Earth House by Lara Fuster Prieto: A Sustainable Adobe Home in Rural Spain

Located in the small municipality of Boadilla de Rioseco, Spain, Earth House by Lara Fuster Prieto is an architectural response to the depopulated landscapes of rural Spain. This eco-friendly home integrates traditional adobe construction, passive design principles, and contemporary living standards, all while minimizing its environmental impact.

Reviving Adobe Architecture for Modern Living

The house is built in Tierra de Campos, a vast treeless plain in the Castilian-Leonese plateau, known for its extreme and dry climate. Traditional vernacular architecture in the region relies on adobe bricks—a sustainable material made from earth and straw, abundant in the area. Adobe construction has minimal carbon footprint, as the material is locally sourced, requires no firing, and is fully biodegradable. The design of Earth House embraces these principles while adapting them to contemporary construction methods.

Sustainable Design and Passive Strategies

Designed as a permanently inhabited residence, Earth House prioritizes thermal comfort and energy efficiency. Its rectangular structure consists of four parallel bays oriented from east to west, optimizing sunlight exposure. The north façade, which faces the street, has smaller asymmetrical openings, reminiscent of traditional local houses, while the south façade features large windows to function as solar collectors in winter. During summer, wooden blinds and a pergola with deciduous vines provide natural shading, reducing overheating.

The load-bearing walls are constructed from 33x15x10 cm adobe bricks, produced within 40 km of the site. These walls are insulated externally using cork panels, creating an External Thermal Insulation Composite System (ETICS) that enhances energy efficiency. The gable roof consists of a wooden sandwich panel with cork insulation, topped with reused curved clay tiles, seamlessly blending into the local urban fabric.

Natural and Breathable Materials

Instead of conventional cement, the house uses lime mortar mixed with straw for plastering, a breathable and moisture-absorbing material that ensures durability and sustainability. Wooden doors and windows contribute to the home's low-carbon footprint, while roll-up shutters act as passive sun protectors.

The interior partitions follow a lightweight construction system, featuring exposed wooden slats, recycled cotton insulation, and Medium Density (MD) wood boards. To maximize natural light, the upper sections of these partitions incorporate polycarbonate sheets, creating a sense of openness.

Energy Efficiency and Thermal Performance

By leveraging the thermal mass of adobe, the house maintains stable indoor temperatures between 22-24°C during peak summer, even as outdoor temperatures reach 40.5°C. The home achieves A-rated energy performance, requiring no active cooling systems.

During winter, the house employs underfloor heating, inspired by the glorias—a traditional underground heating system from the region. This design ensures that the home remains comfortable year-round while consuming minimal energy.

Blending Tradition with Sustainability

More than just a sustainable home, Earth House is a cultural and environmental statement. It bridges the gap between traditional Spanish adobe construction and modern sustainable architecture, proving that heritage materials can play a crucial role in low-impact contemporary design.

All Photographer are works of Milena Villalba