The volcanic foundation of Dutch architecture:
Use of Rhenish tuff and trass in the Netherlands in the past two millennia

T.G. Nijland ¹, R.P.J. van Hees ^{1, 2}

¹ TNO, PO Box 49, 2600 AA Delft, the Netherlands
² Faculty of Architecture, Delft University of Technology, Delft, the Netherlands

Occasionally, a profound but distant connection between volcano and culture exists. This is the case between the volcanic Eifel region in Germany and historic construction in the Netherlands, with the river Rhine as physical and enabling connection. Volcanic tuff from the Eifel comprises a significant amount of the building mass in Dutch built heritage. Tuffs from the Laacher See volcano have been imported and used during Roman occupation (hence called Römer tuff). It was the dominant dimension stone when construction in stone revived from the 10^th century onwards, becoming the visual mark of Romanesque architecture in the Netherlands. Römer tuff gradually disappeared from the market from the 12^th century onwards. Early 15^th century, Weiberner tuff from the Riedener caldera, was introduced for fine sculptures and cladding; it disappears from use in about a century. Late 19^th century, this tuff is reintroduced, both for restoration and for new buildings. In this period, Ettringer tuff, also from the Riedener caldera, is introduced for the first time. Ground Römer tuff (Rhenish trass) was used as a pozzolanic addition to lime mortars, enabling the hydraulic engineering works in masonry that facilitated life and economics in the Dutch delta for centuries.

Key words: Tuff, trass, Eifel, the Netherlands, natural stone