Precast building block, modular element with optimized geometry, process for obtaining the modular element, construction, method for obtaining a building by assembling the modular elements

A precast block for construction, comprising:

• an upper area;
• a lower area comprising a lower interior face;
• an interior face configured to come in contact with another interior face of a second precast block, the interior face comprising the lower interior face;
• an exterior face;
• and
• two lateral faces,
• wherein the interior face comprises:
• at least one main open vertical channel that opens at the lower interior face, and
• at least one secondary open channel that starts from one of the two lateral faces and extends to an intersection with the at least one main vertical channel,
• wherein at least one of the two lateral faces comprises assembling elements for joining with a third precast block, and
• wherein the exterior face comprises:
• one or more recessed areas;
• and
• a plurality of protrusions from the one or more recessed areas, each of the plurality of protrusions following a profile of the at least one main open vertical channel and the at least one secondary open channel on the interior face, respectively, to provide a uniform thickness of a precast block wall, and the plurality of protrusions comprising fastening areas for veneering elements formed by ribs set on the protrusions.