Dow Protected Membrane Roof EN - Manual (Page 9)

®™Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow
**This is an illustration of a typical detail. Responsibility for actual design remains that of the designer.
C
O
M
P
O
N
E
N
T
S
–
F
a
b
r
i
c
8
Components
F A B R I C
Description
Ballast reduction fabric,
commonly known as filter
fabric, is used in PMR installa-
tions between the ballast and
insulation. This water-permeable
material must have proven long-
term weather resistance, be strong
enough to withstand traffic
abuse and prevent displacement
of the insulation under flotation
conditions.
Function
• Prevent fines from penetrating
between insulation boards
• Raft the insulation together
to reduce ballast requirements
• Reduce mechanical damage
to insulation
• Allow easy stone removal if
access required to flashings,
insulation and/or membrane
Overlap all edges a minimum
of 12". If a small piece has to be
used, minimum size should be
8' x 8'.
Slit fabric to fit over any roof
penetrations. Cut around roof
drains and other openings
(Figure 4).
Specification
Apply fabric unbonded and
shingle fashion over the installed
insulation (Figure 3).
Ballast
Filter Fabric
STYROFOAM™
Extruded Polystyrene
Insulation
Membrane
Deck
STYROFOAM™
Extruded Polystyrene
Insulation
Ballast
Filter Fabric
Membrane
Deck
Drain Body Drain Line With
Insulation Wrap
Drain Cap
Exterior Drain Body
Figure 3: Fabric Placement**
Figure 4: Drain Detail With Fabric**