Glass was becoming a construction material in its own right with the growth of architecture combining steel and glass for large public edifices such as railway stations, exhibition centres, greenhouses, indoor food markets, covered walkways and department stores.

The twentieth century was a century of diversification. Saint-Gobain became interested in all types of glass products and took advantage of the considerable growth of the automotive market and contemporary architecture. The merger with Pont-à-Mousson in 1970 marked a turning point in the history of the Group, deeply transformed by the strong trend toward mergers and acquisitions.