Green Building Construction Projects in Singapore
significant effect on the mean of green
cost premiums regardless of the building type.
Further analysis based on the
p-value from the TPH test indicated
that green cost premiums were statistically different for medium- and large-scale projects in all three building types,
whereas cost premiums were statistically different for small- and large-scale
projects only in residential projects.
Reasons for Different Cost Premiums
Between Green and Traditional
The one-sample t-test was performed to
determine whether each of the reasons
had a significant effect on the difference
in cost premiums between green and
traditional building projects. Because
a five-point scale was used, the test
value was 3, which is the middle value
of the scale. Table 6 summarizes the
test results as well as the ranking of the
With the analysis result, it can be
concluded that R1, R5, and R6 had the
statistically different means from the
test value of three because the p-values
of these reasons were all below 0.05.
Because the mean of R5 ( 3. 70) was
much greater than 3, R5 had a statisti-
cally significant effect on the difference;
however, because the means of R1 and
R6 were much lower than 3, the effects
of R1 and R6 could not be considered
significant. Although the p-values of R2,
R3, R4, and R7 were greater than 0.05,
their mean values were all greater than
the test value of 3, implying that these
could be relevant reasons for explaining
the difference as well.
The analysis results suggested that
the “high cost of green technologies and
materials” was the top reason for the
difference in cost premiums between
green and traditional building projects. As the design and construction
practices of green buildings grow more
complex, green technologies and materials not only greatly affect the capital
cost, but also affect project productivity
(Hwang et al., 2017; Lam et al., 2010).
Moreover, green materials usually have
higher production costs because these
materials lack the economies of scale
and also require special orders and
manufacturing (Kibert, 2008; Malin,
2000). All the interviewees who participated in the post-survey interview also
agreed with this result.
“High research and development
costs for green building products and
systems” was ranked second, further
contributing to the difference in the
cost premium. New green products and
systems usually require more efforts
in testing and code approvals, which
leads to an increase in research and
development costs (Malin, 2000). “Lack
of required green expertise and infor-
mation,” which ranked third, could
also lead to an unnecessary increase in
cost premiums because the key build-
ing players are unable to utilize green
products efficiently (Malin, 2000).
Additionally, without sufficient green
building expertise, key building players
most probably encounter reworks and
changes because they have difficulty
in complying with the green standards,
leading to an increase in the capital cost
for green building projects (Architec-
ture Week, 2001).
“Lack of government incentives/
subsidies for green building projects”
is not a significant reason. This finding coincides with the results from
Hwang and Tan (2012) in which the
lack of government support (e.g., incentives) is not an obstacle encountered
in Singapore green building projects.
This is most probably because of the
extensive efforts made by the government to support the building industry
in Singapore. “Higher consultant and
designer fees” was not rated as a significant reason, perhaps because it is
not the root cause or a direct reason.
Another possible reason may be that
getting specialized consultants and
designers is not difficult and the cost is
not very high (Architecture Week, 2001).
Comparison of Cost Performance
Between Traditional and Green
Table 7 summarizes the cost performances of traditional and green building projects by project type.
The negative and positive percentages indicate an “under budget” and
“over budget” cost performance of projects, respectively. Using the mid-values
of the four ranges of the performance,
in other words, 27.5%, 22.5%, 2.5%,
and 7.5%, the mean cost growth of the
traditional and green building projects
by project type were calculated and are
depicted in Figure 2.
SN Reasons p-value Mean Rank
R1 Higher consultant and designer fees 0.022 2. 60 6
R2 Lack of required green expertise and information 0.315 3. 10 3
R3 Difficulty in getting green services from contractors and subcontractors 0.5000 3.00 5
R4 Difficulty in getting green resources, e.g., materials, technologies, etc. 0.444 3.03 4
R5 High cost of green technologies and materials 0.000 3. 70 1
R6 Lack of government incentives/subsidies for green building projects 0.034 2. 57 7
R7 Higher research and development costs for green building products, systems, technologies, etc. 0.221 3. 13 2
Table 6: Ranking of the reasons for the difference in cost premiums.