Dow Protected Membrane Roof EN - Manual (Page 20)

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1 9
Membrane Seam
Failure
THE ISSUE
Failures at the seams in
thermoset membranes may
be worse with PMR because
the membrane stays damp.
DISCUSSION
Thermoset membranes (such
as EPDM and neoprene) were
historically seamed with a con-
tact adhesive. Seam failure due
to moisture intrusion or other
contaminant was a concern for
this type of membrane because
the membrane stays damp in a
PMR, potentially resulting in an
increase in seam failure. In fact,
Dow never received a complaint
about this perceived concern.
In today’s EPDM system, a
seam tape is used. This tape has
exhibited excellent performance
and this is no longer an issue.
CONCLUSION
There are no documented
cases of seam failure related to
the PMR application.
Plant Growth on
PMR Assemblies
THE ISSUE
Periodically, plant growth
will occur on PMR and other
low-sloped roofs. Can this be
avoided?
DISCUSSION
At times, grass, weeds or small
trees may grow on both PMR
and conventional roofs. Good
roofing practice should include
a maintenance program that
includes periodic inspection for
this type of growth. Any plant
growth should be pulled out
and, if required, the area treated
with a weed killer.
Roots from plant growth can
sometimes damage the mem-
brane if left unchecked. With a
PMR system, there is less chance
of this happening since the
membrane is protected by the
insulation, fabric and ballast.
CONCLUSION
A preventive maintenance and
inspection program should
include inspection and removal
of any plant growth.
Conditions, Issues and Ratings
S P E C I A L C O N D I T I O N S A N D I S S U E S