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Analysis of wooden shingles after seven years of exposure
2022 - IRG/WP 22-20690
Wood is a traditional roofing material in the Alpine regions. In the 17th century, wooden roofing was typically used on more important buildings. Still, today it is predominately used on huts and houses in the hilly regions of northern and north-western Slovenia. Because wooden roofing is expensive, we investigated the possibility of extending the service life of the roofing through impregnation a...
M Humar, B Lesar, D Kržišnik, E Keržič, B Jemec


Properties of Iron (II) Sulphate treated Norway Spruce
2022 - IRG/WP 22-30765
Exterior wood is exposed to various environmental factors that cause weathering. Weathering is important primarily from an aesthetic standpoint. However, not all parts of the building are equally susceptible to weathering. Parts exposed to moisture will discolour faster than protected parts, such as wood under roof overhangs. To achieve fast and uniform artificial greying, a surface treatment with...
B Lesar, M Humar, M Škamlec


Assessment of the Material Durability and Structural Integrity of the Wooden Velodrome in Češča vas, Slovenia
2023 - IRG/WP 23-11012
Wood is a widely used material in the construction industry, and it has been utilized for thousands of years to create buildings and other structures. When wooden structures are designed, built, and maintained properly, they can be safe and long-lasting. Sports facilities, which provide athletes with a space to train, compete, and improve their abilities, are crucial in creating a strong and susta...
D Kržišnik, M Humar, B Lesar


Moisture performance of wooden shingles tested on the Golobar cable yarding
2023 - IRG/WP 23-20704
Wood is a traditional roofing material in Europe and other parts of the world. In the 17th century, wooden roofing was generally used on more important buildings, but today it is mainly used on huts and houses in the Alpine regions. As wooden roofing is expensive, we investigated the possibility of extending the service life of the roofing through material selection and details. The roof of the Go...
M Humar, B Lesar, D Kržišnik


Reuse of discarded wood and alternative wood species to replace spruce in the development of wooden windows for complete disassembly – REWINNUSE
2023 - IRG/WP 23-30785
The REWINNUSE project focuses on the reuse of discarded wood and alternative wood species and on the development of wooden windows that can be easily disassembled into their basic components. In cooperation with the project partners (M Sora, the University of Ljubljana Biotechnical Faculty (BF), the Norwegian Institute of Bioeconomy - NIBIO and the Slovenian Forestry Institute (GIS)), the project ...
B Lesar, M Humar, J Levanič, A Treu, A Ugovšek, L Kramarič, B Štrakel, L Križnar, B Šubic, J Gričar


Influence of weathering of wood surfaces before and after treatment with iron(II) sulphate
2023 - IRG/WP 23-30786
Outdoor wood is exposed to various factors that cause the wood to grey or age. The ageing processes can vary greatly depending on the exposure. Parts of the wood that are not exposed to external factors, e.g. under the eaves, are less exposed and the ageing process is therefore slower. This can be accelerated by solutions based on iron ions. In this way, the wood greys quickly and evenly. However,...
B Lesar, M Humar, F Osvald


Assessment of the condition of wooden mill in the area of Kovačevići in Bosnia and Herzegovina
2023 - IRG/WP 23-11030
An excellent example of cultural and technical heritage is almost 100 year old wooden mills near Cazin in Bosnia and Herzegovina. These mills played an important role, especially in times of Bosnian war (1992-95), when this region was cut off from electricity. The laboratory analysis revealed that the respective mill was made of chestnut (Castanea sativa) and oak (Quercus sp.) wood. The sufficient...
B Lesar, R Hasanagic, M Humar


Analysis and performance of spruce alternative species and discarded wood for windows production
2024 - IRG/WP 24-50386
Climate change is having a significant impact on European forestry, particularly on the softwood species used for window frames. This study investigates potential replacement tree species for spruce (Picea abies), the predominant material for window frames. We evaluate Douglas fir (Pseudotsuga menziesii), Scots pine (Pinus sylvestris), thermally modified poplar (Populus nigra) and discarded silver...
B Lesar, J Levanič, M Humar, A Treu


The durability and mechanical properties of 40 years old Black locust poles
2024 - IRG/WP 24-11042
This study investigates the durability and mechanical properties of 40-year-old black locust (Robinia pseudoacacia) poles harvested from a vineyard in Slovenia. Wood from these poles was compared to recently harvested black locust wood to determine possible reuse options. Visual inspection, hyperspectral imaging, and laboratory tests were conducted to assess decay, density, mechanical properties, ...
M Humar, J Malik, J Levanic, D Krzisnik, E Kerzic, B Lesar


Transmission poles - Analysis of causes of premature failure in Slovenia
2025 - IRG/WP 25-20745
The study focuses on analysing the causes of the premature collapse of wooden transmission poles in Slovenia, where there have been several cases of rapid fungal decomposition of poles despite the planned lifespan of 30 to 50 years. The poles were made of Scots pine wood and impregnated with a copper-ethanolamine wood preservative. The research aimed to assess the condition of standing poles and e...
M Humar, B Lesar, N Kregar, S Drnovšek


Enhancing Wood Greying: A Study of Pre-Treatments and Iron(II) Sulphate Application
2025 - IRG/WP 25-41018
Recent trends in architecture and environmental policies have increased the demand for natural, unprotected wood in outdoor applications. However, wood exposed to the elements tends to grey unevenly, which can be problematic for visually important applications like timber façades. One solution is artificial greying with iron ions, providing a uniform colour that later transitions to natural greyi...
B Lesar, M Humar, A Kordiš


Optimising properties of citric acid-sorbitol bonded particleboards with added ammonium dihydrogen phosphate as fire retardant
2025 - IRG/WP 25-41033
Due to the adverse health effects of formaldehyde-based adhesives and their fossil origin, there is an ongoing search for appropriate bio-based adhesives for particleboards. Although there are some possible solutions, their use in construction is limited partly due to their low moisture resistance and flammability. The latter can be improved by adding various fire retardants. A particleboard with ...
L Kopač, S Medved, B Lesar, M Humar


Hyperspectral imaging in qualitative and quantitative assessment of biocide treated timber
2025 - IRG/WP 25-50407
A hyperspectral camera operating in the shortwave infrared light range between 1000 – 2500 nm was used to collect spectral profiles of timber treated with different biocides and varying concentrations of a copper-ethanolamine based wood preservative. The spectra were analysed using statistical methods like principal component analysis, linear discriminant analysis, and partial least squares to a...
J Levanič, E Keržič, B Lesar, M Humar


Addressing Climate Challenges through the Valorisation of Calamity Wood in the Alps-Adriatic Region
2025 - IRG/WP 25-50416
The WoodInnovate project addresses pressing challenges facing the forest-wood value chain in the Alps-Adriatic region, which are intensifying due to climate change. Rising temperatures and frequent natural disasters are degrading wood quality and increasing pest outbreaks, particularly from bark beetles. These environmental shifts jeopardize forest ecosystems, reduce the economic viability of timb...
M Humar, E Keržič, B Lesar, J Gričar, B Likar, E Beltramini, S Silvestri


Analysis of A Wooden Structure Damaged in a Fire – The Wooden Granary at Zaprice, Kamnik
2025 - IRG/WP 25-41049
Zaprice Open-Air Museum in Kamnik, Slovenia, features several granaries dating to the early 19th century, forming part of the national Cultural Heritage Register (EID: 1-09881). One of the two-chamber wooden granaries, constructed in 1828, suffered significant fire damage in December 2024. The objective of this study was to evaluate the extent of the damage, assess the structural integrity, and id...
M Humar, B Lesar, L Kopač, A Žagar


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