C I N T R A F O R
Working Paper 93
Material Substitution Trends
in Residential Construction
1995, 1998 and 2001
Jane Edelson
April 2004
Understanding the ways in which residential builders
perceive and use softwood lumber and substitute structural materials is
essential to the success of any forest products manufacturer. CINTRAFOR completed its first study of
material substitution in 1995 (CINTRAFOR Working Paper No. 57), providing a
benchmark for softwood lumber use in structural applications in residential
construction. In 1998, a second study by
CINTRAFOR (CINTRAFOR Working Paper No. 73) found that softwood lumber was
slowly losing market share to engineered wood products and non-wood
substitutes. The 1998 CINTRAFOR study
also provided a benchmark for wood and non-wood material usage in residential
decking applications (CINTRAFOR Working Paper No. 78). This research represents the third in this
longitudinal study and will describe the trends in material substitution in the
residential construction industry in 2001.
This study looks at material substitution in structural framing
applications and provides a benchmark for structural panel usage in exterior
wall sheathing, sub-flooring and sub-roofing applications.
The survey results suggest that firm size (based on
annual revenues) within all segments of the industry has increased since 1998,
most likely due to a combination of consolidation within the industry and
growth of individual firms in response to the strong housing market. On a regional basis, small firms represented
a higher proportion of the industry in the southeast (72%) while they displayed
their lowest level in the northeast (49%).
Overall, single family construction represents
approximately 53% of total firm revenues, although this was substantially
higher in the southwest (63%) and somewhat lower in the northwest (46%). Small builders
revenues were evenly split between single family construction and repair and
remodel projects whereas the Top 100 builders focused almost exclusively on
single family construction (providing over 90% of total revenue). In general, large builders had a strong focus
on single family construction (70% of total revenue) but they also derived
substantial revenues from multi-family construction (9% of total revenues),
repair and remodel projects (8% of total revenue) and non-residential
construction (12% of total revenue). The
most dramatic change was observed in the Top 100 builders where the percentage
of revenue derived from single family construction jumped from 58% in 1998 to
93% in 2001.
Almost 40% of respondents reported that their use of
softwood lumber had not changed substantially over the past two years. More importantly, fewer respondents reported
that their use of softwood lumber had decreased substantially in 2001 (4.5%)
than was reported in the 1998 survey(11.8%). The percentage of respondents who reported
that they had used a substitute material in place of softwood lumber in
structural framing applications increased slightly from 98.9% in 1998 to 99.5%
in 2001. The most commonly used
substitute materials were wood I-joists, glue laminated beams, laminated veneer
lumber and reinforced concrete. All of
these materials exhibited an increase in reported use since 1998 with the
exception of reinforced concrete which saw a slight decline in use. The largest increase in use was observed for
finger-jointed lumber, despite the fact that less than 40% of respondents
reported using it. Small decreases in
use were reported for structural insulated panels, wood-steel open web floor
joists and reinforced concrete. The
largest decline in use was reported for TimberstrandTM
lumber, where almost 20% of respondents indicated that their use of this
product had declined in the past two years.
Softwood lumber use in wall and roof framing
applications actually increased slightly in 2001 although it decreased
substantially in floor framing applications.
Softwood lumbers share in wall framing and roof framing increased
slightly to 83.4% and 40.9%, respectively, while it dropped to 38.6% in floor
framing. In header applications (a new
category in the 2001 survey), softwood lumber had a 71.9% share while laminated
veneer lumber had a 20.4% share. The
survey data also suggests that the share of steel in structural framing
applications declined across all end-uses:
to 6.6% in wall framing, to 1.7% in floor framing, and to 1.7% in roof
framing. This data strongly suggests
that the steel framing system was used in less than two percent of US housing
starts in 2001.
Substitute materials were again perceived by survey
respondents as being more environmentally friendly than softwood lumber,
continuing a trend established in the 1995 and 1998 surveys. This continuing misperception on the part of
residential builders is troubling.
Builders were asked to rate the importance that a
broad range of structural softwood lumber attributes had on their material purchase
decision. The average attribute
importance ratings were virtually identical to those obtained in the previous
CINTRAFOR, suggesting that the attitudes of builders toward the importance of
specific lumber attributes have remained relatively constant since 1995. Builders were also asked to rate their
satisfaction with each product attribute.
Although the average satisfaction scores in 2001 were generally higher
than in 1998. Straightness and lack of
defects, the two of the most important lumber attributes, received the lowest
satisfaction ratings. These low
satisfaction ratings suggest that builders remain critical of the quality of
softwood lumber. In contrast, the satisfaction
ratings for price and price stability continue to increase as softwood lumber
prices and price volatility continue to moderate.
A new section on structural panel use in wall,
sub-floor and sub-roof sheathing applications was included in the 2001
survey. While plywood had just over a
50% market share in sub-floor applications, OSB dominated in wall and sub-roof
applications. On a regional basis,
plywood use was highest in the northwest and lowest in the southwest. With respect to firm size, the Top 100
builders reported the highest use of OSB while small builders reported the
highest use of plywood. Interestingly, there was a substantial difference
observed between the Top 100 builders and the large builders, with large
builders using substantially more plywood than the 100 largest builders. Survey respondents reported that their use of
plywood had decreased between 30-50% across the three end-use applications
while their use of OSB increased between 40-47% across the three end-uses.
In considering a total of nineteen structural panel attributes,
respondents indicated that plywood was generally perceived as having superior
performance relative to OSB. In
contrast, OSB was perceived as being superior to plywood in just four
structural panel attributes: price,
price stability, presence of panel voids, and resistance to delamination. Builders rated resistance to delamination, resistance to edge swelling and resistance to
thickness swell as being the most important panel attributes.
The
results of this research suggest that the pace of material substitution in the
residential construction industry has moderated since 1998. To a large degree this might be attributed to
lower lumber prices, less volatility in lumber prices, and the fact that
builders have become more accepting of the decreased softwood lumber quality
that has been attributed to the younger, faster grown plantation resource. The exception to this trend is in floor
framing applications where wood I-joists continue to expand their market share
at the expense of softwood lumber. The
most troubling result is the continuing misperception among residential
builders that softwood lumber is the least environmentally friendly
material. This result could have serious
implications for the forest products industry in the future as green building
programs become more prevalent and home buyers become more assertive in
demanding that environmentally friendly materials be used in building their
homes. This misperception clearly shows
that further research is required to determine the basis for this misperception
and to identify strategies to ensure that information regarding the positive
environmental benefits of using wood relative to non-wood substitutes is
effectively communicated to home builders and home buyers.
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