This innovative course in the rainforest of Costa Rica provides students with a unique opportunity to explore the design/build process using earth, straw, cob, stone, site-milled wood, bamboo, and recycled/reused materials. The class will stay at the Rancho Mastatal Environmental Learning Center and work on a community library project in the village of Mastatal.Students will have the chance to collaborate on a variety of design assignments. The class will survey and discuss different building techniques and work hands-on and in-depth with a featured number of them. The class is ideal for architecture, environmental studies, and building technology students and professionals as well as those interested in incorporating natural building techniques into their own projects. Food and lodging at Rancho Mastatal is included in the tuition cost. Visit for more information on the class location.

For additional information click here.

  • Competency Level: All Levels
  • AIA credits: 84

The Location

Rancho Mastatal, an environmental learning and sustainable living center, retreat and lodge located in the last virgin rainforest of Costa Rica's Puriscal County, practices and promotes living responsibly in the tropics, while educating its visitors about the significance and majesty of the world's disappearing tropical forests. The site encompasses 300+ acres of picture-perfect waterfalls, crystal-clear rivers, and impressive trees in the transition zone between very wet and pre-montane rainforest in one of Costa Rica's most undiscovered regions. The property shares a significant border with the splendid La Cangreja Reserve, a protected area providing habitat for a number of endangered animals and flora, and containing some 2,500 plant species and varied fauna such as 2-toed sloths, trogons, scarlet macaws, boa constrictors, toucans, poison-dart frogs, blue morpho butterflies, motmots, white-faced capuchin monkeys, coyotes, and anteaters. Rancho Mastatal maintains 13-kilometers of rainforest trails, connecting to a network of footpaths in La Cangreja.

The hospitable and attractive agricultural community of Mastatal sets this area aside from others in the country, and provides the visitor with a glimpse of "tico" campesino life. The locals invariably spawn the fondest memories for those taking the time to interact with them and are what truly make this corner of Central America a special and exceptional destination for conscientious visitors.

On site and in the community, at Rancho Mastatal they build using natural techniques and local materials, including bamboo and cob, and support the use of renewable energy systems. As part of Rancho Mastatal's ongoing commitment to education and instruction, they organize and sponsor a wide array of workshops ranging from alternative design and construction to Wilderness First Responder Certification, and work with schools in both the United States and Costa Rica in offering customized educational programs on rainforest ecology, Latin culture, and Spanish and English as a second language.

Project and Schedule:

This will be our 10th year teaching the Natural Building course at Rancho Mastatal.  The 2012 course will focus on an ongoing community library project in the center of Mastatal (pop. ~ 150).  The library, known as the Community Learning and Sharing Center (CLSC), is designed to provide a multi-dimensional shared space for meetings, events, workshops, and creative exploration.  It is being constructed with local labor and materials in conjunction with the Mastate Charitable Foundation (MCF, more information at  The facility itself comprises a renovated structure, a timber frame addition, and a composting toilet (built by last year’s class).  Construction is ongoing, though there will be multiple opportunities for students to get involved, including but not limited to the following: 

Walls:  These will be a combination of wood framing and siding, wattle and daub, and earthen plaster.   

Furniture:  The class may work on tables, chairs and bookshelves for the interior space of the library.

Design:  There could be design opportunities for the interior layout of the library.

Landscaping:  There are opportunities to landscape with native and edible species both behind and in front of the library.

Cob:  There will be two cob walls that connect the renovated structure to the timber frame addition.   

Limewash:  We can limewash the composting toilet structure that last year's group worked on.

Course Outline

  • Breakfast starting around 7:00 am (coffee, tea, bread, yogurt, fruit, etc)
  • Morning check-in to establish plan for the day
  • Morning work session on site
  • Lunch
  • Free time (hikes to the nearby waterfalls and swimming hole-about 10 minutes away-are highly encouraged!)
  • Afternoon work session on site
  • End-of-day check-in to evaluate progress and plan for the next day
  • Free time between 5-7pm (take a shower, a nap, help make dinner.)
  • Dinner
  • After-dinner project planning, slide shows, or free time

In addition to the daily schedule, a variety of field trips will include visits to see a recent residential project built by Rancho Mastatal, local waterfalls and rainforest, and other points of interest. A list of optional activities for free time is available on the RM website ( ).

While the specifics of the daily schedule will depend on the design/build projects and the interests and skills of the students, the course will be an intensive introduction to the design/build process, with a focus on designing in harmony with the environment, using natural building materials. Topics covered will include:

  • the collaborative design process
  • basic hand and power tool use
  • building with cob (a mixture of sand, straw, clay and water)
  • bamboo construction
  • stone masonry

For additional information click here.

Suggested Reading

John Connell. Homing Instinct Using Your lifestyle to design and build your home

Jack Sobon. Build a Classic Timberframed House

Paul Lacinski and Michael Bergeron. Serious Strawbale

Michael Smith. The cobbers Companion

Becky Bee. The Cob Builders Handbook

Paul Graham McHenry, Jr. Adobe and Rammed Earth Buidlings

Clarke Snell.  The Good House Book

Daniel D. Chiras. The Natural House - A complete Guide to Healthy, Energy Efficient Environmental Homes

Kennedy, Smith, Wanek. The Art of Natural Building

Tim Reith and Bob Ferris. Natural Building Constructing Communities through Cooperation

Lloyd Kahn. Shelter

Francis DK Ching. Buidling Construction Illustrated

Carol Crews. Clay Culture: Plasters Paints and Preservation

Adam WEismann and Katy Bryce.  Using Natural Finishes Lime & Earth-based Plasters, Renders and Paints