The “Terranova” render of the Engineering Faculty in Bologna (1931–1935): reasons for an outstanding durability

In the first half of the twentieth century, a variety of dry-mix renders with different trade marks spread across Europe. Their stated performance made them attractive for buildings where the overhanging eave was absent, hence they found broad application in rationalist buildings and districts. However, their composition and properties are barely known. In this paper, the Terranova render of the Engineering Faculty in Bologna was characterised, to investigate the reasons for its outstanding durability. Unexpectedly, the render was found to be constituted by dolomitic lime and only a small amount of white cement and exhibited a remarkable strength. The presence of air voids seems due the use of air entraining agents and may have contributed to the frost resistance of this render during 80 years. The results are expected to contribute not only to the knowledge of Terranova render, but also to a better understanding of durability issues for new renders.