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Natural Building

The Art of Natural Plasters Workshop
Clay & Lime Finishes
July 2nd-7th 2023


"A proper building grows naturally, logically, and poetically out of all its conditions."

- Louis H Sullivan

The Art of Natural Plasters workshop is an immersive learning experience that focuses on the use of traditional and natural materials to create beautiful, durable and sustainable finishes for walls and other surfaces. During the workshop, participants will learn about the various types of clay and lime plasters and finishes, the techniques for applying them, and the benefits of using natural materials in building and design. These techniques are well-suited to natural wall systems such as straw bale and cob, but are equally appropriate over conventional materials such as drywall.

Hands-on experience is a key component of the workshop. Approximately six hours each day will be spent mixing and applying plaster to a real natural home, allowing participants to develop application skills while plastering on different substrates and experimenting with various finishing techniques and textures. Lectures and discussions will cover the health benefits of natural finishes, how to select the most appropriate plaster type for your situation, the importance of proper surface preparation, what tools you will need, how to source the best ingredients and develop and test your own plaster recipes, how to calculate the amount of materials you will need, how to maintain and repair natural plasters, and how to design your home to minimize maintenance over time. 

This workshop will cover a wide range of natural wall finishes including:

  • Straw-clay base coat plasters ideal for protecting straw bales and for sculptural relief work

  • Lime scratch, brown and finish coats for wet and weather-exposed surfaces

  • Smoothed and polished clay finishes suitable for all interior walls

  • Lime-clay combinations

  • Sgraffito – the art of carving through multiple layers of different plasters to create a textured and multi-colored design

  • Simple, durable clay paints you can make yourself

  • Tadelakt – a highly polished and waterproof lime plaster from Morrocco


At the end of the workshop, participants will leave with a deeper understanding of natural plaster and finish techniques and the confidence to apply these techniques in their own projects. 

In addition to the practical skills and knowledge gained during the workshop, participants will also benefit from the opportunity to connect with a diversity of people and learn from experienced instructors in a supportive and collaborative environment. 


For more information about the daily flow of learning, check out the syllabus below.

Meet the Instructors

Michael G. Smith

Michael has taught hundreds of hands-on workshops ranging from one-day earthen oven workshops to three-month professional trainings, and has designed or built close to 100 natural-building projects using many different techniques, including cob, straw bale, straw-clay, wattle-and-daub, rice-crete, earthen floors, natural plasters, and many more. He helped start the Cob Cottage Company in 1993 and the Natural Building Colloquium in 1994. He is co-author of “The Hand-Sculpted House” (Chelsea Green, 2002), “The Art of Natural Building” (New Society, 2015), and the forthcoming “Essential Cob Construction” (New Society, 2024). As a founding director of the Cob Research Institute, he was instrumental in writing the first model building code for cob. Energy efficiency, passive solar design, empowerment of people through simple, accessible techniques, and the regenerative use of locally available materials are always the focus of his work. 

For more information, check out Michael's website


Athena Steen

Athena Steen was one of the pioneers of the straw bale revival, building her first straw bale home at the age of 19. In 1989, with her husband Bill, she founded The Canelo Project, a center for natural building and cultural revival in southern Arizona. Together they have developed many innovations in straw and clay construction, ranging from simple straw bale pinning techniques to high-fiber “light adobes” to a revival of poured adobe floors. They emphasize everyone’s capacity to house themselves beautifully and inexpensively, using local natural materials and innate wisdom. They have worked extensively on low-income housing projects in Mexico and traveled and taught all over the world. Athena and Bill have also written half a dozen books, including “The Straw Bale House” (Chelsea Green, 1994). Well known for her artistry with natural finishes, Athena has collaborated on art museum installations at the Smithsonian’s National Museum of the American Indian in Washington D.C., and several other museums.

For more information, check out Athena and her families' website,


Robert Kolden

Since the early 1990’s, Robert has worked extensively with Milestone and Venetian Plasters, as well as his own custom mixes. He has worked in the construction field for over 30 years and attended School of the Art Institute of Chicago with a focus in Ceramics. Robert’s expert construction experience paired with his artistic background reflects his business' (Kolden Specialty Finishes') commitment to creating durable and long lasting finishes that are visually enticing and artistically applied. 

View more about Robert's work on his website,



Avani Leitz

Avani began her journey in natural building in the beginning of 2017, building a cob cottage with her partner from the ground up. Since then she has delved into all types of structures including straw bale, pallet buildings, light clay straw and more. Guided by her desire to use materials that are local, salvaged, recycled and respectfully wild harvested, she utilizes back to the hands techniques to create functional and beautiful structures of art. 



Join us in the Okanogan Highlands  

Tonasket, WA

“Tirth”, which means “place of pilgrimage” in Sanskrit, is a beautiful 120 acre wildlife refuge and home located in the Okanogan HIghlands, around 3200 feet in elevation, in a land of timbered forests, canyons, mountain lakes and meadows.  Along the creek that runs through the middle of the land, a series of beaver ponds have created a vibrant wetland habitat, and during any season, one can observe almost all the wildlife, flora and fauna native to this unique area of Washington State.  Over the years, people have lived, worked, played and gathered at Tirth, attracted to its quiet, joyful, and peaceful energy.  The land has hosted small music festivals, several healing gatherings, and two barter faires.  The Tirth family and friends are excited to make preparations and welcome you to this fun and unique workshop opportunity — to work together, forge new friendships, soak up the magic of the highlands, and learn the skills of natural building.  

Camping on-site & all meals included!

Registration Information

Enrollment is limited so please register early. 50% deposit required to reserve your spot. The remaining balance is due upon arrival.

Workshop Cost: $1,200

DISCOUNTS (30% off max): 

  • EARLY BIRD Discount 10% off: Pay in full by May 17th

  • Family and Friends discount 10% off: Register together and each person gets a discount

  • BIPOC price 20% off:  We acknowledge that many techniques of earthen building have been learned and adapted from cultures around the world that have been marginalized and even destroyed. May this be a way to include people who have been systemically isolated from ancestral knowledge and hereditary wealth.

  • Partial work trade for partial enrollment discount is available (please inquire)

Cancellation & COVID Policy



If the workshop is canceled for any reason, you will be refunded any money you have paid towards the workshop. If you choose to withdraw from the workshop, refunds are available only for sincere health/life related reasons until June 25th.  After this date, partial refunds can be discussed on a case by case basis.



We honor freedom of choice and do not require individuals to be vaccinated to participate in the workshop.  Thankfully the majority of the workshop will be outdoors so time spent indoors with others will be very minimal.  In general, we will be following the recommendations and requirements of the CDC and Washington State during the workshop.   We will send any relevant updates/ reminders about COVID protocols a week before the workshop.


We recommend that you try to reduce your exposure to COVID for a couple of weeks prior to the workshop whether or not you are vaccinated. We want everyone who comes to the workshops to feel safe and to feel that we are taking adequate precautions to greatly reduce the risk of anyone bringing COVID here or spreading it while here.

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