C O N T E X T 1 3 4 : M A Y 2 0 1 4 13 ROBERT DEMAUS Timber conservation and repair Genuinely traditional repairs (which generally fit the principle of ‘repair by addition’ rather than ‘repair by replacement’) often result in retaining more of a building’s historic fabric. Timber is probably the oldest, and certainly the most ubiquitous, building material. In the Elizabethan timber-framed manor house, its use is plain to see, but the Georgian brick terrace and medieval stone cathedral also contain significant amounts of structural and decorative timber. Almost every building of historic significance will contain some structurally significant timber. The main enemies of historic timber within the built environment are water, humans and, very occasionally, fire. If kept reasonably dry, timber will last indefinitely. Only when it is allowed to remain damp for a considerable time, usually due to lack of maintenance and/or the use of unsuitable materials, does it become vulnerable to degradation. Perhaps inevitably, the depredations of human activity and the (often consequent) degradation by fungi and beetles result in the need for repairs. It was ever thus, but over the last century we have become increasingly conscious of the need to conserve what we see as our cultural and material heritage. In theory the way in which we now repair our buildings should put greater emphasis on the retention and conservation of the existing historic fabric, rather than its replacement with new material. To this end, a series of guiding principles identifying best practice has evolved. In the context of timber repairs these are: 1. Any repair should be the minimum necessary to These wrought-iron straps and bolts are probably early 17th-century (and therefore historically important in their own right) repairs to an ornate late 14th-century church roof.The metal has not been painted or galvanised (and is not stainless steel) but it has survived happily (and over time toned down very well) for 400 years.Very little of the important carved work has been lost in the process. return the structure to a state in which it is fit for purpose, and in which the risk of further degradation is minimised. 2. As much as possible of the original or surviving timber should be retained, and repairs should be designed to achieve this. 3. Intervention into, and disturbance of, the surrounding fabric of the structure should be kept to the absolute minimum necessary to achieve a satisfactory repair. 4. The repairs carried out should if possible be reversible and, at the very least, should not hinder subsequent repairs should they prove necessary. 5. Where possible, the reason for the intervention should remain apparent after the repair is completed. Although rarely discussed in charters and guidance, costs must be taken into consideration. Repairs need to be economic and proportional to the historic significance, not just of the building, but of the specific element. In an ideal world, decisions about the most conservative and appropriate way to repair a building should not be influenced by issues of cost. However, in almost every project there is a finite sum that can be spent, and there is often a compromise to be achieved, where costs saved in one area of work can be directed to other areas, where expenditure may prove more beneficial overall. To ignore the financial implications of different approaches to repair, or to pretend that they are not an important factor in the
RkJQdWJsaXNoZXIy MjgyMjA=