Guidelines for the on-site assessment of historic timber structures

In the scope of COST IE0601-WoodCulther (http://www.woodculther.org) it was agreed to produce Guidelines for the Assessment of Historic Timber Structures, covering the principles and possible approaches for the safety assessment of old timber structures of historical relevance, that could be used as the basis for possible European Standards, as discussed with CEN/TC346 (Conservation of cultural heritage). This was targeted at all those concerned with the conservation of heritage buildings. It should also help decision-making regarding the need for immediate safety measures. Its aim is to guarantee that inspection and assessment measures provide the necessary data for historical analysis, structural safety assessment and planning of intervention works, while having minimal impact on the building fabric (the original materials, structural systems and techniques). This paper provides information on the criteria to be used in the assessment of load bearing timber structures in heritage buildings. It covers the preliminary assessment (desk survey, preliminary visual survey, measured survey, structural analysis and preliminary report), as well as the detailed survey of timbers (with a special emphasis on visual strength grading on site) and carpentry joints. The subsequent diagnostic report and the detailed design of repairs are outside its scope.
This paper originates from a document with the same name prepared by the Task Group “Assessment of Timber Structures” set within COST Action IE0601 – Wood Science for Conservation of Cultural Heritage (WoodCultHer) and presented to its final meeting in November 2011. Therefore, the authors thank to COST for sponsoring two Task Group meetings, CIS-Madeira (SP) and LNEC (P) for hosting them and Dr. Philipe Galimard, Dr. Emmanuel Maurin, Dr. Ladislav Reinprecht and Dr. Artur Feio for their suggestions. They also acknowledge the work done by all the Committees working on the same subject in the past, namely ICOMOS/ISCARSAH, CIB/Commission W023, CEN/TC250, ISO/TC98, UNI - CT Normal - GL20 and COST Action E55, which produced the valuable standards, guidelines and other background documents referenced in the text and listed under Bibliography.