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Decision aids for durable wood construction : review and redirection

https://library.fpinnovations.ca/en/permalink/fpipub41201
Author
O'Connor, J.
Morris, Paul I.
Date
March 1999
Material Type
Research report
Field
Sustainable Construction
of the assembly such as building paper and flashing, to enforce the building code requirement that the moisture
Author
O'Connor, J.
Morris, Paul I.
Contributor
Canada. Canadian Forest Service.
Date
March 1999
Material Type
Research report
Physical Description
28 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Building construction
Planning
Design
Moisture content
Series Number
Canadian Forest Service No. 19
Project No. 1052
W-1611
Location
Vancouver, British Columbia
Language
English
Abstract
The project Decision Aids for Durable Wood Construction underwent a major review with the hiring of a new project leader (O'Connor) in September 1998. In consultation with the project liaisons, the work on this project since its start-up in 1993 was examined, the primary task of developing a computer-based tool for the building industry was reconsidered, the context of worldwide research into building envelope moisture failures was reviewed, and a revised project plan was proposed. Decision Aids was a self-contained project for its first three years, with efforts concentrated on knowledge acquisition, expert system experimentation and other foundation work for development of a computer tool. With a rise of interest in building envelope moisture failures across North America and elsewhere, Decision Aids activity shifted into a mode that was reactive to projects and events external to Forintek. This was necessary due to the level of effort external agencies, media and research labs were devoting to the topic. In particular, where the actions of outsiders began to have an influence on wood in construction, we found it critical to participate in order to ensure the fair and correct treatment of wood. The new project leader was asked to review the project and either get the project back on its original track or suggest a redirection. The project goal, to assist end users in best application of wood, was determined to be sound. In addition, the project leader recommended that resources continue to be allocated to participation in outside research efforts and other related activities. However, it was recommended that the project objective to develop computer-based decision tools be reassessed. Instead, the project leader recommended a course of action focused on tasks both shorter in term and smaller in scope, which will enable Forintek to deliver results better tailored to the immediate needs of industry in a time of building envelope moisture failure "crisis." The new project plan is split into two areas: 1) address building envelope moisture failures that are due to existing information not arriving in the right hands (i.e., a technology transfer problem); and 2) address building envelope moisture failures that are due to a lack of information (i.e., a research problem). The technology transfer area will create a formal plan for communication to the building industry, will enable Forintek to experiment with developing pathways to that new target audience, and will provide the means for the wood industry to provide helpful durability information to the public through a relatively neutral third party (Forintek). The research area will explore opportunities for limited scope experiments or collaborative field studies of wood system durability performance, with the intent of verifying or modifying codes, standards and best practice guides.
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L'eau et la durabilité : fiche technique sur la performance de la construction à ossature de bois

https://library.fpinnovations.ca/en/permalink/fpipub42416
Contributor
Forintek Canada Corp.
Canada Mortgage and Housing Corporation (CMHC)
Société centrale d'hypothèques et de logement (SCHL)
Date
April 2000
Material Type
Pamphlet
Field
Sustainable Construction
Contributor
Forintek Canada Corp.
Canada Mortgage and Housing Corporation (CMHC)
Société centrale d'hypothèques et de logement (SCHL)
Date
April 2000
Material Type
Pamphlet
Physical Description
4 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Moisture content
Wood decay
Series Number
Fact Sheet on Wood in Construction = Fiche technique sur le bois dans la construction
Location
Québec, Québec
Language
French
Abstract
Moisture - Control
Moisture - Prevention
Buildings - Houses - Moisture content
Decay - Prevention
Building construction - Design
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Vertical movement in wood platform frame structures : basics

https://library.fpinnovations.ca/en/permalink/fpipub6026
Author
Doudak, Ghasan
Lepper, P.
Ni, Chun
Wang, Jasmine
Date
October 2013
Edition
42995
Material Type
Research report
Field
Sustainable Construction
D P L A T F O R M F R A M E S T R U C T U R E S: B a si c s Wood moisture content
Author
Doudak, Ghasan
Lepper, P.
Ni, Chun
Wang, Jasmine
Contributor
Canadian Wood Council
Date
October 2013
Edition
42995
Material Type
Research report
Physical Description
10 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Building Systems
Subject
Building construction
Residential construction
Design
Moisture content
Series Number
W-3076
Language
English
Abstract
Movement in structures due to environmental condition changes and loads must be considered in design. Temperature changes will cause movement in concrete, steel and masonry structures. For wood materials, movement is primarily related to shrinkage or swelling caused by moisture loss or gain when the moisture content is below 28% (wood fiber saturation point). Other movement in wood structures may also include: settlement (bedding-in movement) due to closing of gaps between members and deformation due to compression loads, including instantaneous elastic deformation and creep. Differential movement can occur where wood frame is connected to rigid components such as masonry cladding, concrete elevator shafts, mechanical services and plumbing, and where mixed wood products such as lumber, timbers, and engineered wood products are used. Evidence from long-term wood frame construction practices shows that for typical light frame construction up to three storeys high, differential movement can be relatively easily accommodated such as through specifying “S-Dry” lumber. However, differential movement over the height of wood-frame buildings becomes a very important consideration for taller buildings due to its cumulative effect. The APEGBC Technical and Practice Bulletin provides general design guidance and recommends the use of engineered wood products and dimension lumber with 12% moisture content for floor joists to reduce and accommodate differential movement in 5 and 6-storey wood frame buildings. Examples of differential movement concerns and solutions in wood-frame buildings can also be found in the Best Practice Guide published by the Canadian Mortgage and Housing Corporation and the Building Enclosure Design Guide –Wood Frame Multi-Unit Residential Buildings published by the Homeowner Protection Office of BC Housing. This document illustrates the causes and other basic information related to vertical movement in wood platform frame buildings and recommendations on material handling and construction sequencing to protect wood from rain and reduce the vertical movement.
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Vertical movement in wood platform frame structures : design and detailing solutions

https://library.fpinnovations.ca/en/permalink/fpipub6025
Author
Doudak, Ghasan
Lepper, P.
Ni, Chun
Wang, Jasmine
Date
October 2013
Edition
42994
Material Type
Research report
Field
Sustainable Construction
Author
Doudak, Ghasan
Lepper, P.
Ni, Chun
Wang, Jasmine
Contributor
Canadian Wood Council
Date
October 2013
Edition
42994
Material Type
Research report
Physical Description
13 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Building Systems
Subject
Building construction
Residential construction
Design
Moisture content
Series Number
W-3075
Language
English
Abstract
Most buildings are designed to accommodate a certain range of movement. In design, it is important for designers to identify locations where potential differential movement could affect structural integrity and serviceability, predict the amount of differential movement and develop proper detailing to accommodate it. To allow non-structural materials to be appropriately constructed, an estimate of anticipated differential movement should be provided in the design drawings. Simply specifying wood materials with lower MC at time of delivery does not guarantee that the wood will not get wet on construction sites and will deliver lower shrinkage amounts as anticipated. It is therefore important to ensure that wood does not experience unexpected wetting during storage, transportation and construction. Good construction sequencing also plays an important role in reducing wetting, the consequent wood shrinkage and other moisture-related issues. Existing documents such as the APEGBC Technical and Practice Bulletin on 5- and 6-Storey Wood Frame Residential Building Projects, the Best Practice Guide published by the Canadian Mortgage and Housing Corporation (CMHC), the Building Enclosure Design Guide –Wood Frame Multi-Unit Residential Buildings published by the BC Housing- Homeowner Protection Office (HPO) provide general design guidance on how to reduce and accommodate differential movement in platform frame construction.
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Vertical movement in wood platform frame structures : movement prediction

https://library.fpinnovations.ca/en/permalink/fpipub6027
Author
Doudak, Ghasan
Lepper, P.
Ni, Chun
Wang, Jasmine
Date
October 2013
Edition
42996
Material Type
Research report
Field
Sustainable Construction
Author
Doudak, Ghasan
Lepper, P.
Ni, Chun
Wang, Jasmine
Contributor
Canadian Wood Council
Date
October 2013
Edition
42996
Material Type
Research report
Physical Description
9 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Building Systems
Subject
Building construction
Residential construction
Design
Moisture content
Series Number
W-3077
Language
English
Abstract
It is not possible or practical to precisely predict the vertical movement of wood structures due to the many factors involved in construction. It is, however, possible to obtain a good estimate of the vertical movement to avoid structural, serviceability, and building envelope problems over the life of the structure. Typically “S-Dry” and “S-Grn” lumber will continue to lose moisture during storage, transportation and construction as the wood is kept away from liquid water sources and adapts to different atmospheric conditions. For the purpose of shrinkage prediction, it is usually customary to assume an initial moisture content (MC) of 28% for “S-Green” lumber and 19% for “S-Dry” lumber. “KD” lumber is assumed to have an initial MC of 15% in this series of fact sheets. Different from solid sawn wood products, Engineered Wood Products (EWP) are usually manufactured with MC levels close to or even lower than the equilibrium moisture content (EMC) in service. Plywood, Oriented Strand Board (OSB), Laminated Veneer Lumber (LVL), Laminated Strand Lumber (LSL), and Parallel Strand Lumber (PSL) are usually manufactured at MC levels ranging from 6% to 12%. Engineered wood I-joists are made using kiln dried lumber (usually with moisture content below 15%) or structural composite lumber (such as LVL) flanges and plywood or OSB webs, therefore they are usually drier and have lower shrinkage than typical “S-Dry” lumber floor joists. Glued-laminated timbers (Glulam) are manufactured at MC levels from 11% to 15%, so are the recently-developed Cross-laminated Timbers (CLT). For all these products, low shrinkage can be achieved and sometimes small amounts of swelling can be expected in service if their MC at manufacturing is lower than the service EMC. In order to fully benefit from using these dried products including “S-Dry” lumber and EWP products, care must be taken to prevent them from wetting such as by rain during shipment, storage and construction. EWPs may also have lower shrinkage coefficients than solid wood due to the adhesives used during manufacturing and the more mixed grain orientations in the products, including the use of cross-lamination of veneers (plywood) or lumber (CLT). The APEGBC Technical and Practice Bulletin emphasizes the use of EWP and dimension lumber with 12% moisture content for the critical horizontal members to reduce differential movement in 5 and 6-storey wood frame buildings.
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