While the manufacturing industry in Europe is looking at Industry 4.0 approaches and technologies to maintain the current competitive advantage, on the other hand, in the building industry (BI) they may push an improvement of the overall productivity also. This paper presents a research activity, which has aimed at investigating potentials and criticisms of Parametric and Generative Design techniques in mass-production environments of the BI though a pilot-case-study analysis in Glued-Laminated-Timber (GLT) industry. Starting from programming a parametric algorithm for GLT engineering, the research has measured manufacturing effectiveness and manufacturing efficiency through a Value-Stream Map of an ordinary supply-chain system of GLT. Considering all the limits of referring to a single case study, results highlight improvements both in manufacturing effectiveness and manufacturing efficiency; but limitations have to be considered as well, due to the complete absence of Industry 4.0 approaches and technologies in an ordinary supply-chain system of GLT. •Application of Parametric and Generative Design techniques in mass production environments of the Building Industry•Development of a pilot case study in the Glued-Laminated-Timber (GLT) Industry•Analysis of impacts implementing a parametric algorithm in an ordinary value-chain system of GLT•Testing the effectiveness of a parametric algorithm for product design and engineering through Value-Stream Modelling•The paper highlights needs of Industry 4.0 approaches and technologies in order to overcome actual limitations