Structural Failures and States of Preservation
future deterioration is to use it. Its continued utilisation, even if for a new purpose, will pose a need for regular upkeep which should in turn discourage neglect. The alteration or extension of a building structure for its adaptive reuse requires a degree of spatial flexibility which earthen construction has, given its informal and plastic nature. If reuse builds upon these intrinsic characteristics earthen structures are able to meet the requirements and standards of present-day uses without losing their essential qualities. With reference to the degrees of preservation of the settlement, conservation strategies will have to meet the following: • structures in “adequate” state of preservation: refurbishment alterations will be carried out in a way that respects he scale, massing, form, materials and the social status of the structure as well as the architectural composition and skyline of the cluster to which it belongs (no new construction, demolition or modification which would alter the relations of mass and colour must be allowed according to art. 6 of the Venice Charter, 1964); • structures in “adequate”, “acceptable” and “inadequate” states of preservation: the original fabric will be retained as much as possible to be consolidated, renewed and refurbished; • structures in “acceptable” and “inadequate” states of preservation: missing elements – walls, floors, ceilings, staircases – will be replaced with new elements clearly distinguishable by material, form, grain, construction or texture from the original structure. Replacements of missing parts must integrate harmoniously with the whole, but at the same time must be distinguishable from the original so that restoration does not falsify the artistic or historic evidence (Art. 12 of the Venice Charter, 1964). Any extra work which is indispensable must be distinct from the architectural composition and must bear a contemporary stamp (art. 9 of the Venice Charter, 1964); • structures in “inadequate” and “ruinous” states of preservation: consolidation will be carried out by employing the most suitable available technologies at the time of intervention (where traditional materials prove inadequate, the consolidation of a monument can be achieved by the use of any modern technique for conservation and construction, the efficacy of which has been shown by scientific data and roved by experience, art. 10 of The Venice Charter, 1964).
4.3 GUIDING PRINCIPLES TO REPAIR ACTIONS The following methodological criteria must be met in implementing the general repair measures: • repair must be necessary, reversible, the minimum required to achieve the proposed result and
compatible with the original fabric; • repair must be preceded by investigation of the reason for failure, so that recurring failure can be prevented by appropriately dealing with the causes of damage and making good effectively; • repair must be preceded by investigation into construction aspects - soil content, clay type, pH value, lime/clay composition in mortar and plaster, strength of materials - climate aspects - relative humidity and temperature both inside and outside the building units - environmental aspects - thermal conductivity of walls and temperature of floors - use aspects - changes made to the structure which might have caused failure; • repair must take into account the results of recording and documentation in terms of historical background, social status, spatial organization and construction of the structures; • repair must take into account social, cultural and economic driving factors such as the need for local employment, maintenance of tradition and training; • repair must achieve a balance between the materials required for the intervention and the requirements of tradition; • repair must be fully documented and archived throughout works.
GUIDANCE NOTES
1. For the purpose of having an as accurate as possible mapping of failure types, these have been identified only in building units documented both graphically and photographically, that have maintained their original fabric unaltered (“old buildings”) or have been modernized to a little extent (“modernized old buildings”). Under these circumstances the total number of mapped units is 81. 2. Only failure types that were clearly distinguishable and unequivocally classifiable have been included in the analysis and mapping. 3. Presumably all building units underwent a stage where each relevant failure type occurred, even though currently there is no clear evidence of it.
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