins with a sound foundation. More info about this class (as well as our summer/fall 2020 online classes) can be found at https://www.adobeinaction.org/event-calender/.

More information on the courses, registration, and the certificate program can be found at www.adobeinaction.org/certificate-classes/.

Adobe in Action is a New Mexico-based 501c3 non-profit organization which supports owner builders with the planning and construction of adobe homes; promotes adobe home building and ownership through education and student-based field support; produces Mud Talks, a podcast dedicated to earthen construction; and organizes Earth USA, the largest biannual conference on earth building in the United States.

Conferences

Two important earth building conferences will be held in Santa Fe, New Mexico, next year — Terra 2021 and Earth USA 2021. Both organizers are monitoring the Covid-19 pandemic very closely and the challenges it presents. Please check the website of each respective conference for updates as well as for deadlines.

Terra 2021 to be Held in Santa Fe, NM in early June 2021
Terra 2021, the 13th World Congress on Earthen Architectural Heritage, is slated to take place June 8th - 11th, 2021, in Santa Fe, NM, at the Santa Fe Community Convention Center. It will be the second time the conference has been held in New Mexico since the conference was inaugurated in 1972. Terra 2021 is expected to draw hundreds of specialists from a wide variety of fields from all over the world. Pre-congress workshops and post-congress tours will also be available.

The conference, held under the aegis of the International Council on Monuments and Sites, International Scientific Committee on the Conservation of the Earthen Architectural Heritage, is being organized by the Getty Conservation Institute, the National Park Service Vanishing Treasures Program, and the University of Pennsylvania School of Design.

For more information, please visit www.terra2021.org.

Earth USA 2021 coming to Santa Fe, NM, in late September 2021
Earth USA 2021, the 11th International Conference on Architecture & Construction with Earthen Materials, will be held from September 24 to 26, 2021 at the Scottish Rite Center's Alhambra Theater in Santa Fe, New Mexico. It is organized by Adobe in Action.

This biennial conference will include diverse podium presentations and poster sessions which feature adobe, rammed earth, compressed earth block (CEB), and monolithic adobe (cob). It will be of interest to academicians, architects, practitioners, those involved in various aspects of public policy, as well as the general public. The call for abstracts will be opening in September 2020.

Full details about past, present and future conferences can always be found at www.earthusa.org.

Paperback copies of the Earth USA 2019 conference proceedings can still be ordered at a special discounted price here.

Mudtalks! A Podcast Dedicated to All Things Earth Building

Mud Talks – created by Adobe in Action (AinA), a non-profit organization based in Santa Fe, NM – is a worthwhile and highly informative podcast devoted to adobe and earthen construction.

As of this issue, nine episodes have been produced by Kurt Gardella, Education Coordinator and Instructor of AinA, and feature Quentin Wilson, director emeritus of Northern New Mexico College's Adobe Construction Program and currently President of AinA.

In the ninth Mud Talks podcast, Quentin Wilson takes us through the basics of finishing adobe structures with interior and exterior plasters.

The series will be now shifting to a series of guest interviews with other experts from the field.

The Mud Talks podcast can be listened to at www.adobeinaction.org/mud-talks/, iTunes, and other favorite sites where one downloads podcasts.

Call for Contributions

A Call for Submissions to EarthUSA News

EarthUSA News very much welcomes your contributions. EarthUSA News promotes earth building architecture and construction as well as its cultural, economic, environmental, historical, and social aspects. The target audience of EarthUSA News is not only those directly and indirectly involved in the field but also the general public.

Submissions can include articles, timely news, book reviews, and upcoming events or activities. They should be clearly and concisely written. Photos are also welcome. We reserve the right to edit, postpone, or reject submissions based on relevancy or other matters. We regret that at this point we cannot pay for such submissions. For more information on contributing, please do not hesitate to contact the editor at editor@adobeinaction.org.