Natural Durability of Timber Exposed Above Ground – a Survey

Brischke, Christian; Meyer, Linda; Alfredsen, Gry; Humar, Miha; Francis, Lesley; Flæte, Per-Otto; Larsson-Brelid, Pia

doi:10.5552/drind.2013.1221

Cited by 37 publications

(26 citation statements)

References 12 publications

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“…In the second year, the first signs of decay developed on Norway spruce (PA), beech (FS) and Scots pine sapwood (PS). This is in line with findings from previous studies [13,51]. One of the possible reasons for the lesser decay of Scots pine sapwood could be associated with pinosylvin.…”

Section: Decay Rate In the Decking Of The Model Housesupporting

confidence: 93%

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

Humar

Kržišnik

Lesar

et al. 2019

Forests

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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.

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Section: Decay Rate In the Decking Of The Model Housesupporting

confidence: 93%

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

Humar

Kržišnik

Lesar

et al. 2019

Forests

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“…was between 0.16 (teak) and 1.35 (alder) among the hardwoods and between 0.32 (juniper) and 1.14 (silver fir) among the softwoods. The wider range in biological durability of hardwood species compared to softwoods is consistent with previous reports [15,89].…”

Section: Untreated Timbersupporting

confidence: 92%

“…Furthermore, results of above-ground tests performed at different locations worldwide were obtained in horizontal lap-joint tests [45,69,86], sandwich tests [16], decking tests [19], deck tests [63,81], close-to-ground mini-stake tests [79], multiple layer tests [15], block tests [79][80][81], vertically hanging stakes [57], painted and unpainted L-joint tests [15,87], horizontal double layer tests [57], and modified horizontal double layer tests [68].…”

Section: Test Methods For Determining the Modifying Factors K Inh And K Wamentioning

confidence: 99%

“…Occasionally, this is called "torture testing" [14] since it does not necessarily reflect the anticipated use conditions. Above-ground field tests deliver durability data under quite realistic hazard conditions, but respective test data are sparsely available [15]. Numerous above-ground test methods have been reported, but very few are standardized [16].…”

Section: Introductionmentioning

confidence: 99%

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Modelling the Material Resistance of Wood—Part 2: Validation and Optimization of the Meyer-Veltrup Model

Brischke

Alfredsen

Humar

et al. 2021

Forests

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Service life planning with timber requires reliable models for quantifying the effects of exposure-related parameters and the material-inherent resistance of wood against biotic agents. The Meyer-Veltrup model was the first attempt to account for inherent protective properties and the wetting ability of wood to quantify resistance of wood in a quantitative manner. Based on test data on brown, white, and soft rot as well as moisture dynamics, the decay rates of different untreated wood species were predicted relative to the reference species of Norway spruce (Picea abies). The present study aimed to validate and optimize the resistance model for a wider range of wood species including very durable species, thermally and chemically modified wood, and preservative treated wood. The general model structure was shown to also be suitable for highly durable materials, but previously defined maximum thresholds had to be adjusted (i.e., maximum values of factors accounting for wetting ability and inherent protective properties) to 18 instead of 5 compared to Norway spruce. As expected, both the enlarged span in durability and the use of numerous and partly very divergent data sources (i.e., test methods, test locations, and types of data presentation) led to a decrease in the predictive power of the model compared to the original. In addition to the need to enlarge the database quantity and improve its quality, in particular for treated wood, it might be advantageous to use separate models for untreated and treated wood as long as the effect of additional impact variables (e.g., treatment quality) can be accounted for. Nevertheless, the adapted Meyer-Veltrup model will serve as an instrument to quantify material resistance for a wide range of wood-based materials as an input for comprehensive service life prediction software.

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“…Important use of ayous wood is for realizing outdoor covering of the buildings, especially in northern and central Europe. Outdoor uses expose wood to the main degradation agents such as UV, moisture and biological attacks [4,5]; and ayous wood is a low durable wood. To improve the durability of material preservatives are generally needed, which can limit the effects caused by wood degradation agents.…”

Section: Introductionmentioning

confidence: 99%

Modifications of Physical and Mechanical Characteristics Induced by Heat Treatment: Case Study on Ayous Wood (Triplochiton scleroxylon K. Schum)

Gennari

Picchio

Tocci

et al. 2020

The 1st International Electronic Conference on Forests—Forests for a Better Future: Sustainability, Innovation, Inter

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Wood is a material of biological origin of fundamental importance for artisan and industrial uses. In outdoor environments, it is very attractive, but easily subjected to degradation. A valid alternative to chemical preservatives is thermal modification. The aim of this study is to evaluate ayous wood industrially subjected to thermal modification (215 °C) in order to emphasize the influence of heat treatment on selected physical and mechanical characteristics. As a result of the heat treatment, the physical and mechanical properties are generally reduced: the density in natural wood (TQ) was 379 kg/m3, in heat treated wood (TT) 319 kg/m3; the basic density in TQ was 327 kg/m3, in TT 299 kg/m3; the axial compression strength of TT was reduced by 18.1%; and the static bending strength of TT was reduced by 41.4% compared to untreated wood at 10% equilibrium moisture content (EMC). In addition, the samples, under the same environmental conditions in the laboratory, reached the equilibrium moisture content of 10% in TQ and 4% in TT.

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Natural Durability of Timber Exposed Above Ground – a Survey

Cited by 37 publications

References 12 publications

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

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

Modelling the Material Resistance of Wood—Part 2: Validation and Optimization of the Meyer-Veltrup Model

Modifications of Physical and Mechanical Characteristics Induced by Heat Treatment: Case Study on Ayous Wood (Triplochiton scleroxylon K. Schum)

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