At the end of the 1960s, Severin Ahlmann also produced prefabricated garages and, above all, developed drainage systems made of the new material polymer concrete. This brings the final breakthrough in the 1970s. National expansion is followed by international involvement. Severin Ahlmann, who traveled a lot both privately and professionally, was always on the lookout for worthwhile investments on his travels around the world. Especially in the 1970s.
It was during this time that he founded the ACO plants in Switzerland, France and the USA.
ACO Andernach was sold in 1974 and the entrepreneurial focus shifted to the Rendsburg and Reith sites as well as the production of polymer concrete products in his new foreign plants.