Catalogue of Damage – Architectural Heritage

Catalogue of Damage – Architectural Heritage
Illustrated Glossary of Effects of war and of deterioration phenomena

Catalogue of Damage

Introduction

This illustrated glossary focuses on the description and definition of damage to building structures (as a generalizing term), which refers to changes that threaten a building as a whole or impair the preservation/longevity of its components.

For a damage diagnosis the determination of the cause is of great importance. For this reason, our Aleppo Built Heritage Documentation (and assessment) Project, have identified and typified the characteristic forms of damage to building structures and materials that exist in the city after the end of the fighting. This includes, besides listing the usual natural or anthropogenically caused forms of weathering, also the attempt to deal with the description of war-related damage and includes specific forms of material damage and destruction of building structures.

In the restoration / conservation of architectural monuments the following terms are usually used to describe the condition of preservation: Alteration, Damage, Decay, Degradation, Deterioration, Weathering and Loss. In this context, “Condition” always refers to the degree of any change in the structural substance and does not necessarily have a negative connotation. Any changes or alterations are only regarded as damage if they permanently impair and endanger the substance and appearance of a single object or entire building.

In the evaluation of conditions, certain values, beliefs and traditions always play a role. For example, traces of use or types of patina, can increase the value of an object for some, while for others they are merely an aesthetic impairment.

This glossary should be a valuable means of reference, a means of communication among those working in the field, a help in professional education and work. In this context, it is of primary importance to set up a common language; if degradation patterns can be shown, named and described, then they can be recognised and compared with similar ones in a more accurate way in further investigations.

The glossary is based on a selected word list of the most important technical terms in the field of monument conservation including a brief definition of the single phenomenon and information useful and required for the full understanding of each condition issue and its associated term. It includes images for each condition type and illustrates a term accurately and without the need for further explanation; the term as it is defined as an individual element within a built object. As a consequence, the terms do not relate to the description of the deterioration of a stone masonry structure as a whole.

The terminology of conditions may have some specific features, often related to the regional techniques and materials used, or specific characteristics of the cultural heritage in a particular country. It is influenced by the natural sciences, the arts and humanities, the engineering sciences, but also by traditional craftsmanship and artistic traditions. This fact might cause difficulties in communication and therefore the terminology should improve communication and co-operation among the different trades and actors on site, and communication among the multidisciplinary professionals and the interested public. It helps avoid misunderstandings and reduces the risk of bad practice in heritage preservation. 

Therefore, this glossary addresses a diverse range of readers:

  • professionals like architects, engineers, scientists, conservators, planners and practitioners, as well as craftsmen, to help them, as a reference, with their daily work;
  • administrative authorities, to give them a tool for communicating their tasks;
  • individuals, to give advice in understanding deterioration and preservation processes within their built environment

The categorization of condition and risk assessment is an effective tool for the preparation of reports and expert opinions to support decision makers and field experts alike.  In order to simplify assessments, for non-designated experts for material or structural damage, each type of condition is accompanied by its possible categorization in severity/degree (CC= Condition Class) and  risk assessment the urgency of intervention (UC= Urgency Class)

(Explanatory note: see Annex, Glossary of surface and material condition phenomena)

External References to glossaries

ICOMOS illustrated glossary on stone deterioration patterns, Monuments and Sites XV, 2008
Link to site: iscs.icomos.org/glossary.html | Link to PDF file.

EwaGlos, European Illustrated Glossary of Conservation Terms for wall paintings and architectural surfaces
Link to site |  Link to PDF file

Classification scheme – Working group “Natural Stones and Weathering”, RWTH Aachen
Link to site

Structural damages / Phenomena

caused by war, terrorist attacks or natural disasters

Kind of Damage: Structural Damage

Total loss and collapse

Cause of Damage:

  • Explosion / tunnel bomb,
  • Earthquake,
  • Impact by shelling,
  • Construction defects / settlement,
  • Shock wave,
  • Fire (heat)
Definition / Description:

Physically complete destruction and loss of a building or its readability

Refer to “Rubble / Debris Management – General Guideline

Condition Class:

total loss

CC4

Urgency Class:

intermediate term 1-3 years

UC1

Damage pattern, total destruction of al-Jalabi mosque, Aleppo, Syria
Damage pattern, total destruction of al-Jalabi mosque, Aleppo, Syria
Damage pattern, total loss, explosion crater of al-Madrasa (and mosque) al-Khusrawiyya, Aleppo, Syria
Damage pattern, total loss, explosion crater of al-Madrasa (and mosque) al-Khusrawiyya, Aleppo, Syria
Kind of Damage: Structural Damage

(Partial) collapse

Cause of Damage:

  • Impact by shelling,
  • Earthquake,
  • Shock wave,
  • Vibrations,
  • Load stress,
  • Fire (heat),
  • Use of incompatible materials / methods
Definition / Description:

Building heavily damaged, partially collapsed, destruction by impacts;
Loss of cohesive structural elements that come off from the building and fall down due to external influence

Refer to “Rubble / Debris Management – General Guideline

Condition Class:

major symptoms

CC3

Urgency Class:

short term within 1 year

UC2

Damage pattern, partly collapsed dome of al-Bahramiyya mosque, Aleppo, Syria
Damage pattern, partly collapsed dome of al-Bahramiyya mosque, Aleppo, Syria
Damage pattern, Partial collapse, of Barsin mosque, Aleppo, Syria
Damage pattern, partial collapse, of Barsin mosque, Aleppo, Syria
Kind of Damage: Structural Damage

(Multiple) mechanical damage

Cause of Damage:

  • Impact by shelling,
  • Construction defects / settlement,
  • Loose structural elements
  • Shock wave,
  • Vibrations,
  • Load stress,
  • Fire (heat),
Definition / Description:

Building heavily damaged, partially collapsed, destruction by impacts/ shelling;
Multiple forms and intensities of damage; severe losses, deformations, cracks, loose structural elements, bullet holes/ impacts;
Loss of components or building elements that come off the building and fall down

Refer to “Rubble / Debris Management – General Guideline

Condition Class:

major symptoms

CC3

Urgency Class:

short term within 1 year

UC2

Damage pattern, multiple damages in old municipality building, Aleppo
Damage pattern, multiple damages in old municipality building, Aleppo
Damage pattern, multiple damages in building of the Mufti's residence, Aleppo
Damage pattern, multiple damages in building of the Mufti’s residence, Aleppo
Kind of Damage: Cracks & Deformation

Fracture / Structural crack

Cause of Damage:

  • Impact by shelling,
  • Earthquake,
  • Construction defects / settlement,
  • Shock wave,
  • Vibrations,
  • Load stress,
  • Fire (heat),
  • Use of incompatible materials / methods
Definition / Description:

Individual fracture, clearly visible by naked eye, crosses completely the building element due to separation of one part from another.
Construction-related cracks occur due to changes in position, shape or volume of the construction.
A crack causes a visible separation of one part from another, that extends through one or more layers.
A crack is at least 0,2 mm wide and visible to the naked eye.

Condition Class:

major symptoms

CC3

Urgency Class:

short term within 1 year
to urgent within 3 month

UC2 UC3

Constructive crack pattern in masonry wall; al-Madrasa at-Turuntaʾiyya, Aleppo, Syria
Constructive crack pattern in masonry wall; al-Madrasa at-Turuntaʾiyya, Aleppo, Syria
Constructive crack pattern in masonry wall; al-Madrasa at-Turuntaʾiyya, Aleppo, Syria
Constructive crack pattern in masonry wall; al-Madrasa at-Turuntaʾiyya, Aleppo, Syria
Damage pattern, fractures in masonry of a pillar, Jarash, Jordan
Damage pattern, fractures in masonry of a pillar, Jarash, Jordan
Kind of Damage: Cracks & Deformation

Deformation: bulging, swelling

Cause of Damage:

  • Impact by shelling (e.g. shock wave),
  • Construction defects / settlement,
  • Static defects (e.g. load stress),
  • Fire (heat),
  • Water impact,
  • Inappropriate building technique / materials or repair
Definition / Description:

Individual fracture, clearly visible by naked eye, crosses completely the building element due to separation of one part from another.
Construction-related cracks occur due to changes in position, shape or volume of the construction.
A crack causes a visible separation of one part from another, that extends through one or more layers.
A crack is at least 0,2 mm wide and visible to the naked eye.

Condition Class:

minor symptoms
to moderate symptoms

CC1 CC2

Urgency Class:

intermediate term 1-3 years
to long term

UC1 UC0

Damage pattern, wall bulging
Damage pattern, masonry wall bulging
Damage pattern, deformation, bulging of a wall in a historic lane, al-Jallum, Aleppo
Damage pattern, deformation, bulging of a wall in a historic lane, al-Jallum, Aleppo
Kind of Damage: Detachments

Delamination / separation of walls

Cause of Damage:

  • Impact by shelling,
  • Earthquake,
  • Construction defects / settlement,
  • Shock wave,
  • Vibrations
  • Load stress,
  • Use of incompatible materials / methods
Definition / Description:

Vertical fracture, clearly visible by naked eye, crosses the wall parallel to its surface, due to separation of one layer or shell from another.

Condition Class:

major symptoms

CC3

Urgency Class:

urgent and immediate, within 3 month

UC3

Damage pattern, delamination/ separation of wall leaves, ar-Rumi mosque, Aleppo
Damage pattern, delamination/ separation of wall leaves, ar-Rumi mosque, Aleppo
Damage pattern, delamination/ separation of wall leaves, San Salvatore, Campi, Perugia, Italy
Damage pattern, delamination/ separation of wall leaves, San Salvatore, Campi, Perugia, Italy
Damage pattern, delamination/ separation of wall leaves, Ibshir Basha foundation, Aleppo
Damage pattern, delamination/ separation of wall leaves, Ibshir Basha foundation, Aleppo
Damage pattern, delamination/ separation of wall leaves, San Salvatore, Campi, Perugia, Italy
Damage pattern, delamination/ separation of wall leaves, San Salvatore, Campi, Perugia, Italy
Kind of Damage: Material loss – mechanical damage, Detachment

Shelling: shrapnel, bullet holes

Cause of Damage:

  • Impact by shelling,
  • Impact by shrapnel and bullets,
Definition / Description:

Locally limited superficial or substantial damage to the structure or building component due to crater-shaped impact caused by (artillery) grenades

Predominantly superficial damage to buildings or building components due to numerous irregular crater-shaped impacts of various sizes caused by bullets from firearms

Refer to Gaps, bursting (breakout)

Condition Class:

moderate symptoms

CC2

Urgency Class:

intermediate term (1-3 years)

UC1

Damage pattern, detachment thru shrapnel on stone surface in the Great Umayyad Mosque in Aleppo
Damage pattern, detachment thru shrapnel on stone surface in the Great Umayyad Mosque in Aleppo
Damage pattern, hole-shaped detachments in the stone surface due to bullet craters on the portal of the at-Tawashi mosque, Aleppo
Damage pattern, hole-shaped detachments in the stone surface due to bullet craters on the portal of the at-Tawashi mosque, Aleppo
Damage pattern, detachment thru shrapnel on stone surface in the Great Umayyad Mosque in Aleppo
Damage pattern, detachment thru shrapnel on stone surface in the Great Umayyad Mosque in Aleppo
Damage pattern, bullet hole damages in Saffahiyya mosque, Aleppo
Damage pattern, bullet hole damages in Saffahiyya mosque, Aleppo
Kind of Damage: Material loss – mechanical damage

Missing construction components

Cause of Damage:

  • Impact by shelling,
  • Shock wave / vibrations,
  • Load stress
Definition / Description:

Locally limited substantial damage to a building component due to external effects or static defects (e.g. internal pressure/ force), leading to loss and decay

Condition Class:

moderate symptoms
to major symptoms

CC2 CC3

Urgency Class:

urgent and immediate, within 3 month

UC3

Damage pattern, missing pillar, arcade of the cloister, St. Pierre, La Romieux, France
Damage pattern, missing pillar, arcade of the cloister, St. Pierre, La Romieux, France
Damage pattern, missing column in al-ʿAdiliyya mosque, Aleppo
Damage pattern, missing column in al-ʿAdiliyya mosque, Aleppo

Kind of Damage: Material loss – mechanical damage, Cracks & deformation

Loose construction components

Cause of Damage:

  • Impact by shelling,
  • Earthquake,
  • Shock wave,
  • Vibrations
  • Load stress
Definition / Description:

Locally limited substantial damage to the building component due to external effects, static defects (e.g. internal pressure/force), causing loss of bonding and cohesion of the components leads to subsequent damage

Condition Class:

moderate symptoms
to major symptoms

CC2 CC3

Urgency Class:

urgent and immediate, within 3 month

UC3

Damage pattern, loose construction elements, remaining after a hole caused by shelling, Madrasat al-Firdaws, Aleppo
Damage pattern, loose construction elements, remaining after a hole caused by shelling, Madrasat al-Firdaws, Aleppo
Damage pattern, loose construction components in the dome stone construction of Salih al-Hal mosque, Aleppo
Damage pattern, loose construction components in the dome stone construction of Salih al-Hal mosque, Aleppo
Damage pattern, loose elements after partial collapse of a wall in a historic house, Dar al-Agha, Aleppo
Damage pattern, loose elements after partial collapse of a wall in a historic house, Dar al-Agha, Aleppo

Kind of Damage: Material loss – mechanical damage, Cracks & deformation

Gaps, bursting

Cause of Damage:

  • Impact by shelling,
  • Disgrace
Definition / Description:

Local loss of building components due to external effects, leading to loss and decay;
Gaps and lacunas leads to decay and to a disturbance of the architectural surface and affect the perception and integrity of a building.

Refer to Shelling, shrapnel, bullet holes

Condition Class:

moderate symptoms
to major symptoms

CC2 CC3

Urgency Class:

short term (within 1 year)
to intermediate term (1-3 years)

UC2 UC1

Damage pattern, gap in Saffahiyya mosque minaret, Aleppo
Damage pattern, gap in Saffahiyya mosque minaret, Aleppo
Damage pattern, gap and bursting in a terracotta relief, Admiralspalast, fassade Planckstraße, Berlin
Damage pattern, gap and bursting in a terracotta relief, Admiralspalast, façade Planckstraße, Berlin

Damage of materials

caused by alteration, deterioration and weathering

Kind of Damage: Material losses, Detachment

Corrosion

Cause of Damage:

  • Water infiltration / increase in volume,
  • Material characteristics,
  • Inappropriate repair
Definition / Description:

The influence of carbon dioxide (CO2) and water (H2O) causes corrosion on (base) metals. Corroded metal can expand in volume many times over and thus lead to the breaking/ chipping of (building) components.

Note: this is not a damage phenomenon in the strict sense, but an important cause of various related consequential phenomena

Condition Class:

moderate symptoms
to major symptoms

CC2 CC3

Urgency Class:

short term (within 1 year)
to intermediate term (1-3 years)

UC2 UC1

Damage pattern, corrosion of an iron connector led to cracks and outburst, Acropolis, Athens
Damage pattern, corrosion of an iron connector led to cracks and outburst, Acropolis, Athens
Damage pattern, corrosion in sculpture of reinforced concrete with iron beams, Admiralspalast, fassade Planckstraße, Berlin
Damage pattern, corrosion in sculpture of reinforced concrete with iron beams, Admiralspalast, façade Planckstraße, Berlin

Water infiltration / Rising damp

Cause of Damage:

  • Weathering,
  • Water infiltration,
  • (Hygroscopic) Salts,
  • Material characteristics,
  • Exposition,
  • Building defects,
  • Sealing the ground
Definition / Description:

The ingress of water through defects in a building or rise of ground water in conjunction with porous building materials (capillary water absorption).

Note: this is not a damage phenomenon in the strict sense, but an important cause of various related consequential phenomena

Condition Class:

moderate symptoms

CC2

Urgency Class:

short term (within 1 year)
to intermediate term (1-3 years)

UC2 UC1

Damage pattern, water infiltration, on render on brick masonry, Old city center, Warsaw, Poland
Damage pattern, water infiltration, on render on brick masonry, Old city center, Warsaw, Poland
Damage pattern, rising dump at brickwork with stones, Marrakech, Morocco
Damage pattern, rising dump at brickwork with stones, Marrakech, Morocco

Air pollutants

Cause of Damage:

  • Weathering,
  • Water infiltration,
  • Salts,
  • Material characteristics,
  • Exposition,
  • Building defects,
  • Sealing the ground
Definition / Description:

The ingress of water through defects in a building or rise of ground water in conjunction with porous building materials (capillary water absorption).

Note: this is not a damage phenomenon in the strict sense, but an important cause of various related consequential phenomena

Condition Class:

minor symptoms
to moderate symptoms
to major symptoms

CC1 CC2 CC3

Urgency Class:

short term (within 1 year)
to intermediate term (1-3 years)

UC2 UC1

Damage pattern, air pollution pattern on sandstone, Angkor Wat, Cambodia
Damage pattern, air pollution pattern on sandstone, Angkor Wat, Cambodia
Damage pattern, air pollution (acid rain) on sandstone, Cathedral of Bamberg, Germany
Damage pattern, air pollution (acid rain) on sandstone, Cathedral of Bamberg, Germany

Fire damage

Cause of Damage:

  • Heat / fire,
  • Discoloration,
  • Deposits-Soiling,
  • Change of material characteristics, …
Definition / Description:

Fire causes serious material changes (superficial, inner structure) up to complete destruction; the aesthetic perception is strongly affected.

Note: this is not a damage phenomenon in the strict sense, but an important cause of various related consequential phenomena

Condition Class:

moderate symptoms
to major symptoms

CC2 CC3

Urgency Class:

short term (within 1 year)
to intermediate term (1-3 years)

UC2 UC1

Damage pattern, superficial fire traces on facade of limestone, Khan as-Sabun, Aleppo, Syria
Damage pattern, superficial fire traces on facade of limestone, Khan as-Sabun, Aleppo, Syria
Damage pattern, fire damage disintegration on limestone, Suq as-Sabun market lane, Aleppo, Syria
Damage pattern, fire damage disintegration on limestone, Suq as-Sabun market lane, Aleppo, Syria
Damage patterns in the Great Umayyad Mosque in Aleppo
Damage patterns in the Great Umayyad Mosque in Aleppo
Kind of Damage: Detachment

Delamination / exfoliation

Cause of Damage:

  • Deterioration,
  • Weathering,
  • Material characteristics, …
Definition / Description:

Detachment process affecting laminated stones (most of sedimentary rocks, some metamorphic rocks). It corresponds to a physical separation into one or several layers following the stone laminae. The thickness and the shape of the layers are variable. The layers may be oriented in any direction with regards to the stone surface.
Sandstone exfoliation: This subtype of delamination is characterized by a detachment of multiple thin stone layers sub-parallel to the stone surface. (ICOMOS Glossary on stone deterioration patterns).

Condition Class:

moderate symptoms
to major symptoms

CC2 CC3

Urgency Class:

short term (within 1 year)
to intermediate term (1-3 years)

UC2 UC1

Damage pattern, delamination/exfoliation in lime-sandstone, Zeitz, Germany
Damage pattern, delamination/exfoliation in lime-sandstone, Zeitz, Germany
Damage pattern, detachment in gypsum stone, Thuringia, Germany
Damage pattern, detachment in gypsum stone, Thuringia, Germany
Damage pattern, exfoliation, sandstone, Heidelberg, Germany
Damage pattern, exfoliation, sandstone, Heidelberg, Germany
Kind of Damage: Detachment

Scaling

Cause of Damage:

  • Deterioration,
  • Weathering,
  • Material characteristics,
  • Inappropriate repair,
  • Sometimes due to (organic) consolidants,
  • Freeze-thaw change
Definition / Description:

Surface-parallel detachment of the rock surface in the form of (multilayer) shells. The thickness of the shells is generally a few millimetres to centimetres. The phenomenon can occur locally as well as over a large area.
Scaling is often associated with moisture and salt crystallization on architectural surfaces of limestone or
sandstone.
Detachment of stone as a scale or a stack of scales, not following any stone structure and detaching like fish scales or parallel to the stone surface. (ICOMOS Glossary on stone deterioration patterns).

Condition Class:

moderate symptoms
to major symptoms

CC2 CC3

Urgency Class:

short term (within 1 year)
to intermediate term (1-3 years)

UC2 UC1

Damage pattern, scaling in tufa / tuffstone column, Guadalajara, Mexico
Damage pattern, scaling in tufa / tuffstone column, Guadalajara, Mexico
Damage pattern, scaling in sandstone masonry, Arrezzo, Italy
Damage pattern, scaling in sandstone masonry, Arrezzo, Italy
Damage pattern, single scaling in sandstone, Castle, Ludwigsburg, Germany
Damage pattern, single scaling in sandstone, Castle, Ludwigsburg, Germany
Kind of Damage: Detachment > Scaling

Spalling/ contour scaling

Cause of Damage:

  • Deterioration,
  • Weathering,
  • Impacts,
  • Material characteristics,
  • Freeze-thaw change
Definition / Description:

Local loss of the stone surface due to internal pressure, weathering or external influences;
Detachment of stone as a scale or a stack of scales, not following any stone structure and detaching like fish scales or parallel to the stone surface. The thickness of a scale is generally of millimetre to centimetre Scale;
Contour scaling: scaling in which the interface with the sound part of the stone is parallel to the stone surface. In the case of flat surfaces, contour scaling may be called spalling.
(ICOMOS Glossary on stone deterioration patterns).

Condition Class:

moderate symptoms
to major symptoms

CC2 CC3

Urgency Class:

short term (within 1 year)
to intermediate term (1-3 years)

UC2 UC1

Damage pattern, spalling at granite column, Topkapi Palace, Istanbul, Turkey
Damage pattern, spalling at granite column, Topkapi Palace, Istanbul, Turkey
Damage pattern, contour scaling in sandstone, Lucca, Italy
Damage pattern, contour scaling in sandstone, Lucca, Italy
Damage pattern, back weathering, limestone, Cairo, Egypt
Damage pattern, back weathering, limestone, Cairo, Egypt
Kind of Damage: Detachment > Disintegration

Sugaring/ Crumbling

Cause of Damage:

  • Deterioration,
  • Weathering,
  • Effects of salts,
  • Material characteristics,
  • Freeze-thaw change
Definition / Description:

Detachment of single grains or aggregates of grains. It affects mostly the surface of the stone or can occur in depth. On crystalline marble, granular disintegration may reach several centimeters in depth, sometimes more.
Stones may display deterioration patterns intermediate between granular disintegration and crumbling, scaling or delamination. (ICOMOS Glossary on stone deterioration patterns).

Condition Class:

moderate symptoms

CC2

Urgency Class:

intermediate term (1-3 years)

UC1

Damage pattern of crumbling/ sugaring on sandstone, Angkor Wat, Cambodia
Damage pattern of crumbling/ sugaring on sandstone, Angkor Wat, Cambodia
Damage pattern, crumbling in sandstone, Wittenberg, Germany
Damage pattern, crumbling in sandstone, Wittenberg, Germany
Damage pattern, crumbling in limestone, City wall, Cairo, Egypt
Damage pattern, crumbling in limestone, City wall, Cairo, Egypt
Kind of Damage: Detachment > Disintegration

Sanding/ Powdering

Cause of Damage:

  • Deterioration,
  • Weathering,
  • Water infiltration,
  • Effects of salts,
  • Material characteristics
Definition / Description:

Separation of individual stone particles or grain aggregates. Usually starting at the surface and then progressing to depth.
The term sanding is commonly used for sandstone and for limestone it is called powdering.

Condition Class:

moderate symptoms

CC2

Urgency Class:

intermediate term (1-3 years)

UC1

Damage pattern, sanding in sandstone, Fatipur Sikri, India
Damage pattern, sanding in sandstone, Fatipur Sikri, India
Damage pattern, powdering in limestone, Cathedral, Cadiz, Spain
Damage pattern, powdering in limestone, Cathedral, Cadiz, Spain
Damage pattern, sanding in sandstone, University, Aachen, Germany
Damage pattern, sanding in sandstone, University, Aachen, Germany
Kind of Damage: Material loss

Alveolization

Cause of Damage:

  • Weathering,
  • Water infiltration,
  • Effects of salts,
  • Material characteristics
Definition / Description:

Formation, on the stone surface, of cavities (alveoles) which may be interconnected and may have
variable shapes and sizes (generally centimetric, sometimes metric).
Alveolization is a kind of differential weathering possibly due to inhomogeneities in physical or chemical properties of the stone. (ICOMOS Glossary on stone deterioration patterns).

Condition Class:

moderate symptoms
to major symptoms

CC2 CC3

Urgency Class:

short term (within 1 year)
to intermediate term (1-3 years)

UC2 UC1

Damage pattern, alveolarization in limestone, Avignon, France
Damage pattern, alveolarization in limestone, Avignon, France
Damage pattern, alveolization of a porous limestone, Citadel, Malta, Victoria – Gozo
Damage pattern, alveolization of a porous limestone, Citadel, Malta, Victoria – Gozo
Kind of Damage: Material loss

Erosion by wind

Cause of Damage:

  • Deterioration,
  • Weathering,
  • Abrasion,
  • Material characteristics
Definition / Description:

The slow deterioration or abrasion of architectural surfaces, usually caused by the natural influence of wind-borne particles (such as dust, sand). Wind erosion can lead to rounded shapes (rounding).

Condition Class:

moderate symptoms
to major symptoms

CC2 CC3

Urgency Class:

intermediate term (1-3 years)

UC1

Damage pattern, wind erosion, sandstone, Necropols; Petra, Jordan
Damage pattern, wind erosion, sandstone, Necropols; Petra, Jordan
Damage pattern, wind erosion, sandstone, ancient city columns; Petra, Jordan
Damage pattern, wind erosion, sandstone, ancient city columns; Petra, Jordan
Kind of Damage: Material loss

Hollow areas / cavity

Cause of Damage:

  • Water infiltration,
  • Effects of salts,
  • Freeze-thaw change,
  • Deterioration,
  • Material characteristics
Definition / Description:

Local or partial detachment of a layer of plaster from the masonry due to loss of adhesion. Often not visible by the naked eye. As a result, there is a risk of falling and loss of the historical surface.

Condition Class:

moderate symptoms
to major symptoms

CC2 CC3

Urgency Class:

short term (within 1 year)
to intermediate term (1-3 years)

UC2 UC1

Damage pattern, hollow area, in plaster on sandstone, Franciscan monastery, Zeitz, Germany
Damage pattern, hollow area, in plaster on sandstone, Franciscan monastery, Zeitz, Germany
Kind of Damage: Discoloration & Deposits

Deposits/ soiling

Cause of Damage:

  • Weathering,
  • Material characteristics,
  • Exposition
  • Building defects, air pollution (dust, fine particles),
  • Animals (excrements),
  • Neglect
Definition / Description:

Accumulation of exogenous material of variable thickness, as typically deposits in the form of soot, dust or any kind of dirt, even from animals. These deposits can form crusty deposits in combination with moisture and air pollutants.
A deposit can be described for color, morphology, size and if possible nature and/or origin.

Condition Class:

minor symptoms
to moderate symptoms

CC1 CC2

Urgency Class:

intermediate term (1-3 years)

UC1

Damage pattern, deposit/ soiling, at limestone, Lugano, Switzerland
Damage pattern, deposit/ soiling, at limestone, Lugano, Switzerland
Damage pattern, soiling due to fauna / wildlife, Florence, Italy
Damage pattern, soiling due to fauna / wildlife, Florence, Italy

Kind of Damage: Discoloration & Deposits

Crusts

Cause of Damage:

  • Air pollution (Sulphur dioxide, dust, fine particles),
  • Weathering,
  • Material characteristics,
  • Exposition
Definition / Description:

A crust is a coherent accumulation of substances on the surface. Black crusts generally develop in urban environments on surfaces that are protected from direct rain and run-off water. They usually adhere very firmly to the substrate and consist mainly of particles from the air, which are fixed in a gypsum matrix (CaSO4 * 2 H2O).
They can be of uniform or irregular thickness and trace the stone surface; the crust can create tensions and detach from the surface with the upper stone matrix; crusts influence the esthetic appearance making details of the stone surface more difficult to see.

Condition Class:

minor symptoms
to moderate symptoms
to major symptoms

CC1 CC2 CC3

Urgency Class:

short term (within 1 year)
to intermediate term (1-3 years)

UC2 UC1

Damage pattern, crust on marble, sculpture, Schlossbrücke, Berlin, Germany
Damage pattern, crust on marble, sculpture, Schlossbrücke, Berlin, Germany
Damage pattern, gypsum crust on limestone, Reims, France
Damage pattern, gypsum crust on limestone, Reims, France
Damage pattern, crust on sandstone, detachment due to tensions, Castle, Hannover, Germany
Damage pattern, crust on sandstone, detachment due to tensions, Castle, Hannover, Germany

Decay caused by salts

Cause of Damage:

  • Weathering,
  • Water infiltration,
  • (Hygroscopic) Salts,
  • Material characteristics,
  • Exposition,
  • Building defects,
  • Sealing of the ground,
  • Air pollution
Definition / Description:

Salts can cause great damage in porous materials such as sandstone, and bricks. They usually occur in connection with any kind of water infiltration. The damage mechanisms are based on dissolving the structure due to crystallization processes in the pore space (changes of the physical-chemical conditions). In individual cases, several damage processes can also interact. In general, the type of damage caused by
soluble salts is related to the location of their crystallization.
The nature of the damage can be broadly divided into two main categories:
Efflorescence (salt crystallization at the surface) and
Subfluorescence (salt crystallization beneath the surface of the object).
Although visually alarming, efflorescence is in general as less harmful than subfluorescence, which might cause the disruption and loss of the object’s surface. The most important salts, which are structurally damaging buildings, are sodium chloride, sulphate, magnesium sulphate, calcium sulphate…

Note: this is not a damage phenomenon in the strict sense, but an important cause of various related consequential phenomena

Condition Class:

moderate symptoms
to major symptoms

CC2 CC3

Urgency Class:

intermediate term (1-3 years)

UC1

Damage pattern, decay by salts on rendered sandstone, Red Fortress, Agra, India
Damage pattern, decay by salts on rendered sandstone, Red Fortress, Agra, India
Damage pattrern, efflorecence on limestone, Mosque, Cairo, Egypt
Damage pattrern, efflorecence on limestone, Mosque, Cairo, Egypt
Damage pattern, subflorescence, sandstone, Horus Temple, Edfu, Egypt
Damage pattern, subflorescence, sandstone, Horus Temple, Edfu, Egypt

Kind of Damage: Biological colonization

Biological impact

Cause of Damage:

  • Climate,
  • Weathering,
  • Exposition,
  • Material characteristics,
  • Building defects,
  • Neglect
Definition / Description:

Colonization of an object or building with living organisms, which can lead to damage or decay because the plant is able to penetrate into gaps and joints while damaging the substance by increasing its volume (with all side effects).
Symbiotic relationships between plants and building fabric are not excluded in exceptional cases.
Colonization can be by many types of living organisms, from the simplest (bacteria, fungi, lichens and algae) to more complex species, such as higher plants (trees and bushes) and animals (bird droppings and nests). This can lead to irreversible loss of value and information.

Condition Class:

minor symptoms
to moderate symptoms
to major symptoms

CC1 CC2 CC3

Urgency Class:

short term (within 1 year)
to intermediate term (1-3 years)

UC2 UC1

Damage pattern, biological colonization, roots of a tree, Angkor Wat, Cambodia
Damage pattern, biological colonization, roots of a tree, Angkor Wat, Cambodia
Damage pattern, biological colonization by plants, due to neglect, Havanna, Kuba
Damage pattern, biological colonization by plants, due to neglect, Havanna, Cuba
Damage pattern, biological colonization by plants, due to neglect, Barsin mosque, Aleppo, Syria
Damage pattern, biological colonization by plants, due to neglect, Barsin mosque, Aleppo, Syria

Effects of use

Kind of Condition: Effects of use

Traces of use / Patina

Cause of Damage:

  • Wear and tear through use,
  • Abrasion,
  • Scratches
Definition / Description:

A natural alteration which appears at the surface of various materials due to ageing, use, handling, oxidation, and/or exposure to the environment.

Without disfiguring the surface, a patina is essentially an intrinsic part of the material. Sometimes a patina can be a protective layer, as in the case, for instance, of calcium oxalate. Patinas can also be synthetically made with chemicals.
The repeated abrasion effect of feet has led to the formation of a depression on this stone pavement element.

Note: this is not a damage phenomenon in the strict sense, but an important cause of various related consequential phenomena

Condition Class:

minor symptoms

CC1

Urgency Class:

without need to action

 UC-

Damage pattern of cuts in sandstone, with traces of knife sharpening, Market church, Goslar, Germany
Damage pattern of cuts in sandstone, with traces of knife sharpening, Market church, Goslar, Germany
Damage pattern, anthropogenic impact on sandstone, Karnak Temple, Luxor, Egypt
Damage pattern, anthropogenic impact on sandstone, Karnak Temple, Luxor, Egypt
Damage/Condition pattern of patina on Neptunbrunnen, bronze sculpture with patina by stroke, Berlin, Germany
Damage/Condition pattern of patina on Neptunbrunnen, bronze sculpture with patina by stroke, Berlin, Germany
Damage pattern, depression due to repeated abrasion effect of feet, Pfarrkirche Tschars, South Tyrol, Italy
Damage pattern, depression due to repeated abrasion effect of feet, Pfarrkirche Tschars, South Tyrol, Italy

Inappropriate interventions

Inappropriate repair

Cause of Damage:

  • Incompatible techniques and materials,
  • Material characteristics
Definition / Description:

Inappropriate and incompatible techniques or materials for repair that may damage the original materials, such as the use of Portland cement or iron dowels.

Note: this is not a damage phenomenon in the strict sense, but an important cause of various related consequential phenomena

Condition Class:

minor symptoms
to moderate symptoms

CC1 CC2

Urgency Class:

intermediate term (1-3 years)

UC1

Damage pattern of inappropriate repair on sandstone with stone replacement mortar, Einbeck, Germany
Damage pattern of inappropriate repair on sandstone with stone replacement mortar, Einbeck, Germany
Damage pattern, use of incompatible material, sandstone with cement mortar joints, Cordoba, Spain
Damage pattern, use of incompatible material, sandstone with cement mortar joints, Cordoba, Spain
Damage pattern of inappropriate intervention, Kaiser-Wilhelm-Gedächtniskirche (War Memorial Church), Berlin, Germany
Damage pattern of inappropriate intervention, Kaiser-Wilhelm-Gedächtniskirche (War Memorial Church), Berlin, Germany

Annex

Classification of Condition

The classification is based on the „European Norm for the Conservation of cultural property — Condition survey and report of built cultural heritage (EN 16096:2012)“

Refer to “Guideline Integrated Building Documentation

Condition Classification (CC = condition class)

For each component / building element a condition class shall be stated.
The condition classification is based on an overall assessment of all the relevant symptoms.

No Symptoms

Apparently without perceptible change in substance

CC0

Minor Symptoms

Only superficially, without substantial changes
(loss < 20%)

CC1

Moderate Symptoms

Locally limited damage / loss of surface
(loss < 50%)

CC2

Major Symptoms

Serious damage, severe substantial loss / danger of collapse
(loss > 50%)

CC3

Total Loss

Physically complete destruction of a building / component / element (loss > 90%)

CC4

Risk classification (UC = urgency class)

A risk assessment for each component (or collectively for multiple components exhibiting similar symptoms) shall be performed.
The urgencies expressed through the risk analysis is graded into categories of urgency.

Without need for action

 UC-

Long term

from 3 years

UC0

Intermediate term

1 – 3 years

UC1

Short term

within 1 year

UC2

Urgent and immediate

within 3 month

UC3

Overall classification (RC = recommendation class)

An overall recommendation class for the built cultural heritage as a whole shall be specified based on the risk assessment and recommended measures of all the components.
It is specified by evaluating each component, its condition and risk. graded into categories of urgency.

No Recommendation Class assigned

 RC-

No measures

RC0

Maintenance / Preventive conservation

RC1

Moderate repair and/or further investigation

additional investigations or expert opinions may be necessary

RC2

Major intervention based on diagnosis

RC3

Rebuilding / Reconstruction / Archeological Presentation, …

RC4

Glossary

of surface and material condition phenomena

The classification is related to the „ICOMOS illustrated glossary on stone deterioration patterns, Monuments and Sites XV, 2008 (Link)“

Cracks and Deformation Detachments | Biological colonization | Material losses | Discoloration / Deposit | Human intervention

  1. Cracks and Deformation
Catalogue of Damage - Architectural Heritage
Catalogue of Damage - Architectural Heritage
  • Cracks
  • Cracks of construction
  • Deformation
  • Structural crack / Settling crack
  • Masonry cracks
  • Design and construction cracks
  • Incompatibility cracks
  • Wall bulging
  • Wall swelling
  • Fracture
  • Star crack
  • Shrinkage / hairline crack
  • Craquelee

Cracks and Deformation Detachments Biological colonization | Material losses | Discoloration / Deposit | Human intervention

  1. Detachments
Catalogue of Damage - Architectural Heritage
  • Blistering
  • Bursting
  • Delamination
  • Exfoliation
  • Disintegration
  • Crumbling
  • Sanding
  • Fragmentation
  • Peeling
  • Scaling
  • Flacking
  • Spalling/ Contour scaling

Cracks and Deformation | Detachments Biological colonization Material losses | Discoloration / Deposit | Human intervention

  1. Biological colonization
Catalogue of Damage - Architectural Heritage
  • Alga
  • Lichen
  • Moss
  • Mould
  • Plants
  • Roots
  • Insects
  • Microbes