Time demands of traditional hand-hewing techniques for sustainable repair of wooden heritage structures: A comparative study

Abstract

The hand-hewing of timber has been a fundamental skill for carpenters throughout history. Inevitably though, the majority of wood used in construction at the present time is processed with the use of machines. Repairing heritage objects with machined wood however, as opposed to working replacement timber using similar craft methods and tools as those used in the original, is often in conflict with the principles set forth in the Venice Charter for the Conservation and Restoration of Monuments and Sites. Ultimately, relying on mechanization is a missed opportunity to contribute to the preservation of valued intangible cultural heritage.Whereas the sustainability of traditional woodworking techniques and technologies can be promoted by applying them in the conservation of historical wooden buildings, the labor-intensive and time-consuming nature of manual woodworking makes feasibility questionable. In order to provide valuable insight for planners and monument care workers, the paper presents a study on the time demands associated with processing hand-hewn beams intended for use in the structural repair of wooden heritage objects.A series of experiments was conducted wherein a total of 94 beams 18×22 cm in profile and 2.5 m in length were hewn from spruce logs of various diameters. The relationship between initial log diameter and required processing time is presented as a linear function. The relative proportions of the individual steps to the hewing process as a whole were also documented and showed a clear dependency on the total amount of material removal required. The overall processing time was significantly reduced in the case of timber that was soaked for several months before being hewn into beams, and the low-work hewing technique was shown to be more efficient in comparison to high work on trestles.This paper has been published in memory of Petr Růžička, the great pioneer of forgotten carpentry techniques whose work opened a window to our past for future generations.