Earth building mortars and other earth building materials have for a long time suffered from a lack of binding norms. In 1997, the German Association for Building with Earth (DVL) published the “Lehmbau Regeln” which established a regulatory framework for building in practice. Those building codes applied predominantly to earth building materials that were produced on site. In the years that followed industrial production methods became more and more widespread.
The DVL recognised early on the need for building regulations and made this a key area of focus for the association. The latest step in this direction is the founding of a Norms Committee at the German Institute for Standardisation, the DIN. The committee was inaugurated on the 23 September 2011 with the aim of agreeing product norms for earth blocks as well as earth masonry mortars and earth plaster mortars. The committee consists of earth building manufacturers, representatives from the DVL, university professors and building control authorities. Further members include representatives of other Associations and users of earth building materials. Dr. Christof Ziegert was elected chairman, Ulrich Röhlen vice chairman of the committee.
Two sets of DIN numbers have been reserved for the earth building norms currently in development or in planning for the future: 18945-50 and 18958-59. The first of these to be allocated are DIN 18945 (earth blocks), DIN 18946 (earth masonry mortar) and DIN 18946 (earth plaster mortar). The current numbering scheme is fortuitous in that it makes direct reference to the old earth building norms from the early 1950s which bore the number DIN 18951.
The DVL can build on work already undertaken. As part of a three-year project undertaken together with the Federal Institute for Materials Research and Testing (BAM) text drafts were developed that correspond to the criteria of norms. Building material testing procedures were examined, modified and in some cases developed from scratch. For example, it should now be possible to asses the often variable water resistance of earth blocks according to objective criteria. For earth plaster mortars further characteristics such as abrasion resistance and vapour sorption capacity have been proposed alongside the typical strength tests. Special attention has been given to determining values for CO2 equivalents, which makes it possible to illustrate the environmental qualities of earth building materials more clearly.
The new earth building product norms are an important milestone on the path to establishing earth as a modern building material. The DVL is also involved in parallel initiatives such as membership of the Committee for Norms on Plastering Works and participation in the respective GEAB committee for developing specifications for plastering works. Ulrich Röhlen represents the association in both committees.
