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Preliminary Assessment of Hygrothermal Performance of Cross-Laminated Timber Wall Assemblies Using Hygrothermal Models

https://research.thinkwood.com/en/permalink/catalogue2628
Year of Publication
2010
Topic
Moisture
Design and Systems
Serviceability
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Walls
Author
Wang, J.
Baldracchi, P.
Organization
FPInnovations
Year of Publication
2010
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Walls
Topic
Moisture
Design and Systems
Serviceability
Keywords
Hygrothermal
Moisture Performance
Rainscreen
Language
English
Research Status
Complete
Summary
Preliminary simulation was carried out using hygIRC and WUFI, both 1-D hygrothermal models, to analyze moisture performance of rainscreened wood-frame walls and cross-laminated timber (CLT) walls for the climates in Vancouver and Calgary. The major results are as follows. In order to provide baseline knowledge, preliminary comparisons between hygIRC and WUFI were conducted to investigate the effects of climate data, wall orientations and rain intrusion on the performance of the rainscreened wood-frame walls based on Vancouver’s climate. hygIRC tended to produce almost constant moisture content (MC) of the plywood sheathing throughout a year but WUFI showed greater variations, particularly when the ventilation of the rainscreen cavity was neglected. Rainscreen cavity ventilation provided dramatic drying potentials for wall assemblies based on the WUFI simulation. hygIRC indicated that east-facing walls had the highest moisture load, but the differences between orientations seemed negligible in WUFI when the rainscreen cavity ventilation was taken into account. When 1% of wind-driven rain was simulated as an additional moisture load, hygIRC suggested that the rainscreen walls could not dry out in Vancouver, WUFI, however, indicated that they could dry to a safe MC level in the summer. The discrepancies in material property data between the two models and between different databases in WUFI (even for the same wood species) were found to be very large. In terms of wood sorption data, large differences existed at near-saturated RH levels. This is a result of using pressure-plate/membrane methods for measuring material equilibrium moisture content (EMC) under high RH conditions. The EMC of wood at near-100% RH conditions measured with these methods can be higher than 200%, suggesting wood in construction would decay without liquid water intrusion or severe vapour condensation. The pressure-plate/membrane methods also appeared to be highly species-dependent, and have higher EMC at a certain RH level for less permeable species, from which it is relatively difficult to remove water during the measurement. The hygrothermal simulation in this work suggested that such a species bias caused by testing methods could put impermeable species (most Canadian species) at a disadvantage to permeable species like southern pine during related durability design of building assemblies. In terms of using CLT for construction in Vancouver and Calgary, the WUFI simulations suggested that the use of less permeable materials such as EPS (expanded polystyrene insulation), XPS (extruded polystyrene insulation), self-adhered bituminous membrane and polyethylene in wall assemblies reduced the ability of the walls to dry. On the other hand, permeable assemblies such as those using relatively permeable insulation like semi-rigid mineral wool (rock wool) as exterior insulation, instead of less permeable exterior insulation materials, would help walls dry. The simulation also suggested that using CLT products with initially low MC would significantly reduce moisture-related risks, which indicated the importance of protecting CLT and avoiding wetting during transportation and construction. In addition, the simulation found that indoor relative humidity (RH) conditions generated by the indoor RH prediction models included in hygIRC and WUFI varied greatly under the same basic climate and building conditions. The intermediate method specified in ASHRAE Standard 160 P resulted in long periods of saturated RH conditions throughout a year for the Vancouver climate, which may not be representative of ordinary residential buildings in Vancouver. The simulation in this study is preliminary and exploratory. It would be arbitrary to recommend one model over the other based on this report or use the simulation results directly for CLT wall assembly design without consultation with building science specialists. However, this work revealed more opportunities for close collaborations between the wood science and the building science communities. More work should be carried out to develop appropriate testing methods and assemble material property data for hygrothermal simulation of wood-based building assemblies. Model improvement and field verification are also strongly recommended, particularly for new building systems such as CLT constructions.
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Free
Resource Link
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Characteristics of the Radio-Frequency/Vacuum Drying of Heavy Timbers for Post and Beam of Korean Style Housings Part II: For Korean Red Pine Heavy Timbers with 250 × 250 mm, 300 × 300 mm in Cross Section and 300 mm in Diameter, and 3,600 mm in Length

https://research.thinkwood.com/en/permalink/catalogue1508
Year of Publication
2011
Topic
Moisture
Material
Solid-sawn Heavy Timber
Application
Wood Building Systems
Author
Lee, Nam-Ho
Zhao, Xue-Feng
Shin, Ik-Hyun
Park, Moon-Jae
Park, Jung-Hwan
Park, Joo-Saeng
Publisher
The Korean Society of Wood Science Technology
Year of Publication
2011
Country of Publication
Korea
Format
Journal Article
Material
Solid-sawn Heavy Timber
Application
Wood Building Systems
Topic
Moisture
Keywords
Radio-Frequency/Vacuum Drying
Moisture Gradient
Shrinkage
Case Hardening
Surface Checks
Compressive Load
Language
Korean
Research Status
Complete
Series
Journal of the Korean Wood Science and Technology
Online Access
Free
Resource Link
Less detail

Hygrothermal Properties of Cross Laminated Timber and Moisture Response of Wood at High Relative Humidity

https://research.thinkwood.com/en/permalink/catalogue12
Year of Publication
2012
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Application
General Application

Moisture Response of Wall Assemblies of Cross-Laminated Timber Construction in Cold Canadian Climates

https://research.thinkwood.com/en/permalink/catalogue143
Year of Publication
2012
Topic
Serviceability
Moisture
Material
CLT (Cross-Laminated Timber)
Application
Walls

Finite Element Modelling of Moisture Related and Visco-Elastic Deformations in Inhomogeneous Timber Beams

https://research.thinkwood.com/en/permalink/catalogue425
Year of Publication
2013
Topic
Mechanical Properties
Moisture
Material
Glulam (Glue-Laminated Timber)
Application
Beams

Cross-Laminated Timber Roof Panels at the Promega Corporation Facility: Documenting Installation and Monitoring In-Service Moisture Conditions

https://research.thinkwood.com/en/permalink/catalogue801
Year of Publication
2013
Topic
Serviceability
Moisture
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Glass, Samuel
Romanin, Jennifer
Schumacher, Jim
Spickler, Kris
Organization
Forest Products Laboratory
Year of Publication
2013
Country of Publication
United States
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Serviceability
Moisture
Keywords
Moisture
Temperature
Installation Process
Sensors
Language
English
Research Status
Complete
Summary
The USDA Forest Products Laboratory (FPL) has, for the past two years, been assisting in removing technical barriers to the use of CLT and trying to develop interest in the United States for its utilization. Coincidentally, Promega Corporation, a leader ...
Online Access
Free
Resource Link
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US Edition - Chapter 10: Building Enclosure Design for Cross-Laminated Timber Construction

https://research.thinkwood.com/en/permalink/catalogue829
Year of Publication
2013
Topic
Design and Systems
Moisture
Material
CLT (Cross-Laminated Timber)
Application
Roofs
Walls
Author
Glass, Samuel
Wang, Jieying
Easley, Steve
Finch, Graham
Organization
FPInnovations
Binational Softwood Lumber Council
Year of Publication
2013
Country of Publication
Canada
United States
Format
Book Section
Material
CLT (Cross-Laminated Timber)
Application
Roofs
Walls
Topic
Design and Systems
Moisture
Keywords
Airflow
Climate
Heat
Moisture Control
Building Enclosure
Exterior Walls
Language
English
Research Status
Complete
Series
CLT Handbook - US Edition
Summary
Cross-laminated timber (CLT) was developed in Europe for the prefabricated construction of wall, roof, and flooring elements. Adaption of CLT for use in the United States requires consideration of the different climates, building codes, and construction methods in this country. ... This Chapter provides guidance on hear, air, and moisture control in wall and roof assemblies that utilize CLT panels in U.S. climate zones. The overarching strategies are to prevent wetting of CLT panels by using drained wall systems, to control airflow using an air barrier on the exterior of the CLT panels, to place rigid insulation to the exterior of the panels, to prevent moisture from accumulating within the panels, and to allow the panels to dry should they get wet. In certain climates, preservative treatment of CLT is recommended to provide additional protection against potential hazards such as decay and termites. ...
Online Access
Free
Resource Link
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Field Study of Hygrothermal Performance of Cross-Laminated Timber Wall Assemblies with Built-In Moisture

https://research.thinkwood.com/en/permalink/catalogue1588
Year of Publication
2013
Topic
Moisture
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
McClung, Victoria
Organization
Ryerson University
Year of Publication
2013
Country of Publication
Canada
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Moisture
Serviceability
Keywords
Hygrothermal
Drying
Wetting
North America
Language
English
Research Status
Complete
Online Access
Free
Resource Link
Less detail

Long Term Monitoring of Timber Bridges - Assessment and Results

https://research.thinkwood.com/en/permalink/catalogue2124
Year of Publication
2013
Topic
Moisture
Serviceability
Material
Timber (unspecified)
Application
Bridges and Spans
Author
Franke, Bettina
Franke, Steffen
Müller, Andreas
Vogel, Mareike
Scharmacher, Florian
Tannert, Thomas
Publisher
Trans Tech Publications
Year of Publication
2013
Country of Publication
Switzerland
Format
Journal Article
Material
Timber (unspecified)
Application
Bridges and Spans
Topic
Moisture
Serviceability
Keywords
Monitoring
Bridge
Moisture Content
Climate
Language
English
Research Status
Complete
Series
Advanced Materials Research
Online Access
Free
Resource Link
Less detail

Numerical Modelling of the Hygro-Thermal Response of Timber Bridges During their Service Life: A Monitoring Case-Study

https://research.thinkwood.com/en/permalink/catalogue2167
Year of Publication
2013
Topic
Serviceability
Moisture
Material
Timber (unspecified)
Application
Bridges and Spans

10 records – page 1 of 1.