Table 13. Roof cut F, test results.
Moisture
Thermal resistance
content
Thickness
Density
(% of
As
After
TRR
(lb/ft3)
Insulation
(in.)
dry weight)
received
drying
(%)
EPS
3
0.8
0
11.0
11.1
99
EPS
3
0.9
2.2
10.6
10.6
100
Notes:
The two 3-in.-thick layers of EPS tested were cut from a 6-in.-thick layer of EPS insulation.
Another 6-in.-thick layer of EPS was present below. It was very wet, fell apart, and could
not be sampled. Core 11, taken at this location, indicates that it had only 65% of its insulat-
ing ability. A 1-in.-thick layer of perlite insulation was present below the EPS. It was fro-
zen to the deck. Core 11 indicates that it was quite wet and had only 54% of its insulating
ability.
such as EPS. Fibrous glass insulation can be an
On the north it is bounded by a higher wall and,
exception. It wets fast but, on occasion, it can dry
on the south, by an expansion joint that separates
out rapidly. It is probably impractical to try to dry
it from roof A3. Two large penthouses are present
out the wet perlite and EPS insulations in this roof.
on this roof. Ballast has been moved aside in a few
If further studies indicate that much of this roof
places in what appear to be searches to stop leaks.
contains wet insulation, the economic impact of
This includes a portion of the expansion joint
having lost, perhaps, a third of this roof's insulat-
where this roof joins roof A3. That area is shown
ing ability to wet insulation should be determined.
in Figure 28. At least one patch has been made in
that area. The temperature of the freezer below
this roof was 0F.
The on-the-roof nighttime roof moisture survey
ROOF A1
uncovered several dark anomalies on this roof. The
This roof consists of a ballasted EPDM mem-
thermogram shown in Figure 28 suggests that
brane, extruded polystyrene insulation (6 in.),
some moisture may exist directly under the mem-
isocyanurate insulation (3 in.), and a steel deck.
brane at the patch.
The temperature of the freezer below this roof was
Figure 29 shows another area of disturbed bal-
0F.
last. While they cannot be seen in the Figure 29
The daytime visual inspection uncovered no
thermogram, we could see the outlines of indi-
signs of membrane or flashing distress on this roof.
vidual insulation boards during the survey. The
The nighttime on-the-roof infrared survey uncov-
spray painted lines on the photograph mark some
ered only one cold (dark) line where nothing ex-
such outlines. The dot on the photograph is where
isted visually on the roof. Those thermal and vi-
core 18 was taken. Figure 30 shows a portion of
sual images are shown in Figure 26. The dark line
the phenolic insulation core taken here. Findings
was found to be a flush expansion joint hidden
from the four cores taken on this roof are presented
below the ballast. The findings of core 16 are pre-
in Table 16. Core 18 contained wet phenolic insu-
sented in Table 14 and the findings of cut G are
lation. Perhaps moisture entered the roofing sys-
presented in Table 15. Their locations are shown
tem at the place where a patch had already been
in Figure 3. No wet insulation was found. Figure
made (just above the dot in the Figure 29 photo-
27 shows the hole made when taking cut G. As
graph). However, it is also possible that other flaws
shown in that figure, no rust existed on the steel
exist in this area.
deck.
Figure 31 shows a thermally dark area to the
This roof is in excellent condition.
west of the west penthouse on this roof. The pho-
tograph and the thermogram were taken from roof
A1, which is about 9 ft (2.7 m) higher. Core 17 was
taken in the middle of that dark area. As indicated
ROOF A2
in Table 16, core 17 contained wet phenolic insu-
This roof consists of a ballasted EPDM mem-
lation. We did not remove ballast in this area to
brane, phenolic insulation (6 in.), and a steel deck.
search for the membrane flaw through which that
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