Wood use in nonresidential buildings: opportunities and barriers.

Abstract

The North American nonresidential construction sector represents a substantial market for structural building materials, yet it is relatively untapped by wood. This study explored wood use and perceptions held by architects and engineers with respect to the structural use of wood in nonresidential buildings, using an extensive mail survey and a series of specifier focus groups in select geographic regions. Several clear barriers for wood emerged across code, technology transfer, and research and development categories. Key problem areas identified were fire-related building code limitations, wood's cost-competitiveness with steel, wood's design difficulty, and poor training for designers and wood tradespeople. Recommendations for addressing these impediments in both the short and long term are offered.

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An examination of wood's potential as a nonresidential structural material in North America was performed from June 2000 to April 2001. (1) The purpose of this study was to 1) gather information on current wood usage; 2) determine what types of buildings are currently popular in this market; 3) assess the attitudes and knowledge levels of designers regarding wood; 4) understand the people and factors that influence structural material selection; 5) identify barriers to wood in this market; and 6) search for opportunities for wood in this market.

At $292.3 billion in 2000, the total value of new nonresidential construction in the United States was 110 percent that of new residential construction (USBC 2002), representing a substantial market for all construction materials. Yet, according to a recent study on nonresidential wood product usage, only 1.5 billion board feet of lumber and 1.2 billion ft.[.sup.2] of structural panels were used in that sector in 1995 (McKeever and Adair 1998). This is approximately equivalent to only 10 percent of the total wood usage in the new residential construction sector and has been in decline since 1985 (WPC 1987).

Nonresidential buildings are all those not meant for habitation: offices, schools, hospitals, warehouses, etc. Of course, wood is not always an appropriate choice for these types of buildings; indeed, building codes restrict the structural use of wood within this market to smaller buildings. However, code-related issues are only estimated to limit wood's potential nonresidential market share to approximately 50 percent (Goetzl and McKeever 1999). Given the small share held by wood to date, this represents tremendous room for growth.

There have been relatively few studies recently that assess the market potential for wood products in nonresidential construction. Two notable examples are the works of McKeever and Adair (1998) and Kozak and Cohen (1999). McKeever and Adair (1998) found that the potential for increased wood use in this sector is substantial, including the use of wood in combination with steel and concrete construction types. They concluded that the use of wood in nonresidential construction is a function of building size and type, among other factors. For example, there are possibilities to increase wood use in smaller nonresidential structures like stores, office buildings, and schools. Kozak and Cohen (1999) used survey methodologies to not only assess the market potential for wood products in the nonresidential sector, but also to address issues pertaining to why wood was or was not being used in this context. According to their results, there exist many possibilities for producers of wood products to make market inroads into this sector, especially in "wood-friendly" regions of North America. However, marketing efforts must be targeted with varying promotional messages in low-, moderate-, and high-use wood segments.

The present work further studies why wood is not a preferred structural material in the nonresidential construction market and explores means for increasing its use in this context. The results of previous work (Spelter and Anderson 1985, McKeever and Adair 1998, Kozak and Cohen 1999) required updating and were not strongly conclusive regarding the selection process and the hurdles for wood. This is largely due to the difficulty of performing scientifically valid research on the decision-making process of designers. It is difficult to pinpoint the material selection decision to a single point in time, not to mention to clearly identify all the decision makers and their reasons (Mackinder 1980). In addition, decision making in design can be described as a non-linear and non-optimized process. This lack of a systematic approach to the design of buildings makes study of the process a substantial challenge.

Methods

The methodologies used in this study employed various survey techniques in three phases. Data was collected by means of 1) a pre-survey focus group; 2) a mail survey of structural engineers and architects; and 3) a series of post-survey focus groups.

Each is discussed in turn. It should be noted that the decision to use a multipronged approach is based largely on lessons learned from similar studies undertaken previously (e.g., Kozak and Cohen 1999). Researchers felt that many of the issues relating to wood use and specification were too complicated and difficult to capture using traditional quantitative techniques alone. Thus, quantitative and qualitative methods were used in concert in order to address some of these issues.

First, exploratory research was conducted as a means of gathering preliminary information and guidance for the development of the survey instrument. In particular, researchers wished to better understand the many complexities and nuances of the material specification process prior to crafting and implementing a mail questionnaire. A focus group session with five architects, four structural engineers, and one code consultant was held in Vancouver in June 2000. The focus group participants were also asked to act as survey pre-testers prior to the questionnaire being mailed out.

Upon completion of the exploratory focus group session, mail surveys were designed and sent to 6,000 architects and structural engineers throughout the United States and Canada in the fall of 2000. The survey instrument was based on previous work by Kozak and Cohen (1999) and adhered largely to methods prescribed by the Tailored Design Method (Dillman 2000). The choice to use self-administered mail questionnaires served the need to reach a geographically dispersed audience in a cost-effective manner.

The survey itself was 12 pages in length, consisting of 7 sections: 1) building design; 2) structural material use; 3) wood use in nonresidential buildings; 4) learning about building materials and design; 5) design processes and philosophy; 6) environmental issues; and 7) …