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Effects of Climate Change on the Moisture Performance of Tallwood Building Envelope

https://research.thinkwood.com/en/permalink/catalogue2771
Year of Publication
2021
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Application
Building Envelope
Walls
Author
Defo, Maurice
Lacasse, Michael
Publisher
MDPI
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Building Envelope
Walls
Topic
Moisture
Keywords
Climate Change
Hygrothermal Simulations
Moisture Performance
Durability
Mold Growth Risk
Language
English
Research Status
Complete
Series
Buildings
Summary
The objective of this study was to assess the potential effects of climate change on the moisture performance and durability of massive timber walls on the basis of results derived from hygrothermal simulations. One-dimensional simulations were run using DELPHIN 5.9.4 for 31 consecutive years of the 15 realizations of the modeled historical (1986–2016) and future (2062–2092) climates of five cities located across Canada. For all cities, water penetration in the wall assembly was assumed to be 1% wind-driven rain, and the air changes per hour in the drainage cavity was assumed to be 10. The mold growth index on the outer layer of the cross-laminated timber panel was used to compare the moisture performance for the historical and future periods. The simulation results showed that the risk of mold growth would increase in all the cities considered. However, the relative change varied from city to city. In the cities of Ottawa, Calgary and Winnipeg, the relative change in the mold growth index was higher than in the cities of Vancouver and St. John’s. For Vancouver and St. John’s, and under the assumptions used for these simulations, the risk was already higher under the historical period. This means that the mass timber walls in these two cities could not withstand a water penetration rate of 1% wind-driven rain, as used in the simulations, with a drainage cavity of 19 mm and an air changes per hour value of 10. Additional wall designs will be explored in respect to the moisture performance, and the results of these studies will be reported in a future publication. View Full-Text
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Field Hygrothermal Performance of R22+ Wood-Frame Walls in Vancouver

https://research.thinkwood.com/en/permalink/catalogue2775
Year of Publication
2021
Topic
Moisture
Energy Performance
Material
Light Frame (Lumber+Panels)
Application
Walls
Author
Wang, Jieying
Organization
FPInnovations
Year of Publication
2021
Country of Publication
Canada
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Walls
Topic
Moisture
Energy Performance
Keywords
Hygrothermal Performance
Exterior Wall
Mid-Rise
Panels
Language
English
Research Status
Complete
Summary
A test program was conducted to generate hygrothermal performance data for light-wood-frame exterior walls meeting the R22 effective (RSI 3.85) requirement for buildings up to six storeys in the City of Vancouver. Six types of exterior wall assemblies, with 12 wall panels in total, were tested using a test hut located in the rear yard of FPInnovations’ Vancouver aboratory. This document provides a brief summary of the test and performance of these walls based on the data collected over the 19 months’ period from October 2018 to May 2020
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Finite-Element-Based Prediction of Moisture-Induced Crack Patterns for Cross Sections of Solid Wood and Glued Laminated Timber Exposed to a Realistic Climate Condition

https://research.thinkwood.com/en/permalink/catalogue2764
Year of Publication
2021
Topic
Moisture
Serviceability
Material
Glulam (Glue-Laminated Timber)
Author
Autengruber, Maximilian
Lukacevic, Markus
Gröstlinger, Christof
Füssl, Josef
Publisher
ScienceDirect
Year of Publication
2021
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Moisture
Serviceability
Keywords
Eurocode 5
Finite Element Simulation
Finite Element Method (FEM)
Failure
Cracks
Load Bearing Capacity
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
Moisture may significantly influence the dimensions and behavior of wooden elements and, thus, it is important to consider within both serviceability as well as ultimate limit state designs. Dimensional changes, also called swelling (during wetting) and shrinkage (during drying), are non-uniform due to the direction-dependent expansion coefficients of wood and usually lead to eigenstresses. If these exceed certain strength values, cracking may occur, which reduces the resistance to external loads, especially to shear stresses. The current standard Eurocode 5 takes these circumstances very simplified into account, by so-called service classes, defined based on the surrounding climate and average moisture levels over the course of a year. Accordingly, reduction factors for strength values and cross section widths are assigned. For a better understanding of the climate-induced changes in wooden beams, we exposed 18 different beams with varying cross sections to a representative climate of Linz, Austria, within the framework of a finite element simulation and investigated the resulting moisture fields and crack patterns. For this purpose, expansions and linear-elastic stresses were simulated by using the thermal and moisture fields obtained in the first simulation step and expansion coefficients. Using a multisurface failure criterion, two critical points in time were determined for each cross section, at which advanced crack simulations were carried out using the extended finite element method. The resulting crack lengths showed that the Eurocode 5 assumption of a linear relationship between crack-free and total width could be verified for both drying and wetting cases. In future, the obtained crack patterns might also be used to investigate the actual reduction of load-bearing capacities of such cross sections, since the position of a crack and, for example, the maximum shear stress may not coincide. For the first time in this work, a consistent concept is presented to estimate the resulting crack formation in a wooden element from any moisture load based on a mechanical well-founded simulation concept. For this reason, this work is intended to lay a basis for a more accurate consideration of climate-related loads on wooden elements up to timber constructions.
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Mass Timber Building Science Primer

https://research.thinkwood.com/en/permalink/catalogue2797
Year of Publication
2021
Topic
Design and Systems
Moisture
Fire
Acoustics and Vibration
General Information
Connections
Market and Adoption
Serviceability
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
NLT (Nail-Laminated Timber)
Application
Wood Building Systems
Author
Kesik, Ted
Martin, Rosemary
Organization
Mass Timber Institute
RDH Building Science
Publisher
Mass Timber Institute
Year of Publication
2021
Country of Publication
Canada
Format
Book/Guide
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
NLT (Nail-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Moisture
Fire
Acoustics and Vibration
General Information
Connections
Market and Adoption
Serviceability
Keywords
Mass Timber
Building Science
Language
English
Research Status
Complete
Summary
The development of this primer commenced shortly after the 2018 launch of the Mass Timber Institute (MTI) centered at the University of Toronto. Funding for this publication was generously provided by the Ontario Ministry of Natural Resources and Forestry. Although numerous jurisdictions have established design guides for tall mass timber buildings, architects and engineers often do not have access to the specialized building science knowledge required to deliver well performing mass timber buildings. MTI worked collaboratively with industry, design professionals, academia, researchers and code experts to develop the scope and content of this mass timber building science primer. Although provincially funded, the broader Canadian context underlying this publication was viewed as the most appropriate means of advancing Ontario’s nascent mass timber building industry. This publication also extends beyond Canada and is based on universally applicable principles of building science and how these principles may be used anywhere in all aspects of mass timber building technology. Specifically, these guidelines were developed to guide stakeholders in selecting and implementing appropriate building science practices and protocols to ensure the acceptable life cycle performance of mass timber buildings. It is essential that each representative stakeholder, developer/owner, architect/engineer, supplier, constructor, wood erector, building official, insurer, and facility manager, understand these principles and how to apply them during the design, procurement, construction and in-service phases before embarking on a mass timber building project. When mass timber building technology has enjoyed the same degree of penetration as steel and concrete, this primer will be long outdated and its constituent concepts will have been baked into the training and education of design professionals and all those who fabricate, construct, maintain and manage mass timber buildings. One of the most important reasons this publication was developed was to identify gaps in building science knowledge related to mass timber buildings and hopefully to address these gaps with appropriate research, development and demonstration programs. The mass timber building industry in Canada is still a collection of seedlings that continue to grow and as such they deserve the stewardship of the best available building science knowledge to sustain them until such time as they become a forest that can fend for itself.
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Free
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Mass Timber Design Manual

https://research.thinkwood.com/en/permalink/catalogue2780
Year of Publication
2021
Topic
Acoustics and Vibration
Connections
Cost
Design and Systems
Energy Performance
Environmental Impact
Fire
General Information
Moisture
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
NLT (Nail-Laminated Timber)
Application
Wood Building Systems
Organization
WoodWorks
Think Wood
Year of Publication
2021
Country of Publication
United States
Format
Book/Guide
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
NLT (Nail-Laminated Timber)
Application
Wood Building Systems
Topic
Acoustics and Vibration
Connections
Cost
Design and Systems
Energy Performance
Environmental Impact
Fire
General Information
Moisture
Keywords
Mass Timber
United States
Building Systems
Tall Wood
Sustainability
IBC
Applications
Language
English
Research Status
Complete
Summary
This manual is helpful for experts and novices alike. Whether you’re new to mass timber or an early adopter you’ll benefit from its comprehensive summary of the most up to date resources on topics from mass timber products and applications to tall wood construction and sustainability. The manual’s content includes WoodWorks technical papers, Think Wood continuing education articles, case studies, expert Q&As, technical guides and other helpful tools. Click through to view each individual resource or download the master resource folder for all files in one handy location. For your convenience, this book will be updated annually as mass timber product development and the market are quickly evolving.
Online Access
Free
Resource Link
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Mass Timber Envelopes in Passivhaus Buildings: Designing for Moisture Safety in Hot and Humid Australian Climates

https://research.thinkwood.com/en/permalink/catalogue2840
Year of Publication
2021
Topic
Moisture
Energy Performance
Material
CLT (Cross-Laminated Timber)
Application
Building Envelope
Author
Strang, Marcus
Leardini, Paola
Brambilla, Arianna
Gasparri, Eugenia
Organization
University of Queensland
University of Sydney
Editor
Medved, Sergej
Publisher
MDPI
Year of Publication
2021
Country of Publication
Australia
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Building Envelope
Topic
Moisture
Energy Performance
Keywords
Hygrothermal
Moisture Safety
Durability
Passive House
Envelope
Language
English
Research Status
Complete
Series
Buildings
Summary
The uptake of buildings employing cross-laminated timber (CLT) assemblies and designed to Passivhaus standard has accelerated internationally over the past two decades due to several factors including responses to the climate crisis by decarbonising the building stock. Structural CLT technology and the Passivhaus certification both show measurable benefits in reducing energy consumption, while contributing to durability and indoor comfort. However, there is a general lack of evidence to support a fast uptake of these technologies in Australia. This paper responds to the compelling need of providing quantitative data and adoption strategies; it explores their combined application as a potential pathway for climate-appropriate design of energy-efficient and durable mass timber envelope solutions for subtropical and tropical Australian climates. Hygrothermal risk assessments of interstitial condensation and mould growth of CLT wall assemblies inform best-practice design of mass timber buildings in hot and humid climates. This research found that the durability of mass timber buildings located in hot and humid climates may benefit from implementing the Passivhaus standard to manage interior conditions. The findings also suggested that climate-specific design of the wall assembly is critical for mass timber buildings, in conjunction with excellent stormwater management practices during construction and corrosion protection for metallic fasteners.
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Free
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Le Rendement Hygrothermique de Murs à Ossature de Bois R22+ à Vancouver

https://research.thinkwood.com/en/permalink/catalogue2776
Year of Publication
2021
Topic
Moisture
Energy Performance
Material
Light Frame (Lumber+Panels)
Application
Walls
Author
Wang, Jieying
Organization
FPInnovations
Year of Publication
2021
Country of Publication
Canada
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Walls
Topic
Moisture
Energy Performance
Keywords
Hygrothermal Performance
Exterior Wall
Mid-Rise
Panels
Language
French
Research Status
Complete
Summary
Un programme d’essais a été réalisé en vue de générer des données sur le rendement hygrothermique des murs à ossature légère de bois qui répondent à l’exigence R22 (RSI 3,85) pour les bâtiments d'au plus six étages à Vancouver. Six types d’assemblage de mur extérieur, avec un total de 12 murs extérieurs, ont été mis à l’essai à l’aide d’une hutte d’essai située dans la cour arrière du laboratoire de FPInnovations à Vancouver. Le présent document présente un court résumé de l’essai et du rendement de ces murs en se basant sur les données recueillies sur une période de 19 mois, soit d’octobre 2018 à mai 2020 (Wang 2021).
Online Access
Free
Resource Link
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Testing R22+ Wood-Frame Walls for Hygrothermal Performance in the Vancouver Climate: Field Wall Performance

https://research.thinkwood.com/en/permalink/catalogue2768
Year of Publication
2021
Topic
Energy Performance
Moisture
Material
Light Frame (Lumber+Panels)
Application
Walls
Author
Wang, Jieying
Organization
FPInnovations
Year of Publication
2021
Country of Publication
Canada
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Walls
Topic
Energy Performance
Moisture
Keywords
Mid-Rise
Energy Efficiency
Exterior Wall
Hygrothermal
Multi-Storey
Language
English
Research Status
Complete
Summary
This new study aims to generate hygrothermal, particularly moisture-related performance data for light wood-frame walls meeting the R22 effective (RSI 3.85) requirement for buildings up to six storeys in the City of Vancouver. The overarching goal is to identify and develop durable exterior wood-frame walls to assist in the design and construction of energy efficient buildings across the country. Twelve test wall panels in six types of wall assemblies are assessed in this study. The wall panels, each measuring 4 ft. (1200 mm) wide and 8 ft. (2400 mm) tall, form portions of the exterior walls of a test hut located in the rear yard of FPInnovations’ Vancouver laboratory. This report, second in a series on this study, documents the performance of these wall assemblies based on the data collected over 19 months’ period from October 2018 to May 2020, covering two winter seasons and one summer.
Online Access
Free
Resource Link
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Variations of Moisture Content in Manufacturing CLT-Concrete Composite Slab Using Wet Construction Method

https://research.thinkwood.com/en/permalink/catalogue2732
Year of Publication
2021
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Author
Song, Yo-Jin
Baek, Seong-Yeob
Lee, In-Hwan
Hong, Soon-Il
Publisher
North Carolina State University
Year of Publication
2021
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Topic
Moisture
Keywords
Wet Construction Method
Moisture Content
Teak
Composite
Adhesive
Delamination
Language
English
Research Status
Complete
Series
BioResources
Summary
Construction of eco-friendly high-rise buildings using cross-laminated timber (CLT)-concrete composite (CCC) slabs is increasing. CLT and concrete, which are major component materials of the CCC slab, are significantly affected by moisture. In particular, the moisture content of concrete in the production process affects the quality of both materials. In this study, the effects of the wet construction method on CLT and concrete component materials are examined by monitoring the behavior of the CCC slab during curing time (28 d) and by evaluating the quality of the concrete and CLT after curing. When manufacturing the CCC using the wet construction method, moisture penetration from the concrete into the CLT during the curing time is suppressed by the shear bonding between the concrete and the CLT when an adhesive is used. This minimizes the effect of the moisture on both component materials, consequently yielding uniform compressive strength to the concrete after curing and preventing the deterioration of the CLT’s delamination performance. Therefore, the shear bonding method using an adhesive is expected to minimize the quality deterioration observed in concrete and CLT after curing.
Online Access
Free
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Construction Moisture Management, Cross Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2685
Year of Publication
2020
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Author
Wang, Jieying
Organization
FPInnovations
Year of Publication
2020
Country of Publication
Canada
Format
Book/Guide
Material
CLT (Cross-Laminated Timber)
Topic
Moisture
Keywords
Wetting
Risk Mitigation
Drying
Language
English
Research Status
Complete
Summary
Cross-Laminated Timber (CLT) is an engineered mass timber product manufactured by laminating dimension lumber in layers with alternating orientation using structural adhesives. It is intended for use under dry service conditions and is commonly used to build floors, roofs, and walls. Because prolonged wetting of wood may cause staining, mould, excessive dimensional change (sometimes enough to fail connectors), and even result in decay and loss of strength, construction moisture is an important consideration when building with CLT. This document aims to provide technical information to help architects, engineers, and builders assess the potential for wetting of CLT during building construction and identify appropriate actions to mitigate the risk.
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Free
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123 records – page 1 of 13.