After the Decree of 11 March 1941, which limited the use of steel, until the approval of the MV-101/1962 standard on “Actions in Building”, which repealed the previous limitations, the use of iron in building was restricted, giving rise to the corresponding regulation detailing the prescriptions in this respect during the design and execution of the work. (BOE nº 214, 2-8-1941). These regulations were based on prescribing technical solutions that would help to save iron, explicitly prohibiting its use in construction elements that could be built with other materials. In the rest of the constructive elements, the project design was urged to make the greatest savings in iron.
This affected the structural typologies, leaving aside the evolution made in previous years in the use of metal structures, frequently employed until 1936 (Lahuerta, 1965), as well as the construction of high-rise buildings. Therefore, with regard to vertical structural systems, during the entire period of the restriction, practically coinciding with the predominance of RENFE as a developer of housing for its employees, the ceramic brick load-bearing wall, without any quality control of the manufacturing process, was the structural system almost exclusively used as part of the misnamed “traditional construction” (Azpilicueta & Araujo, 2012).