Purpose: Quality failures in the design and construction process can entail significant delays and costs. Databases of building defects have proven to be useful for drawing conclusions on underlying causes of building defects and for identifying potential improvement actions to reduce the occurrence of building defects.Design/methodology/approach: The database comprising 27,074 cases from a Belgian insurance company was studied, and it was found that moisture problems account for 48% of all building defects, and stability problems 23%. To better analyse the geographical variability, the data were enriched with demographical, geographical and climatological factors of the municipality the concerned buildings were located in. This combined information was used to determine underlying external factors that impact the probability that specific types of building defects occur.Findings: The analysis of the data shows that external factors do indeed have a statistically significant impact. The factor with the highest impact is the number of walls the building has in common with its neighbours. The most significant climatological factor is the wind speed.Originality/value: A better understanding of the frequency of building defects and factors that contribute to the likelihood are important variables to consider in quality control and prevention.

This study examines decay risks in cross-laminated timber (CLT) wall assemblies with built-in moisture, aiming to develop a simulation-based methodology to assess moisture dynamics during the construction phase. Differing from previous research, this study focuses on the central regions of CLT wall panels. Moisture distribution within the panel, especially in the exposed layer, is critical for understanding potential degradation. A series of simulations were conducted to determine the necessary level of detail for moisture profiling, comparing approaches that use a single average value, layer-specific averages, and a refined profile that distinguishes the outer 5 mm from the remaining material. The influence of factors such as wood type, glue type, delivery moisture content, orientation, and rain exposure was systematically evaluated to define realistic moisture profiles at the end of the construction phase. Subsequent degradation assessments incorporated these profiles along with variations in insulation materials to evaluate the time of wetness, dose accumulation, and heat flux increases. Results indicate that a detailed moisture profile is essential for accurately predicting decay risk and that trade-offs exist between moisture management and thermal performance depending on the insulation used. These findings provide a framework for predicting decay risks in CLT assemblies and offer insights for designing more durable and energy-efficient structures.

In Europe, 40% of the total energy requirements relates to the energy consumption in the construction sector. The awareness resulted in the use of bio-based materials thanks to their small carbon footprint (Zhao et al. 2017). The aim of this study is twofold. The first objective is to gain a better understanding of the durability of traditional insulation materials such as mineral wool and PUR versus bio-based insulation (cellulose) in timber frame constructions and CLT constructions. The second objective is to evaluate to which extent this durability depends on various levels of climate change impact we might face based on the future greenhouse gas concentrations. This study uses the Mould Index as an indicator for possible degradation of the insulation layer. The mould Index is calculated using temperature and relative humidity derived from HAM simulations in Delphin 6.1.4. These simulations are done for different wall assemblies and different climate scenarios for Brussels. The results show that climate change has a negative effect on the durability of the outer part of the insulation material and that this effect is higher for cellulose than for mineral wool in timber frame construction.