Building a Sustainable Dream

Building with Earth, Straw, and Recycled Materials

The Aardehuizen are inspired by architect Michael Reynolds’ Earthships. In the United States, he built his Earthships using what the world considered “trash”—from car tires to glass bottles and cans. He also made extensive use of natural materials available in the area. Architect Michel Post of Orio Architects adapted these principles to Dutch conditions, such as our precipitation, temperature, and soil. The scarcity of building land in the Netherlands also influenced the design: blocks of 2, 3, and 4 homes instead of all detached (more expensive) houses. 

Whenever possible, we built using reused, local, and natural materials. Old car tires, compacted earth, wood, straw, loam, and lime were all incorporated into the homes.

The houses are oriented toward the sun and feature a glass south-facing facade. The solid north wall, thick floors, and heavy interior walls provide thermal mass. As a result, an Earth House stays cooler in the summer and warmer in the winter than a conventional house. The earthen slope at the rear of the house and the green roof provide insulation, a green appearance, and greater biodiversity. The roofs have a 9-degree pitch to make optimal use of the sun’s rays.

Step by step, a building concept emerged that is visibly different from that of a conventional home, and our Dutch Earth Houses became more and more authentic.

A Construction Site for Learning

Building it ourselves was a conscious choice. We learned as we built—from the construction coordinators, from the tradespeople, and from each other. Nearly two thousand volunteers from the Netherlands and abroad also pitched in. They came to contribute to this special project, but also to learn about earth house construction, straw bale construction, helophyte filters, and clay masonry. 

At the same time, they brought their own experiences and skills to the table. And they also brought their own personalities, unique stories, and cultures.

That’s how the construction site became a place where knowledge was shared. And in the evenings, around the campfire, volunteers shared colorful stories from all over the world.

From Car Tires to Straw Bales 

The first block of houses was completed in May 2013, a year later than planned. With this unplanned delay, it quickly became clear that we would have to reorganize the construction process to pick up the pace. So we sat down together again to see what adjustments we could make to make our dream a reality. 

Specialized teams were formed for tasks including roofs, facades, overlapping timber cladding, masonry, logistics, and engineering. We also established our own (non-profit) contracting company and hired additional skilled workers for specific tasks. We also became more selective in accepting construction volunteers. Those who could come to help build for longer periods or more frequently were given priority.

At the same time, we had to make a number of decisions that significantly affected our construction pace. For example, in the last eleven homes, the car-tire rear walls were replaced with a timber-frame structure filled with straw bales. A few low domes were omitted, rammed-earth partition walls were henceforth constructed using sand-lime brick, and from that point on, the homes were delivered as shell-only structures. Each household therefore had to arrange the interior finishing work on its own. For those whose homes were still very much under construction, this was quite a major adjustment. But we kept building steadily, in good spirits. 

What do those two construction methods look like?

Those changes were not only visible internally but are still visible in our neighborhood. Twelve homes have a load-bearing wall made of old car tires, filled with compacted earth, behind a green earthen embankment. The other eleven homes have straw walls. On the inside, these homes are equipped with an extra-thick clay wall to provide a temperature-buffering effect, similar to that of the solid tire walls in the other homes.