COB OVEN + ADOBE THERMAL MASS HEATER | INTENSIVE | GRÂNDOLA, PORTUGAL

Join us for a theoretical and hands-on workshop focusing on earthen building through the techniques of cob and adobe. In this 10-day intensive workshop, we will build a complete cob oven with a built-in grill and working table, as well as a full adobe mass heater inside an ongoing Earthship project.

In this certified workshop, you’ll learn how to analyze and stabilize clay-soil mixtures for earthen building, exploring the principles of adobe and cob as building techniques. Through this hands-on experience, you will build a full cob oven—from foundations to finish plasters—and a thermal mass heater, from preparing the adobe bricks all the way to completion.

The aim is to equip students with the knowledge and tools to test and analyze clay soils, and to understand each step involved in building a cob oven and a thermal mass heater. We will have 70% hands-on practice and 30% theoretical learning, diving into different natural building techniques, everything about cob ovens, stone-foundation principles, the benefits of earthen building, how to prepare and apply earthen plasters, how to sculpt with cob, and much more!

Once the workshop is completed, you will have the skills to build your own cob oven and/or thermal mass heater, and you will also be able to begin building your own earthen walls for your projects.

Join us for this intensive experience and become part of the TIERRAMIGO community, gaining access to the community chat to connect with others, learn about additional trainings with discounts, and get the Earthen Hands book for a special price!

What is a cob oven?

It is a traditional oven built with a mixture of clay, sand, straw, and water. Its operation is based on the retention and gradual release of heat by its thick earthen walls. These ovens are known for their high heat-retention efficiency, reaching very high temperatures, where the heat cooks food through three physical mechanisms: radiation – heat from the fire and the hot walls toward the food, convection – hot air circulating inside the oven, and conduction – the direct transfer of heat from the hot surface to the food (the oven floor).

Thus, these ovens are capable of gradually retaining heat for hours, making them very practical and versatile for cooking different foods: from instant pizzas to stews, meats, vegetables, and even—at the end, using the residual heat—for fermenting yogurt, dehydrating foods, and proofing bread.

Cob is a very inclusive, organic, and creative earth-building technique that allows us to shape walls freely, working with curves very easily. In this way, we can sculpt around the oven and its bench, turning it into a collective work of art.

What is an adobe thermal mass heater? 

The principle behind this stove is thermal mass: since it is built with adobe bricks, they are able to store the heat from combustion and retain it for a longer time, gradually releasing it into the environment.

The stove features double combustion, making the burning of firewood more efficient and making better use of the resource. Secondary combustion allows for cleaner burning and better utilization of the wood. This is achieved by introducing more air in a second stage. It enables a more efficient use of the fuel, minimizing the toxic effects generated by burning wood.