Architecture on Volcanic Ground: From Réunion to Iceland

At 2,240 meters above sea level on Réunion Island, a single compact lodge houses up to 100 visitors to the national park around Piton de la Fournaise — and it must generate most of its own energy and water to do so. That project, Gîte du Volcan by Altitude 80 Architecture and Atelier Épicéa, replaces a group of older structures and anchors a newly published ArchDaily collection examining what happens when volcanic conditions dictate where buildings sit and how they take shape.

Volcanic landscapes make geological change unusually visible. Lava hardens into new ground. Plants slowly take hold across it. Ash can persist for years. Around active volcanoes these processes are still underway, and people keep building there anyway, drawn by isolation and terrain far removed from urban life.

Designing with the landscape

At Gîte du Volcan, three curved volumes follow the site and reference the corded basaltic lava flows of Piton de la Fournaise. Solar panels supply electricity and hot water, and rainwater is collected in reservoirs beneath the building. Weathering steel covers parts of the exterior; locally sourced cryptomeria runs throughout.

A different relationship between building and volcano appears in Japan. Tree Hut on Volcano by Hiroshi Nakamura & NAP is a 19-square-meter structure about two kilometers from Owakudani, a volcanic valley where sulfuric gases rise from the ground. Hydrogen sulfide and moisture concentrate near the surface, so the architects raised the hut roughly five meters above the slope. The height opens views toward Mt. Kamiyama and Owakudani and separates the interior from nearby streets.

The mountain has shaped local culture for millennia. An eruption at Mt. Kamiyama around 3,000 years ago helped form Owakudani and Lake Ashi, and communities have long held goshinka-sai, a holy fire festival meant to appease the mountain. Inside the hut, a central fireplace dedicates fire to Owakudani and Mt. Kamiyama.

Planning around the volcano

A volcano does not need to sit beneath a building to shape it. Volcano House by Pilar Beltrán + Br-Arquitectos, near Puerto Varas in southern Chile, stands close to the Calbuco and Osorno volcanoes. The design begins with axes drawn from the site toward their summits. Those lines set the orientation of the house, turn its main spaces northeast, and work with sunlight and the gentle slope of the site. The main living area sits where the two wings meet; bedrooms extend outward from there.

That orientation points toward an active mountain. Calbuco erupted in April 2015, two years before the house's reported completion.

Building on volcanic ground

Some projects stand directly on ground formed by past eruptions. Lavaflow 7 by Craig Steely Architecture occupies a 1955 lava flow on the slopes of Kīlauea in Hawai'i, where ʻōhiʻa trees — among the first trees to take root on new lava — have gradually turned bare rock back into forest. The house sits inside that recovering forest as a long, narrow volume. A single concrete beam runs along much of its length, allowing wide glass openings and covered outdoor spaces to face the trees. Because the plan is thin, every room looks out to forest, sky, or coastline. The eruption and the regrowth both happened within the last century, and both remain visible from inside.

Volcanic ground can also enter a building as material. At Lava House by Paul Weiner | DesignBuild Collaborative in Arizona, the walls contain crushed cinder quarried from the San Francisco volcanic fields in northern Arizona, mixed with a small amount of cement and cast into thick walls that form most of the enclosure. Once the forms come off, workers lightly sandblast the walls to expose the aggregate. Their mass and texture give the interior a more enclosed relationship with the desert. The house is also placed to keep nearby roads, power lines and neighbors out of view — volcanic material quarried in northern Arizona becomes part of a house in the Tucson Mountains, much farther south.

Tracing volcanic activity over time

At Stöng, in Iceland's Þjórsárdalur valley, volcanic activity is bound up with how the past is read. The remains of a Viking-era farmstead were excavated in 1939 and sheltered in 1957. For decades, researchers tied the abandonment of settlements in the valley to Hekla's 1104 eruption, which spread ash across the area. Later studies of the ash layers complicated that account, finding evidence of human activity for two centuries after 1104, with land use changing again after another eruption around 1300. When and why Stöng itself was abandoned remains debated.

SP(R)INT Studio's 2024 intervention adds another layer. The existing shelter is kept and extended. A translucent roof covers the remains, a raised platform lets visitors move above them, and openings connect the ruins back to the valley while the enclosure protects them from weather and volcanic ash.

Across these projects, the volcano appears at different distances from the building: on the horizon, orienting a house; underfoot, as lava forming the ground plane; inside the walls, as crushed cinder. Those same conditions explain the draw. Retreating into volcanic terrain means living with visible evidence that the ground has changed before — and may change again.