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146 records – page 1 of 15.

Experimental investigation of hygrothermal behavior of wooden-frame house under real climate conditions

https://research.thinkwood.com/en/permalink/catalogue3338
Year of Publication
2023
Topic
Moisture
Author
Rahim, Mourad
Djedjig, Rabah
Wu, Dongxia
Bennacer, Rachid
Ganaoui, Mohammed EL
Organization
University of Lorraine
University of Paris-Saclay
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Topic
Moisture
Keywords
Hygrothermal Behavior
Heat and Mass Transfer
Bio-based Building Envelope
Research Status
Complete
Series
Energy and Built Environment
Summary
This paper deals with the experimental investigation of hygrothermal behavior of wooden-frame building envelope. The experiment was based on in-situ monitoring of a full size experimental monozone house built at the University of Lorraine. Variations in temperature and relative humidity inside and outside the envelope were logged simultaneously with local meteorological data. Results showed the high coupling between temperature and relative humidity variations within the envelope materials. An overall hygrothermal response of the wall highlighted an interesting hygrothermal dynamic behavior of the envelope which may contribute to mitigate variations of relative humidity inside the building. Nevertheless, relative humidity evolves within a range of values that can lead to mold growth at a certain position which may alter wooden envelope life.
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An Investigation of the Impact of Water on Certain of the Mechanical and Physical Properties of Laminated Veneer Lumber (LVL) as Used in Construction

https://research.thinkwood.com/en/permalink/catalogue3358
Year of Publication
2023
Topic
Moisture
Material
LVL (Laminated Veneer Lumber)
Author
Juciene, Milda
Dobilaite, Vaida
Albrektas, Darius
Organization
Kaunas University of Technology
Publisher
MDPI
Year of Publication
2023
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Moisture
Keywords
Strength
Water Rise Level
Water Absorption
Research Status
Complete
Series
Applied Sciences
Summary
Timber and timber products are renewable materials that, due to their durability and strength properties, meet the requirements of the construction industry, are widely used in buildings. An analysis of the scientific literature has shown that there is a lack of detailed research that fully investigates the influence of the rate of increase of the moisture content of the timber on the mechanical and, especially, the strength properties of the LVL panels. Upon immersion into water of the bottom of the specimen, the water starts rising quite quickly at the edge of the specimen, and the first six hours are the most critical. The levels of water rise inside the LVL specimen were less significant than at the edges. It was found that water significantly affects the bending strength of the panels, which, when the strength of the wet panel compared to the strength of the dry panel, decreases to 45% after one soak cycle and almost to 52% after two soak cycles. The tensile strength of the wet specimens is ~40% less than that of the dry specimens. The strength of the panels that were dried back to their initial state was found to be sufficient again, different from the initial strength only within the error limits; the strength properties of the building structure will not be affected.
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Dimensional behavior of nail-laminated timber-concrete composite caused by changes in ambient air, and correlation among temperature, relative humidity, and strain

https://research.thinkwood.com/en/permalink/catalogue3374
Year of Publication
2023
Topic
Moisture
Material
NLT (Nail-Laminated Timber)
Timber-Concrete Composite
Author
Hwang, Sung-Wook
Chung, Hyunwoo
Lee, Taekyeong
Ahm, Kyung-Sun
Pang, Sung-Jun
Kim, Ji Yong
Bang, Junsik
Jung, Minjung
Oh, Jung-Kwon
Kwak, Hyo Won
Yeo, Hwanmyeong
Organization
Seoul National University
Year of Publication
2023
Format
Journal Article
Material
NLT (Nail-Laminated Timber)
Timber-Concrete Composite
Topic
Moisture
Keywords
Correlation
Dimensional Change
Moisture Content
Monitoring
Research Status
Complete
Series
BioResources
Summary
A timber-concrete composite (TCC) slab composed of nail-laminated timber (NLT) and topping concrete (TC) was developed for flooring applications. The NLT was laminated alternately with lumber and plywood. To investigate the dimensional behavior of the TCC slab, the temperature, relative humidity (RH), and dimensional changes of the slab exposed to outdoor air were monitored for 205 days. Temperature change was directly transmitted to both components, and RH change was gradually transmitted to the NLT. Concrete pouring caused a sharp increase in NLT width, which was the laminating direction of the nails. This resulted from swelling of the wood because of the moisture in the concrete mixture and loosening of the nail lamination. The member composition for the nail-laminating system, fastener type, and concrete volume help to secure the dimensional stability of the NLT. Cracks in the TC caused width deformation, which was recovered by drying shrinkage of the TC. Correlation analysis among temperature, RH, and strain indicated that dimensional changes in NLT correlated strongly with RH, while those in TC correlated strongly with temperature. The correlation between longitudinal strain in the TC and strain in the three directions of the NLT was attributed to the notches designed for mechanical connection.
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Differential Material Movement in Tall Mass Timber Structures

https://research.thinkwood.com/en/permalink/catalogue2982
Year of Publication
2022
Topic
Moisture
Application
Wood Building Systems
Author
Racine, Josephine
Lumpkin, Bryce
McLain, Richard
Organization
Fast + Epp
WoodWorks
Year of Publication
2022
Format
Report
Application
Wood Building Systems
Topic
Moisture
Keywords
Column Movement
Vertical Movement
Creep
Settlement
Shrinkage
Crushing Perpendicular to Grain
Research Status
Complete
Summary
As the height of mass timber buildings continues to grow, a new set of design and detailing challenges arises, creating the need for new engineering solutions to achieve optimal building construction and performance. One necessary detailing consideration is vertical movement, which includes column shrinkage, joint settlement, and creep. The main concerns are the impact of deformations on vertical mechanical systems, exterior enclosures, and interior partitions, as well as differential vertical movement of timber framing systems relative to other building features such as concrete core walls and exterior façades.
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Experimental Verification of Thermal Insulation in Timber Framed Walls

https://research.thinkwood.com/en/permalink/catalogue3007
Year of Publication
2022
Topic
Moisture
Application
Walls
Author
Michálková, Daniela
Durica, Pavol
Organization
University of Zilina
Editor
Pavlik, Zbyšek
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Application
Walls
Topic
Moisture
Keywords
Timber Framed
Relative Humidity
Thermal Conductivity
Material Properties
Research Status
Complete
Series
Materials
Summary
Current environmental crisis calls for sustainable solutions in the building industry. One of the possible solutions is to incorporate timber-framed constructions into designs. Among other benefits, these structures are well established in many countries, originating in traditional building systems. This paper focuses on experimental timber-frame walls. Different wall assemblies vary in thermal insulation materials and their combinations. We investigated ten experimental wall structures that have been exposed to natural external boundary conditions since 2015. The emphasis was on their state in terms of visual deterioration, mass moisture content, and thermal conductivity coefficient. We detected several issues, including defects caused by inappropriate realization, causing local moisture increase. Material settlement in loose-fill thermal insulation was another issue. Concerning was a significant change in the thermal conductivity of wood fiber insulation, where the current value almost doubled in one case compared to the design value determined by the producer.
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The Dimensional Stability and Bonding Performance of Hybrid CLT Fabricated with Lumber and COSB

https://research.thinkwood.com/en/permalink/catalogue3195
Year of Publication
2022
Topic
Moisture
Application
Floors
Walls
Author
Liang, Zhijun
Chen, Guojun
Wang, Yi
Wang, Zhiqiang
Gong, Meng
Organization
Nanjing Forestry University
University of New Brunswick
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Application
Floors
Walls
Topic
Moisture
Keywords
Hybrid Cross Laminated Timber
Construction Oriented Strand Board
Dimensional Stability
Bonding Performace
Delamination
Research Status
Complete
Series
Buildings
Summary
The differences of physical and mechanical properties of different laminations, such as softwood, hardwood or other structural composite lumber, in hybrid cross-laminated timber (HCLT), lead to their dimensional stability and bonding performance more complex than generic cross-laminated timber (CLT). In this paper, the spruce-pine-fir (SPF) dimension lumber and construction oriented strand board (COSB) were employed to fabricate HCLT. The effects of four configurations and three adhesives on the dimensional stability and bonding performance of CLT and HCLT were evaluated in term of the water absorption (WA), thickness swelling (TS), block shear strength (BSS), wood failure percentage (WFP) and rate of delamination (RD). The results showed that with the increase of the COSB laminations, the WA of HCLT specimens decreased, and the values of TS, BBS and WFP increased. The configuration had a significant influence on the dimensional stability, BBS and WFP of the specimen. The adhesive had a significant influence on the dimensional stability and some bonding performances of the specimen. The phenol resorcinol formaldehyde (PRF) specimens had the lowest average RD value compared with the one-component polyurethane (PUR) and emulsion polymer isocyanate (EPI) specimens. Failures were prone to occur in the middle of the thickness of COSB lamination during block shear and delamination tests. The outcome of this paper could help the engineering application of HLCT.
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Modelling of R22+ wood-frame walls. Model validation with experimental measurements

https://research.thinkwood.com/en/permalink/catalogue3199
Year of Publication
2022
Topic
Moisture
Application
Walls
Author
Neal, Holcroft
Organization
FPInnovations
Year of Publication
2022
Format
Report
Application
Walls
Topic
Moisture
Keywords
Wood Frame Wall
Hygrothermal
Insulation
Vapour Control
Research Status
Complete
Summary
The overall objective of this study is to provide information to building design practitioners that will help to improve accuracy of hygrothermal models and enable them to better use these models to predict the durability and thermal performance of wood-based building envelopes. To achieve this, hygrothermal models using WUFI Pro software are validated with experimental data obtained from five wood-frame wall assemblies, with different insulation and vapour control strategies, exposed to the climatic conditions of Vancouver from October 2018 to May 2020. This exercise provides a set of model input parameters that the practitioner can use to assess similar structures exposed to similar environmental conditions. Sensitivity analysis is conducted on the model input parameters to establish which are the most important in obtaining a good fit to experimental measurements, and therefore accurate prediction of assembly performance. There is also discussion on limitations of the hygrothermal model.
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Moisture Monitoring of a CLT Structure in a Southern Climate

https://research.thinkwood.com/en/permalink/catalogue3218
Year of Publication
2022
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Poblete, Elizabeth
Messadi, Tahar
Murray, Cameron
Zelinka, Samuel
Organization
University of Arkansas
Forest Products Laboratory
Publisher
ASCE
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Moisture
Keywords
Wood Moisture Relations
Building Health
Remote Sensing
Research Status
Complete
Series
Journal of Architectural Engineering Journal
Summary
Understanding moisture behavior in cross-laminated timber (CLT) is critical to the widespread use of CLT in construction in the United States. Currently, very little data exist on the long-term impact of moisture on CLT in real structures. The objective of this research was to collect data regarding the long-term moisture variation in the CLT panels at the University of Arkansas student residential building, named Adohi Hall. The climate of Northwest Arkansas is different from those of previously monitored buildings, mostly located in the Pacific Northwest. Comparatively, Northwest Arkansas has a warmer climate with higher average annual precipitation. Moisture sensors were installed in 45 locations throughout the building to provide a comprehensive evaluation of the building. Results indicate that for the interior floors of the building, i.e., not the roof, CLT panels have not encountered moisture intrusions. At the roof level, moisture intrusions during construction were trapped in the CLT panels by waterproofing. This trapped moisture resulted in slower drying to below acceptable levels of moisture.
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Post-layup protection of mass timber elements in above ground protected exposures: 2-year results

https://research.thinkwood.com/en/permalink/catalogue3234
Year of Publication
2022
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Author
Mankowski, Mark E.
Shelton, Thomas
Kirker, Grant T.
Morrell, Jeffrey J.
Organization
Forest Products Laboratory
University of the Sunshine Coast
Year of Publication
2022
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Moisture
Keywords
Mass Panel Plywood
AWPA Standard E21
Above Ground Testing
Soil Termiticide
Borate
Field Test
Durability
Decay
Termite
Conference
Proceedings IRG Annual Meeting (ISSN 2000-8953)
Research Status
Complete
Summary
Mass timber has seen increased use as a building material for low and mid-rise construction in recent decades. The durability of mass timber elements has not been fully examined and the effects of wood destroying organisms on this these materials merits attention. The effectiveness of currently labeled soil termiticides and passively applied biocides at post-construction or as remedial agents needs to be evaluated for mass timber used in structures, particularly in areas with elevated risk of termite attack. The ability of soil insecticidal drenches or spray-on insecticide/fungicide treatments for protecting mass timber in service was assessed with a modified AWPA Standard E21 above-ground test using three ply Douglas-fir or southern pine cross-laminated timber as well as Douglas-fir mass plywood panels. Samples of each material (305 x 102 x 102 mm) were installed in an above ground protected test at the Harrison Experimental Forest (HEF) (Saucier, Mississippi) in September, 2019. Six replicates of five treatments including soil termiticide, no treatment, spray-on borate at initiation, borate rods and remedial treatment, using spray on borate of attacked material after two years, were tested. Samples were left undisturbed for two years and then examined and rated. Near surface moisture content increased to levels approaching the fiber saturation point over the two-year non-disturbance period. Untreated control samples were attacked by both decay fungi and termites. Samples treated with borates at test initiation showed limited decay or termite attack. Soil termiticide treated plots showed no sign of termite attack, but some samples had heavy decay compared to non-soil termiticide treated plots.
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Moisture-Related Risks in Wood-Based Retrofit Solutions in a Mediterranean Climate: Design Recommendations

https://research.thinkwood.com/en/permalink/catalogue3259
Year of Publication
2022
Topic
Moisture
Author
Urso, Alessandra
Costanzo, Vincezo
Nocera, Francesco
Evola, Gianpiero
Organization
University of Catania
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Topic
Moisture
Keywords
Hygrothermal Simulations
Moisture-related Risks
Wood-based Envelope Solutions
Thermal Insulation
Research Status
Complete
Series
Sustainability
Summary
Nowadays, advanced hygrothermal simulation tools are available and they are widely used to predict moisture-related risks in building components, such as mold growth and increased conductive heat losses. This paper takes advantage of these capabilities to analyze moisture-related risks in the innovative wood-based retrofit solutions, developed in the ongoing H2020 “e-SAFE” project. In particular, simulations carried out through the Delphin software for the warm Mediterranean climate of Catania (Italy) allowed assessing the effectiveness of several insulating materials used in the wall assembly and the moisture-related performance determined by adopting either a waterproof membrane or a vapor barrier in convenient positions. The results show that the solutions with highly permeable and highly moisture-capacitive insulation (e.g., wood fiber) are mold free, but at the expense of increased heat losses by up to 12%, compared to dry materials). In some circumstances, foam glass or extruded polyurethane could be preferable, due to their high resistance to mold growth and their flat sorption curve. The vapor-open waterproof membrane applied to the outer side of the insulation is suggested, while a vapor barrier on the outer side of the existing wall worsens mold-related issues.
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146 records – page 1 of 15.