TRADITIONAL KILNS EVERYWHERE

Image 1. Footprint of a traditional kiln in Domusnova (Sardinia)

It's been a long time without writing. That does not mean that I have continued traveling, discovering and learning everywhere.
As I am preparing a presentation for the APT 2013 conference regarding the traditional gypsum I am now more aware of the old methods of obtaining gypsum or lime (similar procedure different times of burning). I am finding old footprints even in the most unexpected places. During my recent trip to Sardinia I found a traditional kiln in
an excursion for rock climbing in the small town of Domusnova. As it is seen in the picture, the kiln was half-excavated in the slope of the mountain to keep the heat . Usually the diameter was around 2 meters. A dome was built with the gypsum/lime stones, then a fire was set and usually the times of burning will depend of the material: usually 1 day for gypsum [1].

Image 2

Honestly this is amazing, everywhere you could build a traditional kiln. They were usually, and logically, built close to the quarry or close to the building site where was going to be used. Now they are not in use anymore in lieu of new products that you can easily buy. However, in Spain there is one factory that still "cooks" the gypsum as the traditional manner (http://www.yesoalbarracin.com). Their properties to weathering are higher than new gypsum because of several factors (procedure, heterogeneity, ...)
In this website you will find some pictures of kilns and the typical sequence of the whole process to create the gypsum mortar:
http://alfredosanchezgarzon.blogspot.com/2011/10/visita-guiada-los-hornos-de-yeso-de-la.html

Image 3. Footprint of a traditional kiln in Domusnova (Sardinia)

References:

[1] F.Vegas, C.Mileto, M. Diodato, J. Garcia Soriano, C. Grau Giménez: “Traditional Structures Made with Gypsum Pillars: A reasoned Hypothesis” in: Nuts & Bolts of Construction History, Vol. 2. Paris (2012) pp 509-516.

[2] D. Sanz Arauz in: “Análisis del yeso empleado en revestimientos exteriores mediante técnicas geológicas”, tesis doctoral, Universidad Politécnica de Madrid, Escuela Técnica Superior de Arquitectura, Departamento de Construcción y Tecnología Arquitectónicas, Madrid (2009)