This paper discusses the impact of the First World War on the daily life of different Portuguese classes of building craftsmen and labour organizations. During a transition period in building cultures, the war disrupted imports of coal, steel laminated products and Portland cement, and the supply of basic goods to the country’s entire population. Strikes, sabotage and violent demonstrations against the war, including by construction worker trade unions, were interspersed with campaigns for better working conditions that began prior to the outbreak of war. O Construtor, the fortnightly newspaper of the Lisbon federation of construction workers, enables us to address the following research questions: how did this working class group fight for better living and working conditions? Did they question construction processes and workplace safety? How did these workers organize themselves for protests? The work concludes with an analysis of how the 1914–8 war influenced the construction industry in Portugal.