The building required deep, solid foundations, which were laid on reinforced concrete pillars embedded into the rock bed at an average depth of 14 meters. As many as 665 of these piles were driven, as the building is situated on clay substrate from the bottom of the nearby Bilbao River estuary.
The base of the building is covered with beige limestone from the Huéscar quarries near Granada. The walls of the building have been specially treated against the sun, and the window glass has been treated so that sunlight will not damage the exposed elements.
