Compared with other European countries, building regulations and building control mechanisms for earth construction in Germany are relatively clear cut. While in other countries, such as in France, there have been cases where new earth buildings have had to be dismantled due to insufficient building control mechanisms in this field of construction, a reliable statutory framework has existed in Germany since the publishing of the Lehmbau Regeln, the German earth building codes (published by the DVL, the German Association for Building with Earth), and their subsequent incorporation into the model building regulations by the DIBt, the German approvals body for construction. This means that since 1998, it is no longer necessary to seek special approval on a case-by-case basis for a range of common applications, which has made the use of earth building materials and techniques for load-bearing and non-load-bearing applications much more straightforward. The DIBt approved the most recent third edition of the Lehmbau Regeln in 2008 with the condition that the DVL should work towards developing DIN norms for industrially manufactured earth building materials.
The first draft norms for selected earth building materials have now been developed based on extensive testing undertaken by Dr. Urs Müller and Dr.-Ing. Christof Ziegert at the BAM Federal Institute for Materials Research and Testing:
- Earth plaster mortars – terminology, building materials, requirements and testing procedures
- Earth masonry mortars – terminology, building materials, requirements and testing procedures
- Earth bricks and blocks – terminology, building materials, requirements and testing procedures.
The authors of the draft norms also elaborated quality control procedures for the basic raw material used for earth building materials in the form of a guideline – “Quality control procedures for earth mixtures used for industrially manufactured earth building products” – which outlines non-mandatory quality guidelines for the material. Rammed earth and earth building boards or clay panels are currently not covered by the draft norms. Earth mixtures mixed on site are unaffected by the norms and are covered, as before, by the Lehmbau Regeln.
The draft norms and guidelines are currently subject to a consultation period, after which the DVL will establish an official norms committee at the DIN. For architects and planners, as well as for end users, the norms will result in a better class of more reliable building materials. While manufacturers will initially be subject to more intensive inspection procedures, official quality approval (the Ü-sign certification for construction materials in Germany) will improve the marketability of their products nationally and internationally.
The next stage will be to incorporate normed earth building materials in the various generally application norms, for example for plastering and masonry. First initiatives have already been undertaken at a national and international level.
The interest shown in the German draft norms by our colleagues in other countries raises hopes that a European norm may be possible in the long term.
