A Visual Assessment of Cross-laminated Timber Structures in Austria

Cross-laminated timber (CLT) construction systems have been used commercially for over 20 years, mainly in Western Europe and North America. However, there has not been a report on the current status of CLT buildings. Deterioration of wooden buildings could result from a variety of causes, and the life of the structures could be extended if periodic inspections were conducted. This research introduces a visual inspection methodology for assessing deterioration of CLT structures. The inspection methodology was tested in six CLT buildings in Austria. The methodology was proven to be effective in determining the current internal and external condition of the examined CLT structures. The oldest CLT structure inspected dates from 2004. The newest structure inspected was still under construction. The results of the application of the visual inspecting tool show that there was very little damage to the CLT structures. Visual inspections cannot always find damage to structural members, but it is an accepted inspection methodology to discover potential causes or more severe damage. The main causes of damage came from exposure to water on the exterior of the buildings and poor control of humidity and temperature in indoor conditions. Architects who designed the inspected buildings were interviewed to cross validate the results of the visual inspection methodology. In addition, the interviews provided important insights related to the design, construction, and current conditions of the buildings. Furthermore, the architects also provided information regarding the main barriers and drivers that affect CLT construction in Austria.