Dow Protected Membrane Roof EN - Manual (Page 8)

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**This is an illustration of a typical detail. Responsibility for actual design remains that of the designer.
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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 is required to flashings,
insulation and/or membrane
Overlap all edges a minimum
of 12" (300 mm). If a small piece
has to be used, minimum size
should be 8' x 8' (2.5 m x 2.5 m).
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™
Brand Foam
Insulation
Membrane
Deck
STYROFOAM™
Brand Foam
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**
IMPORTANT: When scheduling
or weather conditions delay
installation of plaza, patio
deck or garden roof PMR
areas, care must be taken to
ensure that dark-coloured
products, such as black plastic
drainage boards (dimple
boards) or dark fabric, are not
placed over the insulation
and then left exposed. Dark-
coloured products can lead to
extremely high surface tem-
peratures, increasing the
potential for distortion of
rigid foam boards.
If STYROFOAM ™ Brand
Extruded Polystyrene Foam
Insulation is already installed,
cover it with a white opaque
polyethylene film to protect it
during the delay. Otherwise,
schedule the insulation instal-
lation for a time when the
entire installation process
can be completed in a timely
manner.