37 Construction and repair of buildings, roads, bridges, dams and electrical transmission lines; installation and maintenance of road signs; construction, installation and maintenance of structural devices, expansion joints, support devices, antiseismic retensions for roads, bridges and building constructions; installation and maintenance of vehicle containment devices and road barriers; construction, installation and maintenance of prefabricated concrete buildings; construction and maintenance of waste disposal plants; construction, maintenance and installation of electrical systems for power generation and destruction plants; installation and maintenance of electrical control panels and computer systems; installation and maintenance of telephone lines and high-frequency telephone systems; construction of metal- framed buildings; construction, maintenance and installation of telecommunication and data processing networks and related equipment; soil consolidation namely, soil erosion control services; construction, restructuring, installation and maintenance of potabilization and water purification plants; construction, renovation and maintenance of industrial or civil buildings; restoration of real estate in the nature of building restoration services; construction and maintenance civil engineering structures, including roads, highways, bridges, aqueducts, gas pipelines, oil pipelines, agricultural irrigation systems and wastewater removal works; waterproofing of buildings; construction and maintenance of river works, namely, dams, weirs and levees; construction, renovation and repair of plants for the production and transformation of electricity; installation and maintenance of heating, ventilation and air conditioning systems; installation and maintenance of electrical systems, telephone systems, radio transmission facilities, and television broadcast towers; maintenance services for real estate property; construction of residential buildings; demolition services, namely, buildings, roads, highways, bridges, aqueducts, gas pipelines, oil pipelines, dams, leeves; construction, installation and maintenance of conveyor and lifting systems, elevators and escalators; installation and maintenance of pneumatic conveyor systems in factories; installation and maintenance of anti-intrusion systems; installation of coating and insulation materials to the buildings; masonry; painting services, namely, application of protective paint on walls; house painting; installation of building insulation; installation and maintenance of noise and fire barriers; construction and maintenance of railways and associated structures; construction, installation and maintenance of factories for manufacturing neon signs; construction and maintenance of ports and structures for maritime areas, specifically, lighthouses; installation of safety equipment