Currently, load-bearing earth masonry is only standardised and approved using general earth mortar with approx. 12mm joint thickness. With the thin-layer mortar processing, considerable time savings can be achieved in wall construction and, thanks to the simple, manual processing, even unskilled labour can build walls. This results in considerable cost savings and rationalisation of the construction process. In past research and in the design standard for load-bearing earth masonry DIN 18940 published in 2024, however, only load-bearing earth masonry with general earth mortar has been researched to date. In conventional masonry construction, a construction method that accounts for 70% of new residential construction in Germany (Federal Statistical Office, 2022), the thin-layer mortar method has clearly prevailed for economic reasons. In order for earth masonry to become competitive with conventional masonry, standardisation of the thin-layer mortar method for earth masonry is of great importance.

The aim of this GOLEHM research project is to create the constructive, static and normative basis for the planning and dimensioning of load-bearing earth masonry using the thin-layer mortar method by building owners, architects and civil engineers. To this end, the load-bearing behaviour of load-bearing earth masonry with earth thin-layer mortar is to be researched on the basis of extensive experimental, numerical and analytical investigations by the Institute of Solid Structures at TU Darmstadt.

The basic principles for the design of unstabilised earth masonry with earth thin-layer mortar are developed as follows: Following a comprehensive market analysis, representative earth thin-layer mortars and earth blocks are selected that cover the range of earth building materials on the market. The relevant material strengths and stiffnesses are determined by experimental tests. Subsequent tests on masonry test specimens under vertical loads and shear loads provide information on the block-mortar interactions, the masonry strengths, stiffnesses and corresponding bearing loads. The data is consolidated by developing a numerical model that realistically depicts the non-linear material and load-bearing behaviour and by carrying out a parameter study. Finally, based on the experimental and numerical data and taking into account sufficient reliability in accordance with Eurocode 0, a structural design concept for load-bearing earth masonry with thin-layer earth mortar will be developed and finally validated. Based on the research results obtained, a normative design proposal for earth masonry with earth thin-layer mortar is to be developed, which is compatible with DIN 18940 and can be incorporated into its next revision.