Module 4: Deterioration Mechanisms; Methods of Survey & Analysis
We were mostly at our work site in the Non-Catholic Cemetery, Rome, today, mapping the deterioration patterns present on our assigned monuments/grave stones. The day started and ended in the classroom firstly discussing how we should approach this task, and at the end of the day discussing how each group had carried out the task and any issues faced. At the cemetery we met Nicolas Stanley Price who sits on the Board of Directors of the Cemetery and who is a past Director General of ICCROM.
Although the ICOMOS Glossary (see Day 20 (11.05.2011) is a fantastic resource, we realized that it is not always possible to follow it entirely. Many forms of deterioration could be seen to fall into more than one category, or within a group there were disagreements between the meaning of the descriptions given. We also found that some definitions were missing, such as where part of a structure appears to have integrity but when tapped it is clearly heard to be detaching from the substrate.
In Scotland we refer to this as being ‘boss’ (e.g. ‘the area of mortar around the window was boss’) but in Australia this is referred to as being ‘hollow’; we agreed on using the term ‘detaching’. Another definition missing from the glossary is a term that can be used when parts of a stone deteriorate due to their geological composition. I would probably refer to this as ‘preferential weathering’ but perhaps that does not define clearly enough that this is purely based on material characteristics.
In Scotland we refer to this as being ‘boss’ (e.g. ‘the area of mortar around the window was boss’) but in Australia this is referred to as being ‘hollow’; we agreed on using the term ‘detaching’. Another definition missing from the glossary is a term that can be used when parts of a stone deteriorate due to their geological composition. I would probably refer to this as ‘preferential weathering’ but perhaps that does not define clearly enough that this is purely based on material characteristics.
In the cemetery we have located a tomb in the same stone and of a similar design to the one Anita and I are conserving (see Day 17 (06.05.2011)). It is in the older part of the cemetery and approximately 100 years older than the tomb of Florence Baldwin. Repairs were carried out on this structure in the 1990s and this gives us an excellent opportunity to assess the success of the previous interventions for when we plan how we may wish to conserve our structure. We also took the opportunity to visit the grave of Keats which is also in this part of the cemetery.
Dear 'Student', I am Véronique Vergès-Belmin, you will meet me in two weeks as an instructor on the course on desalination. I have been coordinating the glossary, and I am very happy that it is used and critisized. hereafter, you will find my comments on your questions.
ReplyDeleteQUESTION :"part of a structure appears to have integrity but when tapped it is clearly heard to be detaching from the substrate":
COMMENT :The glossary is meant to be only descriptive (things you can see). In this way, you can describe deterioration from very far away.. (looking at a façade from the ground for instance). When you touch, you do not use only your eyes..You use an non destructive tool to assess deterioration. The feature you are describing falls within the family "detachment". And according to what you have probably seen when the detachment is complete, you can most probably classify it as "scaling" .. You can very well imagine on looking at the pictures on page 27 of the glossary, what will happen if you tap the sound stone close to the detached areas of contour scaling on the Robert bruce Monument or on the Kersanton stone!
QUESTION :"Another definition missing from the glossary is a term that can be used when parts of a stone deteriorate due to their geological composition. I would probably refer to this as ‘preferential weathering’ but perhaps that does not define clearly enough that this is purely based on material characteristics."
COMMENT : Description is description. When mapping, you have to stay in a phenomenological approach. In some way, you have to put yourself into the skin of a "dumb-genious-describer".When you say 'I need to give a name to this deterioration pattern because it is characteristic of such or such a stone" you are not any more in the field of description. You use your knowledge about the type of stone, to interpret such or such degradation pattern as being attached to this kind of stone: this is not anymore description. In mapping, you should have;: 1. stone types (map 1) -degradation patterns (map 2) and then only, you can say OK this degradation pattern is found only on this stone". I hope these comments will have been of some help to you!