Making sarooj
Question: I would like to know how sarooj was mined and the baking process, what was added (crushed shells? gravel? binding agents?) and how sarooj production varied over time.
Answer:
It has taken me quite a while to trace some information in English.
I found it ultimately in a book by Maria Biancifiori, written in Italian originally. She finished the book in dedication to her brother Giuseppe, who worked on the restoration of Omani monuments from 1985 until he died in 1991. The title of the book is 'Works of Architectural Restoration in Oman.'
It is now out of print and only comes on to the second hand market rarely. You could try looking for it at www.abebooks.com although theoretically, you ought to be able to contact the Ministry of (National) Heritage and Culture for the information. I do not know whether the ministry would have the information available in English.
This extract comes from page 24 of the chapter on Materials and Techniques. The writer noted that it had been essential to speak to older members of the community who were the only ones who remembered the technique.
"The Ministry of National Heritage and Culture in Oman took care of the production of about 50% of the sarooj necessary for the projects described.
The raw material is the clayey earth taken from a date palm plantation, usually not far from the site of the building to be restored; in fact, the use of local earth is necessary in order to obtain in the restoration a structure and colour as similar as possible to the original.
This salt-free earth is mixed with water and made into flat cakes.
'Making sarooj is quite a procedure, but one which everyone enjoys - almost like children making mud pies.'
The cakes are put in the sun to dry and then carefully stacked, separated by wadi pebbles, on an enormous, carefully constructed pyre of date palm trunks. The whole structure is then covered with earth to form an airtight seal and the pyre is lit. The firing process lasts about a week. When the fire has died down, the mound is left for a few days to cool. The external layer of earth is then removed and all the residue, including the ashes, is ground to a powder which, when mixed with water, becomes sarooj.
When dry, sarooj takes on various tones of yellow ochre according to the zone of production.
Chemically, sarooj is similar to a hydraulic cement."
Sarooj with higher silicate content is a much better product for restoration. Early efforts to use cement plaster were very unsatisfactory, so cement is not a substitute for sarooj.
There is no indication of the exact chemical composition of clays used as the basis for sarooj, and neither is there a description of the temperatures required for baking the sarooj bricks, nor the amounts of water and ground sarooj needed to make the plaster.
Answer:
It has taken me quite a while to trace some information in English.
I found it ultimately in a book by Maria Biancifiori, written in Italian originally. She finished the book in dedication to her brother Giuseppe, who worked on the restoration of Omani monuments from 1985 until he died in 1991. The title of the book is 'Works of Architectural Restoration in Oman.'
It is now out of print and only comes on to the second hand market rarely. You could try looking for it at www.abebooks.com although theoretically, you ought to be able to contact the Ministry of (National) Heritage and Culture for the information. I do not know whether the ministry would have the information available in English.
This extract comes from page 24 of the chapter on Materials and Techniques. The writer noted that it had been essential to speak to older members of the community who were the only ones who remembered the technique.
"The Ministry of National Heritage and Culture in Oman took care of the production of about 50% of the sarooj necessary for the projects described.
The raw material is the clayey earth taken from a date palm plantation, usually not far from the site of the building to be restored; in fact, the use of local earth is necessary in order to obtain in the restoration a structure and colour as similar as possible to the original.
This salt-free earth is mixed with water and made into flat cakes.
'Making sarooj is quite a procedure, but one which everyone enjoys - almost like children making mud pies.'
The cakes are put in the sun to dry and then carefully stacked, separated by wadi pebbles, on an enormous, carefully constructed pyre of date palm trunks. The whole structure is then covered with earth to form an airtight seal and the pyre is lit. The firing process lasts about a week. When the fire has died down, the mound is left for a few days to cool. The external layer of earth is then removed and all the residue, including the ashes, is ground to a powder which, when mixed with water, becomes sarooj.
When dry, sarooj takes on various tones of yellow ochre according to the zone of production.
Chemically, sarooj is similar to a hydraulic cement."
Sarooj with higher silicate content is a much better product for restoration. Early efforts to use cement plaster were very unsatisfactory, so cement is not a substitute for sarooj.
There is no indication of the exact chemical composition of clays used as the basis for sarooj, and neither is there a description of the temperatures required for baking the sarooj bricks, nor the amounts of water and ground sarooj needed to make the plaster.
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