Changes in moisture performance of wood after weathering

Kržišnik

Lesar

et al. 2019

Forests

Self Cite

Wood is one of the most important construction materials, and its use in building applications has increased in recent decades. In order to enable even more extensive and reliable use of wood, we need to understand the factors affecting wood’s service life. A new concept for characterizing the durability of wood-based materials and for predicting the service life of wood has recently been proposed, based on material-inherent protective properties, moisture performance, and the climate- and design-induced exposure dose of wooden structures. This approach was validated on the decking of a model house in Ljubljana that was constructed in October 2013. The decay and moisture content of decking elements were regularly monitored. In addition, the resistance dose DRd, as the product of the critical dose Dcrit, and two factors taking into account the wetting ability of wood (kwa) and its inherent durability (kinh), were determined in the laboratory. DRd correlated well with the decay rates of the decking of the model house. Furthermore, the positive effect of thermal modification and water-repellent treatments on the outdoor performance of the examined materials was evident, as well as the synergistic effects between moisture performance and inherent durability.

Section: Moisture Performance Of Deckingsupporting

confidence: 76%

Section: Moisture Performance Of Deckingmentioning

confidence: 84%

The Performance of Wood Decking after Five Years of Exposure: Verification of the Combined Effect of Wetting Ability and Durability

Kržišnik

Lesar

et al. 2019

Forests

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“…(2) MC was determined through measurements of electrical resistance (Table 1). Insulated electrodes (stainless steel screws) were applied 5 mm below the surface of the wooden planks at various positions and linked to electrical resistance measuring devices Gigamodule (Scanntronik Mugrauer GmbH, Germany) ( Figure 2) [17]. All measurements were performed on the south-facing façade, as this façade is more exposed to weathering.…”

Section: Methodsmentioning

confidence: 99%

“…It is therefore of great importance to develop a methodology for the fastest assessment of the performance of wood and wood-based materials in less exposed applications. Published studies have indicated that moisture performance field tests may serve as a time-saving alternative to long-term decay tests in the field [4,16,17]. This approach is supported by a model approach that defines material resistance based on the combined effect of wetting ability and durability [18].…”

Section: Introductionmentioning

confidence: 99%

Moisture Performance of Façade Elements Made of Thermally Modified Norway Spruce Wood

Lesar

Kržišnik

2020

Forests

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Wooden façades are gaining in importance. Thermally modified wood is becoming one of the preferred materials for claddings. In spite of the fact that façades made of thermally modified wood have been in use for more than two decades, reports about long-term monitoring have been sparse. The results of three-year monitoring of a façade made of thermally modified wood in Ljubljana are reported. Moisture content measurements of thermally modified façades were taken at 22 locations and compared to the moisture content of untreated Norway spruce wood. Temperature and relative humidity were recorded in parallel. The moisture content of the wood was compared to the average relative humidity before the measurements. The results confirm the lower moisture content of thermally modified wood in comparison to reference Norway spruce. The moisture content of the wooden façade could be best correlated with the average relative humidity and temperature 48 h before the wood moisture content measurement was taken.

“…To nenazadnje dokazujejo tudi številne objave (npr. : Humar et al, 2015;Brischke & Meyer-Veltrup, 2016;Žlahtič Zupanc et al, 2018;Kržišnik et al, , 2018. Povprečna vlažnost lesenih eksponatov v bunkerju se je gibala med 21 % in 54 % (Preglednica 2).…”

Section: Rezultati In Razprava Results and Discussionunclassified

Evaluation of the wood degradation in the underground fort Goli vrh

Lesar²,

Žagar³

et al. 2019

les-wood

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Izvleček / AbstractIzvleček: Pred drugo svetovno vojno so v okolici Golega vrha postavili obsežno podzemno utrdbo. Še od časa izgradnje je v utrdbi ostalo nekaj lesa, dodatno so pred leti namestili nekaj lesenih razstavnih predmetov. Na lesu je bilo nekaj let po odprtju opaziti obsežen glivni razkroj. V utrdbi smo namestili senzor za spremljanje relativne zračne vlažnosti in temperature, izolirali nekaj vzorcev lesa in jih preiskali z rentgensko fluorescenčno spektroskopijo in lasersko konfokalno vrstično mikroskopijo. Analiza je potrdila visoko vlažnost lesa in prisotnost gliv razkrojevalk na vseh lesenih eksponatih z izjemo lesenih zabojnikov za strelivo.Abstract: Before the Second World War, a large underground fortress was built around Goli vrh. Some wood remains in the fort from the time of construction, and some wooden objects have been exhibited in the fort. Several years after the opening of the fort, large scale decomposition was observed on the wood. A sensor for monitoring the relative air humidity and temperature was installed. In addition, a few samples of wood were isolated and examined by X-ray fluorescence spectroscopy and laser confocal linear microscopy. The analysis confirmed the high humidity of the wood and the presence of wood decay fungi on all wood objects, with the exception of wooden ammunition boxes.