This study aims at assessing the changes happening within the residential construction industry with respect to walls. There are three major goals of this study. The first is to assess the attributes demanded by builders in single family wall products and systems. The second is to assess product usage and substitution in single-family walls. The third aim is to assess the move to component building in residential walls.
A mail out survey was sent to single-family homebuilders in the US, one randomly drawn list of builders plus a list of the top 100 builders in the country. The survey covered builders concerns, attributes demanded in walls, and products and systems used for walls.
Results indicated that energy codes were the top concern of builders. Interestingly, very few builders were concerned with engineered wood or prefabricated systems availability, but lumber availability was considered a constraint by some firms, especially the large ones.
With respect to walls attributes it is clear that the most important attribute of a wall is straightness and square. However, the next three most important attributes are related to on-site issues; speed of assembly, easy to handle, and low on-site waste. This was especially true for large builders. Cost factored in as moderately important with installed cost finishing ahead of material cost.
With respect to walls systems it was found that over 40% of builders have tried prefabricated wood walls. This was strongest in the North. Large builders also were high users of prefabricated wood walls. Prefabricated exterior walls were more common than prefabricated interior walls. Many builders, especially those in the West, used site-built steel for interior walls. In fact, it would appear that of the prefabricated wood interior walls and site-built steel are substitutes.
Labour availability is an equal, if not greater, factor than product availability in the competition among building products and systems for residential construction today. Further, demographic forecasts show labour availability decreasing into the future. At the same time the consolidation of residential building firms is giving rise to more automation and off-site building. For these reasons, it is safe to assume that prefabricated building will only increase into the future. Therefore, it is imperative that the wood products industry defines how the competitive advantage their products have always had in the residential construction industry can be adapted and maintained in an era of prefabricated construction.
A concept for an outdoor test facility in Vancouver for building enclosure materials and components has been under study by Forintek and others since Fall 2000. Phase One - a preliminary feasibility study - was previously completed. This report describes accomplishments to date of Phase Two, a transition phase involving identification of a project custodian, further concept development, development of a business plan, preparation for fundraising and identification of potential sites.
The key objectives of this project are to develop two-way technology transfer instruments that achieve a connection with specifiers, designers, builders, homeowners and maintenance supervisors, and to explore opportunities for collaborative field studies of durability performance where information gaps exist.
The objectives of this project are to develop two-way technology transfer instruments that achieve a connection with specifiers, designers, builders, homeowners and maintenance supervisors and to explore opportunities for collaborative field studies of durability performance where information gaps exist. The web site on durability is proving an outstanding mechanism for technology transfer with 482 unique visitors in February 2002.
The ultimate goal of the project is to increase confidence in the durability of wood construction, and thereby lead to greater use of wood products in China. This report aims to assess wood-durability related climate, termite, and decay loads, to inform those building wood structures. Specifically a decay hazard map for exterior above-ground wood structures was refined and a termite map was updated. Based on the decay and termite hazards, four biological hazard zones were proposed: low hazard zone with low decay hazard and no termites, moderate hazard zone with moderate decay hazard but no termites, moderate hazard zone with moderate decay hazard and Reticulitermes, and severe hazard zone with severe decay hazard and both Reticulitermes and Coptotermes. It is hoped that the information can be used by designers and builders as a general guide for designing for certain climate loads and biological hazards, and such a classification will pave the way for developing appropriate requirements for wood protection against decay and termites in different regions in China. The report also sends a strong message that compared to North America, China has a much larger area with a severe or moderate hazard. Hence proper wood protection is critical for achieving durability of wood construction.
Despite their excellent mechanical properties, Engineered Wood Products (EWP) like Laminated Veneer Lumber (LVL), Parallel Strand Lumber (PSL) and Laminated Strand Lumber (LSL) have not been widely used in structural applications. Such products have largely been employed as substitutes for sawn lumber materials in 'small building' applications. To change this, it is essential that engineers gain knowledge of the strength and stiffness characteristics of mechanical connections, to supplement what is known about properties of EWP themselves.
This project was aimed at developing generalized structural design information for mechanical connections in (EWP), taking into account the physical characteristics of such products.
The wood products industry wants to expand its market share in non-residential buildings. This is a challenging goal because building codes exhibit a bias against the use of wood products, particularly in the construction of non-residential buildings. The move towards adoption of performance-based building codes offers the promise of eliminating such biases. However, in order to be prepared for the introduction of performance-based codes, architects, engineers and building code officials have pointed out the need for engineering tools to assess the fire performance of buildings.
This five-year project was initiated to develop fire-safety design tools for non-residential wood-frame buildings, and to foster development and delivery of educational programs to train students and practitioners in performance-based fire-safety design. In order to achieve these goals an NSERC Industrial Research Chair in Fire Safety Engineering was established at Carleton University in March of 2001. This report summarises the progress towards these goals made by the Chair in his first year of tenure.
This Interim Report of the research project "Improved prediction of seismic resistance of Part 9 Houses" under the CMHC External Research Program presents a detailed literature review of research relevant to lateral resistance of conventional wood-frame construction and an assessment of three mechanics-based methods for calculating lateral capacity.
The relative performance of the three mechanics-based methods is ascertained by comparing the test data of lateral capacities of partially restrained wall specimens having window openings with the predicted results from the calculation methods. Method 1 by Ni and Karacabeyli (2000, 2002) is the simplest to use and gave the most conservative results; Method 2 by Källsner et al., (2001, 2002) is less conservative but more complicated, and Method 3 by Källsner and Gurhammar (2005, 2006) gives non-conservative results.
In the next phase of the project, these mechanics-based methods will be further calibrated against pertinent shake table results from the recent UBC "Earthquake 99" project and from the Forintek – Tongji University tests of conventional wood-frame construction. They will then be employed in the determination of the seismic response of houses as prescribed by the seismic part of the Engineering Guide for Wood Frame Construction published by the Canadian Wood Council.
Support industry to expand its markets for wood and wood products by providing designers and specifiers with design provisions and practical design solutions for wood-based lateral load resisting systems in engineered wood construction. This four-year project will address two main issues:
Develop and compile the fundamental information needed to establish a Lateral Load Resisting Systems Design Section in CSA O86, which will be consistent with the 2005 edition of the National Building Code of Canada (NBCC 2005).
Develop and compile the information needed to link the new Lateral Load Resisting Systems Design Section in CSA O86 with the Fastenings Section in terms of connection behaviour required to satisfy the specified system response to lateral loading.