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Cave-Like Monolith Crafted from Black Sand and Glacial Water

Authors:
Pablo Castro, Louis Boulacheb
Cave-Like Monolith Crafted from Black Sand and Glacial Water
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Crafted from black sand and glacial water, the monolithic structure embodies a cave-like form that offers visitors an immersive experience while engaging with the surrounding Icelandic landscape.
5 key facts about this project
01
Crafted using 75% black sand, emphasizing sustainability and local materials.
02
Features a vertical cavity design that mimics natural cave formations.
03
Integrates rainwater collection for sustainable water management.
04
Includes an observation deck that provides 360-degree views of the landscape.
05
Facilitates unique sensory experiences through steam and heat within the cave-like structure.

The project sits in a valley, responding to the area’s natural features and elemental characteristics. It is designed as a monolithic structure that integrates with its surroundings, encouraging curiosity and exploration. The overall concept focuses on a vertical cavity that reflects the attributes of a cave, offering both immersive experiences and connections to the geological components of the site.

Design Concept

At the heart of the design is a form that takes inspiration from simple shapes present in the local environment. This choice enhances the relationship between the building and the landscape. The monolith allows for both enclosed spaces and wide views, creating a balance between privacy and openness that resonates with visitors.

Visitor Experience

The journey to the structure is carefully planned. Visitors start from a designated parking area and make their way to a small visitor center. From there, they ascend towards an observation deck, encountering viewpoints along the way that showcase the surrounding landscape. This thoughtful pathway deepens the connection between visitors and their environment, preparing them for the experiences within the cave-like space.

Material Composition

Construction comprises specific materials: 75% black sand, 15% cement, and 10% water sourced from Icelandic glaciers. This mixture underscores a commitment to sustainability and ensures low maintenance for the structure. Utilizing local materials strengthens the project's ties to the geology of the area, reflecting the natural landscape it inhabits.

Spatial Dynamics

Inside, the design emphasizes interactions with fundamental elements like water, steam, and rock. The spatial arrangement creates various sensory experiences that engage visitors. As they descend into the cave, they feel the heat, encounter steam, and experience the unique moisture present in this geological setting. This design choice invites individuals to connect more deeply with the architecture and landscape surrounding them.

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The Next House: USA — A Global Call to Reimagine the American Suburb

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Competition organisers

Buildner is launching The Next House: USA, a global architecture competition that challenges architects, designers, and thinkers to reimagine the American suburban home for the 21st century. For decades, the suburban house has symbolized comfort and stability, but today it often reflects excess, isolation, and environmental strain. This competition asks: how can the American home evolve to address climate urgency, economic pressures, and shifting social values?

Participants are tasked with designing a prototype home of no more than 1,500 sq ft (≈140 m²) for a household of two adults and one child. The design should be compact yet generous, adaptable, sustainable, affordable, and replicable across diverse U.S. contexts. More than a design exercise, the competition aims to spark a conversation about how homes can support healthier, smarter, and more connected communities.

The total prize fund is $20,000 USD. The final registration deadline is May 20, 2026, and winners will be announced on September 22, 2026. The Next House: USA invites architects, students, and visionaries worldwide to redefine what the American home means today—and what it should mean tomorrow.

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