Module 3: Material Characteristics and as a Building Material
This morning we visited Peter Rockwell's sculpture studio to test out some of the tools he has been teaching us about for ourselves.
30 April 2011
Saturday 30th April 2011; Historic Stone Working Techniques
Week 3 of 12
Module 3: Material Characteristics and as a Building Material
This morning we visited Peter Rockwell's sculpture studio to test out some of the tools he has been teaching us about for ourselves.
Module 3: Material Characteristics and as a Building Material
This morning we visited Peter Rockwell's sculpture studio to test out some of the tools he has been teaching us about for ourselves.
29 April 2011
Friday 29th April 2011; Tivoli Quarry and De Tomassi Workshop Visits
Week 3 of 12
Module 3: Material Characteristics and as a Building Material
We we were out of the classroom today accompanied by the Stone Course team, Peter Rockwell and David Jefferson.
Pacifici Masonry Yard, Tivoli
Large blocks or travertine were being transported around the yard and we saw many of the processes involved in the production of travertine cladding from cutting the stone into thin sheets (down to 10mm in width), filling the pores with mortar, polishing, cutting and packing. The team was currently processing stone which will be used in a new shopping centre in London.
Cutting the slabs.
The yard.
Stone Course participants examining the travertine.
Pacifici Travertine Quarry, Tivoli
After visiting the yard we were taken to the quarry where we were lucky enough to time our visit with the breaking of a large slab of stone.
De Tomassi (Stone Masonry) Workshop, Rome
After the quarry visit we went back into Rome and visited Mr De Tomassi at his masonry workshop where he uses a large number of traditional masonry techniques for working stone.
Mr De Tomassi, Simon Warrack and Peter Rockwell
Paper hats made from newspaper like the one in this photo are commonly worn by Italian stone carvers. The newspaper used apparently tells you the politics of the mason wearing the hat. Apparently the type of carvers are commonly divided by politics; generally 'roughing out' carvers are left leaning, fine finish carvers centre and none right leaning.
Chisels.
Peter Rockwell showing us how features can be measured for carving.
Module 3: Material Characteristics and as a Building Material
We we were out of the classroom today accompanied by the Stone Course team, Peter Rockwell and David Jefferson.
Pacifici Masonry Yard, Tivoli
Large blocks or travertine were being transported around the yard and we saw many of the processes involved in the production of travertine cladding from cutting the stone into thin sheets (down to 10mm in width), filling the pores with mortar, polishing, cutting and packing. The team was currently processing stone which will be used in a new shopping centre in London.
Cutting the slabs.
The yard.
Stone Course participants examining the travertine.
Pacifici Travertine Quarry, Tivoli
After visiting the yard we were taken to the quarry where we were lucky enough to time our visit with the breaking of a large slab of stone.
De Tomassi (Stone Masonry) Workshop, Rome
After the quarry visit we went back into Rome and visited Mr De Tomassi at his masonry workshop where he uses a large number of traditional masonry techniques for working stone.
Mr De Tomassi, Simon Warrack and Peter Rockwell
Chisels.
Peter Rockwell showing us how features can be measured for carving.
Thursday 28th April 2011; Working Techniques of Stone
Week 3 of 12
Module 3: Material Characteristics and as a Building Material
The sculptor Peter Rockwell this morning introduced us to 'Working Techniques of Stone' and this afternoon took us to some of the famous sites in Rome to illustrate his lecture; Basilica di Santa Maria sopra Minerva, Pulcino della Minerva, Pantheon, Piazza Navona and the Fontana dei Quattro Fiumi. He methodically introduced us to the different tools available to masons both in Italy and abroad and explained how the types of tools used have varied according to history and location. Peter explained the differences we may see between the finishes on sculptures including a true polish (a painstaking process of hand-polishing stone using various abrasives) and a false polish (wax applied to the carved surface of the stone- often resulting in brown staining).
I have always thought of sawn stone being a (relatively) recent development for masons, however the earliest known saw cut in stone was in Egypt in the 3rd Millennium BC. Commonly the saw that is used on a stone will not have a sharp blade or have 'teeth', but a water and abrasive mix is dripped into the cut and the stone is abraded away by the moving saw.
Stone workers / masons use geometry as a tool for calculating angles and designs rather than arithmetic- callipers are used as an instrument for measurement. Simon Warrack commented that he had once asked his teacher when he was an apprentice stone mason if his straight line was good and was told that something either is a straight line or is not a straight line, but there's no such thing as a good straight line. Most carved work that is composed of more than one piece of stone usually has a rough margin left so that it can be finished in place, because inevitably things will not line up as expected. We were shown how an unfinished piece of work- and the stage at which it has been left, can be identified by examining the tool marks present on the stone.
Peter presented the interesting case study of Easter Island which I believe was inhabited in the 4th Century AD and no-one else arrived on the island until the 18th Century. The forms of quarrying and stonework are therefore considered to be indigenous and show an interesting development in techniques. No metal was available on the island and therefore the harder stones were used as tools for working the softer stones. Easter island is famous for its mo'ai statues of which there are c.800 on the island- c.300 of which are unfinished. This gives us a fantastic insight into the stages of their creation and it can be seen that a large amount of the carving would have been done with the stone in situ in the quarry until it was necessary to move it to complete. The largest sculpture is 20m in height, although this one has not been moved from the quarry. The largest standing is 9m in height.
Many statues break at the ankles/legs because this is their weakest point. It is believed that the Ancient Greeks did their carvings horizontally on the ground and then stood them up to reduce the risk of breakage, whereas the Roman sculptors would have carved theirs standing up but incorporated a support into the design- commonly a tree trunk.
The grave of Andrea Bregno, a sculptor, is within the Basilica di Santa Maria sopra Minerva and the tomb has been decorated with many carvings of masons tools.
The ceiling in the pantheon, one of the few examples of a truely Roman building including most of the original, marble walling columns and flooring, the cast 'Roman cement' dome and brass doors. All as stunning as hoped for.
Fontana dei Quattro Fiumi (Fountain of the Four Rivers), 1651, designed and partially sculpted by Gian Lorenzo Bernini representing the World's for largest known rivers; Río de la Plata (S. America), Danube, Nile and Ganges. The base is formed of Travertine and the sculptures are white marble.
Close-up of 'Danube' who holds an oar to represent the longest known navigable river. The original tooling marks are visible on the oar and on some parts of the torso.
Module 3: Material Characteristics and as a Building Material
The sculptor Peter Rockwell this morning introduced us to 'Working Techniques of Stone' and this afternoon took us to some of the famous sites in Rome to illustrate his lecture; Basilica di Santa Maria sopra Minerva, Pulcino della Minerva, Pantheon, Piazza Navona and the Fontana dei Quattro Fiumi. He methodically introduced us to the different tools available to masons both in Italy and abroad and explained how the types of tools used have varied according to history and location. Peter explained the differences we may see between the finishes on sculptures including a true polish (a painstaking process of hand-polishing stone using various abrasives) and a false polish (wax applied to the carved surface of the stone- often resulting in brown staining).
I have always thought of sawn stone being a (relatively) recent development for masons, however the earliest known saw cut in stone was in Egypt in the 3rd Millennium BC. Commonly the saw that is used on a stone will not have a sharp blade or have 'teeth', but a water and abrasive mix is dripped into the cut and the stone is abraded away by the moving saw.
Stone workers / masons use geometry as a tool for calculating angles and designs rather than arithmetic- callipers are used as an instrument for measurement. Simon Warrack commented that he had once asked his teacher when he was an apprentice stone mason if his straight line was good and was told that something either is a straight line or is not a straight line, but there's no such thing as a good straight line. Most carved work that is composed of more than one piece of stone usually has a rough margin left so that it can be finished in place, because inevitably things will not line up as expected. We were shown how an unfinished piece of work- and the stage at which it has been left, can be identified by examining the tool marks present on the stone.
Peter presented the interesting case study of Easter Island which I believe was inhabited in the 4th Century AD and no-one else arrived on the island until the 18th Century. The forms of quarrying and stonework are therefore considered to be indigenous and show an interesting development in techniques. No metal was available on the island and therefore the harder stones were used as tools for working the softer stones. Easter island is famous for its mo'ai statues of which there are c.800 on the island- c.300 of which are unfinished. This gives us a fantastic insight into the stages of their creation and it can be seen that a large amount of the carving would have been done with the stone in situ in the quarry until it was necessary to move it to complete. The largest sculpture is 20m in height, although this one has not been moved from the quarry. The largest standing is 9m in height.
Many statues break at the ankles/legs because this is their weakest point. It is believed that the Ancient Greeks did their carvings horizontally on the ground and then stood them up to reduce the risk of breakage, whereas the Roman sculptors would have carved theirs standing up but incorporated a support into the design- commonly a tree trunk.
28 April 2011
Wednesday 27th April 2011; Stone the Unstable Building Material
Week 3 of 12
Module 3: Material Characteristics and as a Building Material
Module 3: Material Characteristics and as a Building Material
Our lectures continued with David Jefferson today on the topics ‘Stone the Unstable Building Material’ and ‘Identifying and Sourcing Stone for Historic Building Repair’. The majority of minerals in rocks are unstable because they were formed either under heat or pressure or both and have been transported to the Earth’s surface; David equated this to taking a block of ice to the Tropics. The most common building stone in Goa where the Indian participant is located is laterite, which is one exception to this rule because it was formed under surface conditions.
David holds a few (I believe) controversial views in terms of stone deterioration because he does not believe that salts are responsible for the initial mechanical breakage of stone, and likewise frost damage. It is widely accepted that many forms of salt crystallising within a pore space or ice forming in a pore space under certain circumstances will cause pressures (due to expansion) that result in the mechanical deterioration of the stone. I'm sure we will be revisiting this discussion at a later stage in the course and I'm interested to follow this up.
Lichens are very common in Scotland and therefore I was particularly interested in two case studies that David discussed about lichens on rock art in Scotland. Lichens can last for thousands of years and are dependent on being anchored to the stone. The evidence from the case studies seems to show that once anchored the lichens will cause no (further?) damage. When in place lichens are thought to create a waterproof surface and a thermal barrier. Removal of lichens could expose the surface of the stone to unknown levels of deterioration. This is the evidence from sandstone rock art in Scotland, however it is possible that in other climates and on other stone types lichens could be damaging. Moses on the other hand are widely believed to be damaging as they absorb and hold water.
The decision to remove deteriorating stone from a surface should always be approached with caution. It is necessary to identify the form of deterioration before removing the outer layer, because this could simply expose the underlying layer of stone to the same form of deterioration.
David showed some evidence that there can be problems when combining sandstones and limestones in a building due to the fluids that may pass from one stone to another causing a chemical reaction and deterioration of the stone. Equally there has been evidence that combining carbonate limestone with magnesium limestone results in deterioration, but so far no-one has come up with an explanation why!
David believes that combining a fat lime (non-hydraulic lime / high calcium lime) with sandstone can lead to the deterioration of the stone. Calcium limes have however been used in Scotland for as long as we know and I do not know of any known damage in this form. Later David said that he understands it to be the geological age of the sandstone that dictates if this form of deterioration occurs- sandstones which are Carboniferous (299 million years ago) or older- as most are in Scotland- either do not contain reactive silicas or only have a low level. Sandstones younger than this contain reactive silicas which react with high calcium lime. I am interested in reading further about this and would be interested to hear if anyone has experience of this or if you agree or disagree with this concept. David does not believe that Natural Hydraulic Limes (NHLs) exist, which I think is an debate he'll have to take up with the lime producers- it appears to be a disagreement about the terminology.
In week 11 of the course we will spend a week in the Non-Catholic Cemetery in Rome working on six of the tombs; creating a conservation plan and carrying out the work. This cemetery contains the tombs of many famous people including the British poets Shelley and Keats. We have been split into groups for this and I will be working with Anita (the Australian participant), who is an architect, on a tomb for Florence Baldwin (deceased 1919).
Lichens are very common in Scotland and therefore I was particularly interested in two case studies that David discussed about lichens on rock art in Scotland. Lichens can last for thousands of years and are dependent on being anchored to the stone. The evidence from the case studies seems to show that once anchored the lichens will cause no (further?) damage. When in place lichens are thought to create a waterproof surface and a thermal barrier. Removal of lichens could expose the surface of the stone to unknown levels of deterioration. This is the evidence from sandstone rock art in Scotland, however it is possible that in other climates and on other stone types lichens could be damaging. Moses on the other hand are widely believed to be damaging as they absorb and hold water.
The decision to remove deteriorating stone from a surface should always be approached with caution. It is necessary to identify the form of deterioration before removing the outer layer, because this could simply expose the underlying layer of stone to the same form of deterioration.
David showed some evidence that there can be problems when combining sandstones and limestones in a building due to the fluids that may pass from one stone to another causing a chemical reaction and deterioration of the stone. Equally there has been evidence that combining carbonate limestone with magnesium limestone results in deterioration, but so far no-one has come up with an explanation why!
David believes that combining a fat lime (non-hydraulic lime / high calcium lime) with sandstone can lead to the deterioration of the stone. Calcium limes have however been used in Scotland for as long as we know and I do not know of any known damage in this form. Later David said that he understands it to be the geological age of the sandstone that dictates if this form of deterioration occurs- sandstones which are Carboniferous (299 million years ago) or older- as most are in Scotland- either do not contain reactive silicas or only have a low level. Sandstones younger than this contain reactive silicas which react with high calcium lime. I am interested in reading further about this and would be interested to hear if anyone has experience of this or if you agree or disagree with this concept. David does not believe that Natural Hydraulic Limes (NHLs) exist, which I think is an debate he'll have to take up with the lime producers- it appears to be a disagreement about the terminology.
In week 11 of the course we will spend a week in the Non-Catholic Cemetery in Rome working on six of the tombs; creating a conservation plan and carrying out the work. This cemetery contains the tombs of many famous people including the British poets Shelley and Keats. We have been split into groups for this and I will be working with Anita (the Australian participant), who is an architect, on a tomb for Florence Baldwin (deceased 1919).
26 April 2011
Tuesday 26th April 2011; The Nature of Stone
Week 3 of 12
Module 3: Stone: Material Characteristics and as a Building Material
David Jefferson, a geologist and building stone speciallist from England, will be instructing us for the next couple of days on stone as a material. This morning he gave us lectures titled 'The Nature of Stone' followed by a session in the ICCROM laboratory this afternoon.
'Each and every stone is different and there are no universal remedies for the repair of stone' was the opening message of the lecture. In connection with Giacomo Chiari's lectures last week, David made the point that all stones are composed of minerals, some including basic elements and some including organic matter. We were shown samples of the wide variety of stone used historically in England and the issues now faced in correctly matching the stone for replacement. Apparently 80-85% of the conservation work that we now carry out is repairing previous restoration work.
In a discussion about quarrying we were shown how the natural bed height often dictates the course heights in historic buildings; these bedding planes were exploited to reduce the amount of cutting necessary because this meant that just the ends and sides would need to be cut to size. Apparently c.50% of wastage should be accounted for when specifying stone from a quarry as uncut 'block' because the excess needs to be removed to produced the required dimension stone. Historically limestone quarries were able to produce practically 0% wastage as the 'good' stone could be used as dimension stone, the wastage for rubble and fill, and any excess could be burnt for lime production.
This afternoon we were introduced to visual analysis of stone by the naked eye and by petrography.
Module 3: Stone: Material Characteristics and as a Building Material
David Jefferson, a geologist and building stone speciallist from England, will be instructing us for the next couple of days on stone as a material. This morning he gave us lectures titled 'The Nature of Stone' followed by a session in the ICCROM laboratory this afternoon.
'Each and every stone is different and there are no universal remedies for the repair of stone' was the opening message of the lecture. In connection with Giacomo Chiari's lectures last week, David made the point that all stones are composed of minerals, some including basic elements and some including organic matter. We were shown samples of the wide variety of stone used historically in England and the issues now faced in correctly matching the stone for replacement. Apparently 80-85% of the conservation work that we now carry out is repairing previous restoration work.
In a discussion about quarrying we were shown how the natural bed height often dictates the course heights in historic buildings; these bedding planes were exploited to reduce the amount of cutting necessary because this meant that just the ends and sides would need to be cut to size. Apparently c.50% of wastage should be accounted for when specifying stone from a quarry as uncut 'block' because the excess needs to be removed to produced the required dimension stone. Historically limestone quarries were able to produce practically 0% wastage as the 'good' stone could be used as dimension stone, the wastage for rubble and fill, and any excess could be burnt for lime production.
This afternoon we were introduced to visual analysis of stone by the naked eye and by petrography.
21 April 2011
Thursday 21st April 2011; Participant Presentations & Library
Week 2 of 12
Module 2: History and Theory of Conservation
Today we completed the talks given by the course participants with talks from the candidates representing Romania, Palestine, Russia, Portugal, Sri Lanka, Sudan and Syria. The candidates from Japan and Nigeria were absent but I hope we are also able to hear their presentations at a later stage. I was particularly interested by the presentation given by the Palestinian participant who works for RIWAQ, also a charity like the Scottish Lime Centre Trust. I realised that we are lucky in the fact that, in general, much of our population is keen to live in our historic towns and villages and to continue the use of our historic buildings. The issue being faced in Palestine is that many of the historic areas have been deserted and therefore RIWAQ are working together with the community to try to encourage people to care for their historic towns and villages and to repopulate them. Their projects provide skills training and employment in the short term and reuse of their heritage in the long term.
Paul Arenson, Chief Librarian, gave us a tour of the amazing library collection at ICCROM. The collection is available internationally and contains references in many different languages on all topics related to conservation. A special 'Stone' section has been prepared for our course.
Module 2: History and Theory of Conservation
Today we completed the talks given by the course participants with talks from the candidates representing Romania, Palestine, Russia, Portugal, Sri Lanka, Sudan and Syria. The candidates from Japan and Nigeria were absent but I hope we are also able to hear their presentations at a later stage. I was particularly interested by the presentation given by the Palestinian participant who works for RIWAQ, also a charity like the Scottish Lime Centre Trust. I realised that we are lucky in the fact that, in general, much of our population is keen to live in our historic towns and villages and to continue the use of our historic buildings. The issue being faced in Palestine is that many of the historic areas have been deserted and therefore RIWAQ are working together with the community to try to encourage people to care for their historic towns and villages and to repopulate them. Their projects provide skills training and employment in the short term and reuse of their heritage in the long term.
Paul Arenson, Chief Librarian, gave us a tour of the amazing library collection at ICCROM. The collection is available internationally and contains references in many different languages on all topics related to conservation. A special 'Stone' section has been prepared for our course.
Wednesday 20th April 2011; Porous Building Materials & Participant Presentations
Week 2 of 12
Module 2: History and Theory of Conservation
Giacomo Chiari, Chief Scientist at the Getty Conservation Institute, today gave us lectures on an 'Introduction to Porous Building Materials'.
The two major causes of destruction of buildings are man and water. Giacomo focussed on the latter, however he pointed out that it is very seldom that there is only one cause of deterioration, and that you should always look at the object, structure or building that you're conserving holistically. A large focus of the lectures was on the chemistry of the processes of deterioration that occur in porous materials. A quote Giacomo made in the forward of Giorgio Torraca's 'Lectures on Materials Science for Architectural Conservation' is that 'everything happens at atomic level'. Following today's lectures I find myself realising how true this is. It can be hard to perceive how water can move through micropores in a porous material considering that these pores are defined as being between 1-10 microns (1micron = 1,000th of a mm). However, it becomes easier to imagine that this is possible when you consider that if a water molecule was the size of a human, a 1micron pore would be the equivalent of 18km3 (18km is the height at which many planes fly). It is worth noting that with regard to building materials, it is only open (connected) porosity that is of interest to us.
The evaporation of water from a porous building material is one of the phases of concern with regard to stone deterioration. The rate of evaporation can affect the position that any soluble salts are precipitated. Any alteration to environmental conditions (wind, sun exposure or moisture) can drastically and quickly affect this rate and all too often result in salts being deposited below the surface of the stone- subfluorescence. If the concentration of salts is large enough to fill a pore this is where pressures become exerted on the walls of the pore and deterioration can occur as this process repeats itself. Giacomo showed some great time-lapse videos of subfluorescence and efflorescence which I will try to add if I can find them as electronic resources.
Porous building materials are brittle- they have a low tensile strength. Mortar between two blocks of stone allows the load of the overlying material to be evenly distributed across the stone below and removes the pressure on particular points that would occur if a stone does not have a surface that is entirely even (which is true in the majority of cases).
When telling us about how we should assess a building holistically Giacomo asked us to look at the wall in the classroom and tell him what we could see. He pointed out that our eyes were drawn to the red pins but not the grey board that they were attached to; this is a danger that we are so drawn to a single (or the most obvious) defect on a building that we forget to assess the background or less obvious parts.
We had a discussion about stone consolidants and identified the many necessary qualities that this material should have if it is to be used including water resistance, retaining the porosity, not altering the chemico-physical properties of the stone, increase resistance to desegregation.... the list continued. Perhaps we will identify if we have yet discovered such a material in later lectures on consolidants.
This afternoon we had further presentations from participants; Korea, Netherlands and from myself (Scotland). The Korean participant focussed on the issues they're dealing with in protecting their exposed Buddhist monuments and temples and the need for appropriate solutions for creating shelters or protecting the stone. The Dutch participant talked us through some of the work he has carried out on external sculptures an some of the problems he has faced during the process. It was pointed out that we have a lot to gain from hearing about others failures/mistakes/errors and is something we should all do a lot more, although these things are often hard to admit.
Following my presentation about the work that we carry out at the Scottish Lime Centre Trust and the conservation issues we face in Scotland, Giacomo shared with me some photos he had taken during a visit to Yemen where they continue to burn lime in traditional kilns which is used on the local buildings. The visit was connected with a film that was being made by Caterina Borelli 'The Architecture of Mud'.
Module 2: History and Theory of Conservation
Giacomo Chiari, Chief Scientist at the Getty Conservation Institute, today gave us lectures on an 'Introduction to Porous Building Materials'.
The two major causes of destruction of buildings are man and water. Giacomo focussed on the latter, however he pointed out that it is very seldom that there is only one cause of deterioration, and that you should always look at the object, structure or building that you're conserving holistically. A large focus of the lectures was on the chemistry of the processes of deterioration that occur in porous materials. A quote Giacomo made in the forward of Giorgio Torraca's 'Lectures on Materials Science for Architectural Conservation' is that 'everything happens at atomic level'. Following today's lectures I find myself realising how true this is. It can be hard to perceive how water can move through micropores in a porous material considering that these pores are defined as being between 1-10 microns (1micron = 1,000th of a mm). However, it becomes easier to imagine that this is possible when you consider that if a water molecule was the size of a human, a 1micron pore would be the equivalent of 18km3 (18km is the height at which many planes fly). It is worth noting that with regard to building materials, it is only open (connected) porosity that is of interest to us.
The evaporation of water from a porous building material is one of the phases of concern with regard to stone deterioration. The rate of evaporation can affect the position that any soluble salts are precipitated. Any alteration to environmental conditions (wind, sun exposure or moisture) can drastically and quickly affect this rate and all too often result in salts being deposited below the surface of the stone- subfluorescence. If the concentration of salts is large enough to fill a pore this is where pressures become exerted on the walls of the pore and deterioration can occur as this process repeats itself. Giacomo showed some great time-lapse videos of subfluorescence and efflorescence which I will try to add if I can find them as electronic resources.
Porous building materials are brittle- they have a low tensile strength. Mortar between two blocks of stone allows the load of the overlying material to be evenly distributed across the stone below and removes the pressure on particular points that would occur if a stone does not have a surface that is entirely even (which is true in the majority of cases).
When telling us about how we should assess a building holistically Giacomo asked us to look at the wall in the classroom and tell him what we could see. He pointed out that our eyes were drawn to the red pins but not the grey board that they were attached to; this is a danger that we are so drawn to a single (or the most obvious) defect on a building that we forget to assess the background or less obvious parts.
We had a discussion about stone consolidants and identified the many necessary qualities that this material should have if it is to be used including water resistance, retaining the porosity, not altering the chemico-physical properties of the stone, increase resistance to desegregation.... the list continued. Perhaps we will identify if we have yet discovered such a material in later lectures on consolidants.
This afternoon we had further presentations from participants; Korea, Netherlands and from myself (Scotland). The Korean participant focussed on the issues they're dealing with in protecting their exposed Buddhist monuments and temples and the need for appropriate solutions for creating shelters or protecting the stone. The Dutch participant talked us through some of the work he has carried out on external sculptures an some of the problems he has faced during the process. It was pointed out that we have a lot to gain from hearing about others failures/mistakes/errors and is something we should all do a lot more, although these things are often hard to admit.
Following my presentation about the work that we carry out at the Scottish Lime Centre Trust and the conservation issues we face in Scotland, Giacomo shared with me some photos he had taken during a visit to Yemen where they continue to burn lime in traditional kilns which is used on the local buildings. The visit was connected with a film that was being made by Caterina Borelli 'The Architecture of Mud'.
20 April 2011
Tuesday 19th April 2011; Interventions & Participant Presentations
Week 2 of 12
Module 2: History and Theory of Conservation
We received a second morning of lectures from Gionata Rizzi today, starting with 'Types of Intervention: Marrying Theory with Practice' followed by a case study on Palma Cathedral.
A few thoughts from the lectures:
- It is possible for limestone to turn into quicklime during a fire. Clearly significant temperatures would need to be reached and sustained for this to occur, but consider the reaction then if water is used to put out the fire.
- When discussing conservation a saying that Gionata mentioned is that 'we don't know what we don't know'. We do the best we can with the knowledge we have at the time. In hindsight we can see the mistakes we have made and this should warn us to approach with increasing caution but to make the best of the knowledge that we have.
- We are used to seeing large volumes of white stone when looking at historic sculpture and architecture; a large amount of this however is believed to have been highly painted and colourful when first complete; why do we accept the restoration of the structure in many cases but not the colour?
- The finish (tooling) on a stone can vastly affect its appearance and colour, which is also true of the use of certain cleaning techniques; small fractures in a stone can dramatically change its appearance in the same way that a block of ice turns from clear to white when fractured.
This afternoon we had the first set of presentations from course participants from Australia, Belgium, Brazil, China, Czech Republic, Denmark, Georgia and India. This group includes a wide range of backgrounds including a geologist, theoretical and practical conservators and architects. Many of the issues and materials discussed bore similarities to Scotland; notably from Australia and Denmark. Sydney appears to have faced similar problems in terms of locating appropriate replacement stone to many Scottish cities due to the cities eventually engulfing the quarries. They now have legislation allowing the bed rock to be investigated for quarrying and stockpiling prior to any construction works. The Indian participant is based in Goa and her local building stone is a laterite, which is vastly different to any type of stone I know of that we use in Scotland, it's bright yellow to bright red in colour and has a powdery surface but appears to be very hard. The other countries discussed similar rock types to those present in Scotland; sandstone, granite and limestone.
Module 2: History and Theory of Conservation
We received a second morning of lectures from Gionata Rizzi today, starting with 'Types of Intervention: Marrying Theory with Practice' followed by a case study on Palma Cathedral.
A few thoughts from the lectures:
- It is possible for limestone to turn into quicklime during a fire. Clearly significant temperatures would need to be reached and sustained for this to occur, but consider the reaction then if water is used to put out the fire.
- When discussing conservation a saying that Gionata mentioned is that 'we don't know what we don't know'. We do the best we can with the knowledge we have at the time. In hindsight we can see the mistakes we have made and this should warn us to approach with increasing caution but to make the best of the knowledge that we have.
- We are used to seeing large volumes of white stone when looking at historic sculpture and architecture; a large amount of this however is believed to have been highly painted and colourful when first complete; why do we accept the restoration of the structure in many cases but not the colour?
- The finish (tooling) on a stone can vastly affect its appearance and colour, which is also true of the use of certain cleaning techniques; small fractures in a stone can dramatically change its appearance in the same way that a block of ice turns from clear to white when fractured.
This afternoon we had the first set of presentations from course participants from Australia, Belgium, Brazil, China, Czech Republic, Denmark, Georgia and India. This group includes a wide range of backgrounds including a geologist, theoretical and practical conservators and architects. Many of the issues and materials discussed bore similarities to Scotland; notably from Australia and Denmark. Sydney appears to have faced similar problems in terms of locating appropriate replacement stone to many Scottish cities due to the cities eventually engulfing the quarries. They now have legislation allowing the bed rock to be investigated for quarrying and stockpiling prior to any construction works. The Indian participant is based in Goa and her local building stone is a laterite, which is vastly different to any type of stone I know of that we use in Scotland, it's bright yellow to bright red in colour and has a powdery surface but appears to be very hard. The other countries discussed similar rock types to those present in Scotland; sandstone, granite and limestone.
18 April 2011
Monday 18th April 2011; Roman Construction Techniques and Use of Stone
Module 2: History and Theory of Conservation
This morning we had lectures from Gionata Rizzi on 'Roman Construction Techniques' and Patrizio Pensabene on 'Stones in Roman Construction.'
Gionata is an architect and a consultant of UNESCO, ICCROM and the World Monuments Fund. We were given the etymology for many words used in construction (many of which date back to the Roman Empire or before) including the word 'street' which comes from the word 'strata' meaning layered; a street is composed of many layers to give it structure and stability. Columns are a common feature of Roman architecture and we discussed the benefits of monolithical shafts (those constructed of one piece of stone) in comparison to multi-drum columns (those constructed of a series of cylindrical pieces of stone placed on top of one another. It was originally understood that monolithical shafts would have a greater ability to survive earthquakes, however it has been discovered that due to their low centre of gravity they are easily toppled, whereas the multi-drum columns are able to adjust and move during ground movement, often becoming more stable.
Patrizio is a conservation architect and specialist in Roman construction materials, today he introduced us to many different types of stone present in ancient Rome. Marble was seen as a prestigious material and dominates Roman construction, however much of this is 'architectural marble' rather than geologically defined 'marble'. We were shown the main types of 'marble' present in Ancient Rome during the lecture and this afternoon during a walking tour around the buildings dating from this period (and later) we were able to identify these stone types. The majority of these stones come from Asia Minor and North Africa.
The Basilica di Santa Maria in Cosimedin has a fantastic example of a floor made out of beautifully cut small pieces of many of the different types of marble and stone; this type of flooring is known as 'opus sectile'. This variety of stone is likely to have come from previous buildings and has been recut to create this floor. The circular central pieces are likely to have come from ancient columns which have been sliced through.
The 'opus sectile' flooring in the Basilica di Santa Maria in Cosimedin, Rome.
Anastilosis; acceptable or not? The portico of the San Giorgio al Velabro (below) was blown up by a car bomb in 1993 and left in fragments which have since been pieced back together.
The Portico of San Giorgio al Velabro which has been rebuilt following destruction by a bomb.
We looked at a fountain on Piazza di Campitelli which was conserved in 2003. Simon Warrack (pointing in photo) was actively involved in the conservation but says that the state of the fountain 8 years later is probably worse than when they started the conservation. This is because no maintenance has been carried out and limescale has been able to rapidly redeposit on the stonework.
Conserved fountain, Piazza di Campitelli, Rome.15 April 2011
Friday 15th April 2011; Expectations Exercise, Collections Unit, Values & Authenticity, & International Charterts
Week 1 of 12
Module 1: Introductions and Orientation
Joe King with his 20€ note
Module 1: Introductions and Orientation
This morning we carried out an expectations exercise for what each of the participants hoped to get out of the course. The main themes that were discussed were: understanding and specifying mortars, conservation philosophies, documentation, networking, using science as a tool and types of repair and intervention.
We had a brief presentation from the collections unit here at ICCROM and a highlight was the discussion about the storage of collections when not on display which is easily discounted in its importance. A new website has been set up on this topic following global consultation www.re-rog.info.
Late morning and this afternoon the topic of discussion was values and authenticity presented by Joe King (ICCROM). We were presented with a number of good examples of how these work in practice including the Joe's 20€ note example where he demonstrated that this object can hold a range of different values:
- It can be seen as a piece of paper with ink and metal
- It can be seen as having an associated and recognised monetary value (i.e. 20€)
- It can have no value if presented in a small village in a country unconnected to Europe
- It can have a value far higher if it can be said that it was carried by someone important during an important event (e.g. if it was said to have been in JFK's pocket on the day he was shot- higher value to some more than others though)
- It can have personal emotional value if it is of personal significance (e.g. the first 20€ the earner has ever earned)
This same example was then given in regard to authenticity:
- If the 20€ note was said to be in JFK's pocket in 1963 it would be unauthentic because the euro did not exist then
- If the 20€ note turned out to be a fake it loses all monetary value
- This is a true story however, and because this note (which Joe discovered to be fake when it was too late to return it) is now a useful teaching tool, it has gained value despite lacking original authenticity
Joe King with his 20€ note
Joe concluded the day with a lecture on 'Concepts & International Doctrines, Charters and Organisations' with a focus on the UNESCO World Heritage List and mention of ICOMOS (International Council on Monuments and Sites) and the presence of the ICOMOS-ISCS (International Council on Monuments and Sites– International Scientific Committee for Stone) who have created the Illustrated Glossary on Stone Deterioration Patterns a very useful text for anyone involved in the documentation or assessment of stone deterioration.
Thursday 14th April 2011; A History & Theory of Conservation & Foro Romano
Week 1 of 12
Module 1: Introductions and Orientation
Cultural tourism is said to have developed from the 17th-18th centuries and hence the development at this time of the two approaches to handling historic buildings. Western ideals were therefore introduced to the concept of ‘Cultural Pleuralism’ defined by Jukka [possibly using someone else’s words] as ‘the recognition of nations with different cultures and different values, not necessarily commensurate.’
The two edges of the ruined part of the colosseum.
Module 1: Introductions and Orientation
This morning we received lectures from Jukka Jokilehto on a ‘History and Theory of Conservation.’ Jukka’s first lecture concentrated on the ‘Development of Policies and Concepts in the Conservation of Cultural Heritage.’ The photo (below) from the lecture gives an idea of the timeline that Jukka talked us through and a large proportion of the focus of today’s discussion was between the historical restoration and conservation approaches.
Jukka presenting this morning’s lecture on the ‘Development of Policies and Concepts in the Conservation of Cultural Heritage.’
Cultural tourism is said to have developed from the 17th-18th centuries and hence the development at this time of the two approaches to handling historic buildings. Western ideals were therefore introduced to the concept of ‘Cultural Pleuralism’ defined by Jukka [possibly using someone else’s words] as ‘the recognition of nations with different cultures and different values, not necessarily commensurate.’
An example where restoration may be considered appropriate today is with structures where the measurements were so precise when constructed that there is only one way in which a ruin could be re-built. This tends to be true of the Greek temples and the word ‘αναστήλωσις’ (‘anastilosis’), the Greek word meaning re-errect, is used in this context.
The second part of the morning focussed on ‘Restoration Theories in the 20th Century’ and ‘Cesare Brandi’s Theory of Conservation.’ This part of the discussion focussed more closely on the recent philosophical background to the conservation/restoration debate. It is interesting to note that Riegl (1857-1905) wrote that the conservative attitude was to reconstruct whilst the radical attitude was to conserve. The charter of Athens 1931 (essentially the conclusions of a conference held in Athens at this time) records the decision/consideration that we should abandon the idea of restoration and focus on conservation.
This afternoon Jukka and Simon Warrack took us for a tour around Ancient Rome (Foro Romano) visiting sites which put this morning’s theory into context. The colosseum is an excellent example of the restoration and conservation approaches in practice. The two broken edges of the circular structure have both been rebuilt to an extent, the western edge has been reconstructed in brick to replicate the original whilst the eastern edge has simply been consolidated retaining the position of the stonework at the time and without the loss of material. Neither is trying to act as a fake as they have clearly be constructed in a different material but both have their own philosophies to the conservation approach.
The two edges of the ruined part of the colosseum.
14 April 2011
Wednesday 13th April 2011; Welcome & An Introduction to the Architectural History of Rome
Week 1 of 12
Module 1: Introductions and Orientation
The course opened today at the ICCROM offices in Trastevere, Rome.
The ICCROM Director-General Mounir Bouchenaki welcomed us onto the 17th International Course on Stone Conservation, being held for the first time in Rome. We were also welcomed by Joseph King and Simon Warrack (the course coordinator) of ICCROM and Susan MacDonald of the Getty Conservation Institute. There are 20 participants in total, each representing a different country.
Australia, Belgium, Brazil, China, Czech Republic, Denmark, Georgia, India, Japan, Korea, Netherlands, Nigeria, Palestine, Romania, Russian Federation, Portugal, Sri Lanka, Sudan, Syria & Scotland
This afternoon Jukka Jokilehto (conservation architect, World Heritage Advisor to ICOMOS and consultant to UNESCO) gave us ‘An Introduction to the Architectural Heritage of Rome’. We were told that much of modern central Rome is 6-10 metres above the ground level of Ancient Rome. This is due to factors including flooding of the Tevere (Tiber) River (which runs through the centre of the city) depositing silt, the destruction of old buildings due to a high level of historic military action and continuous rebuilding over the top of what was essentially seen as ‘rubbish and debris’. This is essentially the same way in which a sedimentary rock deposit is created, through the accumulation and deposition of different layers of material. In this case, however, it’s centuries of deconstruction and reconstruction of a city. In addition, many buildings in Rome incorporate parts of historic buildings from single stones to full foundations. Tomorrow we will be going on a tour of Foro Romano (the Roman Forum).
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