“After identifying the materials, the next step is to find out how the building was constructed [and why it was constructed]…This is not always easy because it may be concealed or covered by other materials [and influences].”
Conway & Roenisch 2005
A building’s structure may be likened to a human skeleton – offering a framework on which to hang soft tissue or cladding – without the skeleton or structural frame the cladding or soft tissue would be without form. But one without the other equally has no identity. The human analogy might be extended to encompass spiritual value in that the human form relies not only on physical presence but also on an emotional and spiritual component to establish identity. Thus the physical presence and cultural significance of an asset are also symbiotically entwined.
Basically there may be two identifiable types of construction:
- Load-bearing walls
- Frame construction
There may be a third form - membrane structures
Within these basic categores there may be many variations of type and form.
Identify examples in your locality of the two main constructional forms referred to above
Using the examples you have identified in the question above: identify patterns of deterioration typical in both
Identify a 21st-century membrane structure and why your chosen structure has significance
You should be able to demonstrate a sound knowledge and understanding of the various forms and types of construction together with an ability to provide advice on best methods of interventive repair having minimal effect on the original asset and its cultural significance. Your expertise in this area relies on three elements of skill:
- Diagnostic skills and,
- Prognostic skills and based on both these,
- Ability to make remedial recommendations
You should be able to demonstrate all three skills listed above.
Patterns of deterioration may be complex and have multiple causes and sources. How this interplay or interaction of symptoms and causes is enmeshed needs to be unraveled and analysed by your investigative skills.
Knowledge of how an asset is constructed and how this may be contributing to the causes of decay is a vital skill for you as a conservation practitioner. You must be able to demonstrate a sound knowledge of constructional forms and methods. Where your knowledge is lacking you should either seek specialist advice or seek to improve your knowledge by research and study.
Similar principles to those defined in the previous section (Materials) apply equally to this section, and you should be able to demonstrate familiarity with and understanding of the principles of decay in construction and failure of and identification of failures in structure, fabric, materials and weatherproofing. This knowledge should encompass all elements of construction including walls, roof, floors, foundations etc together with secondary elements of construction such as windows, doors, finishes, etc.
You should be able to identify forms and methods of construction not only in respect of the ancient built environment but also in respect of more contemporary methods of construction such as the use of concrete (in all its forms), steel structures, etc. After all, conservation of assets is not limited to the centuries preceding the present one.
- The Crystal Palace for the Great Exhibition of 1851
- The Seagram Building, New York 1954
- A log cabin
- The Millennium Dome
- Other examples from the web site below
- The building in which you are reading this text
See also: The Great Buildings Collection
In early history, constructional forms were limited to adoption and use of locally available materials and constructional methods.
Identify a Neolithic monument where this last statement may not apply. Consider why the choice of materials in the identified site might have been chosen for reasons other than local convenience.
As time passed use of local materials and methods were subject to external influences as travel beyond local boundaries was facilitated by better communication and methods of transport. One of the most influential periods of development in England was possibly during the Roman occupation when international influence altered English culture most fundamentally. This was adversely affected during the period known as the Dark Ages when British culture slipped into decline – void of enlightened external influence. The most prolific period of early constructional expansion in Britain was during the Norman Conquest when international influence again established itself. Probably the most stylistic period of influence was during the Renaissance, again when international influences affected British culture. The most explosive development period was during, and immediately post, the Industrial Revolution, when transportation, communication and availability of mass produced materials expanded exponentially and when British culture was, perhaps, influential rather than subject to influence.
Knowledge of these simple facts of history may help us to identify influence and understand development in constructional forms.
Consider a building you know well (your home, your office, your local town hall etc). List all the materials that have been used in it and identify which ones were produced locally and which were transported from afar. Of those produced locally, how many are still available from local sources.
Technological advance probably followed a parallel pattern and much of our built heritage was affected by technological change for similar reasons of influence.
Consider the historical development of the way timber has been used in building structures. Attempt to identify buildings in you own area which show the four stages identified by Ross as (i) medieval framing, (ii) 17th – 18th century masonry buildings with timber roofs and floors, (iii) 19th century industrialised with iron components linking timber members, and (iv) 20th century engineered timber frame components.
Ross, P (2002) Appraisal and Repair of Timber Structures Thomas Telford, London
What defects are possible/likely in the four stages mentioned above by Ross?
An understanding of these patterns of influence is essential data when formulating an understanding of the factors affecting why an asset is like it is and valued for it.
This might be a fundamental tenet when trying to understand the factors affecting cultural significance and why the historical environment was formed in the way that it was/is.
Let us not forget factors of influence that are purely social: religious, societal and based on human need; all are factors of influence that we must be aware of when analysing an asset, its reasons for being and how and why it was constructed in the way that it was.
Constructional development is a continuum – interfere with it, without understanding, at your peril; recognise that there is a need to influence that continuum but only by appropriate intervention, recognising what has gone before and, what might follow.
As construction technology has evolved over the centuries, innovative designers have stretched the boundaries of the use of available materials, often exposing them to conditions that they have subsequently been unable to tolerate, with resulting deterioration.
Consider some examples of early, innovative (and therefore historically significant) uses of materials that have, or may, posed significant challenges to those responsible for conserving them.
Useful web sites:
“Without change there would be no history…"
Cossons, Sir N.