Rocksplit House: local stone “kotounto” construction aids with heat dissipation

Cometa Architects’ Rocksplit house utilizes traditional stone cladding methods to regulate thermal exchange, keeping the building cool.

The steep ground and the plot’s narrow dimensions determine the pronounced form of the building which rises from the mountain and over the valley of Poisses, ultimately balancing itself with the surrounding traditional dwellings and natural context.

This second home of a family of four spreads over three levels which clearly can be defined respectively as the seating & kitchen level, circulation tower, and the sleeping & storage level. The principal material chosen is local stone, which has been carefully crafted against the horizontal micro-cement surfaces.

The experience offered by the Cycladic landscape is the main concern of the building’s design, expressed through the spatial evolution and relationship of the building with the dramatic land. This is achieved through a traditional method of construction called “kotounto”: a dry, humidity-free space between the rock and the building. The external space – a continuous perimetrical “kotounto” – gives the impression that the building is trying, at times, to break away from the rock and, at others, to reconcile with it.

Apart from this traditional technique of which is principally used to drain the waters coming from the mountains, leaving walls and foundations dry, the 50cm-thick envelope walls are made out solid rocks (30cm), eco-insulation (5cm), and local bricks. The dry-masonry method of building the wall makes it totally transpirable and it multiplies the surface. Therefore, its heat dissipation creates an air current within the wall. The eco-insulation and the whitewashed brick walls allow the building to breathe.

The house includes in its design an under-floor heating system which powered by the solar panels installed on the roof. Conversely, cooling is achieved from cross ventilation and also an additional under-floor cooling. Finally, the rainwater is collected in the 3 rooftops and stored in an underground reservoir.