Abstract: A modular unit (1) of customizable color for creating load-bearing structures, photovoltaic houses, for use as a construction and/or a support for photovoltaic carpets (7). Namely, this support or modular base unit, made of extruded plastic, can act as a floor, roof, and/or lateral panel/support; furthermore, this module may be also used as a support for a photovoltaic carpet mounted thereto; thus, the photovoltaic carpet can be mounted to a plastic support instead of the usual metal support or bitumen sheets, as is typically used. This allows one-time application of the photovoltaic carpet (7), even without a thermoplastic load-bearing or containing support, by simply laying it to existing rigid surfaces over the desired areas (B8), and ensuring chemical bonding at the lateral ends, with water tightness guaranteed over time.