Instructions / Assembly

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Electrical conduits, bolts, and other similar small items must be
removed from the surface of the roof deck; such surface irregularities
cannot be properly insulated and roofed.
None of the foregoing factors is the responsibility of GAF Materials
Corporation, which under no circumstances will assume such
responsibility.
If the roof is sloped
1
/2 inch per foot or more, see “Installation on
Steep Slopes”
NonNailable Decks
Steel Decks
Any of the TRIPLY specifications for use over insulation may be applied
over a steel deck. A steel deck must be covered with rigid insulation which
is firm, capable of withstanding traffic, and is thick enough to span the rib
opening of the deck. The insulation must be mechanically attached using
TRIPLY screws and plates to meet at least FMRC I-60 uplift resistance.
When two layers of insulation are to be installed, solidly mop the second
layer of insulation to the first layer.
A steel deck must be no lighter than 22 gauge and conform to
the recommendations of the latest
Factory Mutual Bulletin I-28 .
Nailable Decks
Wood Decks—Plywood Decks
Wood boards must be at least 1 inch nominal thickness and have
a nominal width of 4 inches to 6 inches. All boards must have a
bearing on rafters at each end and be securely nailed.
Plywood sheathing shall be exterior grade, minimum 4 ply, not
less than
1
/2 inch thick. Plywood decks must be designed and
fabricated in accordance with the recommendations of the American
Plywood Association. All four sides of each plywood panel shall bear
on and be securely nailed to joists and cross blocking between joists.
“H” clips are not acceptable. Plywood decks must be installed with a
1
/8" -
1
/4" gap between sheets and must match vertically at joints to
within
1
/8".
Wood and plywood decks must be dry prior to roofing. Cover
cracks wider than
1
/4 inch and knot holes larger than 1 inch with
securely nailed sheet metal. When light metal wall ties or other
structural metal are exposed on top of the wood deck, cover them
with a heavy ply of roofing membrane, such as inverted TRIPLY
Mineral Surfaced Cap Sheet, extending 2–6 inches beyond the metal
in all directions. Nail in place before applying the base ply.
If TRIPLY Ply 4 or TRIPLY
FlexPly
™
6 is used as a base sheet
over a wood deck, a sheathing paper is required.
Nail the base sheet through flat metal caps or use nails with
attached 1 inch square or round metal caps that have a minimum
withdrawal resistance of 40 pounds each.
Tape-and-staple fastening systems may be used on wood
d
ecks when they comply with local building codes and agencies
such as FM and UL
Roof Drainage
Proper and adequate drainage of the roof surface is required, and is
the responsibility of those involved in the design and construction of
the roof substrate and supporting structure. GAF Materials
Corporation recommends at least
1
/4 inch per foot slope with proper
grading to and placement of outlets. Guarantees will not be valid for
areas of a roof that pond water. The Company defines “ponding” as
water that does not drain or dissipate from the roof surface within 48
hours after precipitation. Ponding can also result from other water
sources, including improperly piped air conditioning condensate and
steam condensate lines.
Perlite tapered insulation may be used to create proper drainage.
For recommendations on tapered insulations or fills to provide slope
for drainage, consult the GAF Materials Corporation Contractor
Services Office.
Expansion Joints
Separate building units from adjacent units by expansion joints to allow
for structural expansion and contraction. Although requirements may
vary depending on structural and climatic conditions, expansion joints are
strongly recommended. The exact location and number of expansion
joints are the responsibility of the building designer.
Vapor Retarders
A vapor retarder installed to the deck beneath the pre-formed roof insula-
tion is not a part of the roofing specification; its use must be determined
by the architect, design engineer, or building owner.
Asphalt
Heating of Asphalts
ASTM D-312 Type III Steep or Type IV High Temperature Steep
Asphalts should be used to install mop applied TRIPLY Membranes
as well as GTRIPLY Base Sheets and ply sheets.
Field experience has demonstrated that proper temperatures in
the kettle and at the point of application are essential to obtain a
satisfactory roof. Kettle temperatures in excess of those indicated
below may result in changing of the asphalt while temperatures
below specified minimums can result in lack of adhesion. Every
effort should be made to maintain the temperature limitations indicat-
ed below. It is essential
that the foreman of the roofing crew be pro-
vided with an accurate thermometer to check temperatures at the ket-
tle and at the point of application. Prolonged heating, at 500˚F or
more, of Roofing Asphalts may cause changes in their physical
properties which can affect roof membrane
performance and must be avoided. Unless Roofing Asphalt is being
continuously used, the temperature of the kettle should be reduced to
below 500˚ F.
Recommended kettle and asphalt application temperatures:
Steep Asphalt ASTM D-312 Type III
Kettle —Not over 500˚ F
Time of Application —EVT, but not less than 400˚ F
HT Steep Asphalt ASTM D-312 Type IV (High Temp.)
Kettle —Not over 500˚ F
Time of Application —EVT, but not less than 400˚ F
Safety Note: Asphalt should be heated to provide the EVT at the
time of application, but should not be heated above the final blowing
temperature or the flash point of the asphalt.
GAF Materials Corporation supports NRCA’s position of two
EVT’s, one for mop application and one for mechanically applied
asphalt. For mop applications, the optimum asphalt viscosity of 125
centipoise has been established. The optimum asphalt viscosity of
75 centipoise has been established for mechanical applications.
The same asphalt will need to be heated to a higher temperature to
achieve the lower optimum viscosity when it is applied with a
mechanical spreader.
Application of Asphalt
Low density roof decks and insulation material tend to absorb the
bitumen. It is important; therefore, that the layer of bitumen used to
secure either the insulation material to the roof deck or the first ply
of felt in the roof system be applied in sufficient quantity to assure
adequate adhesion.
Interply moppings of asphalt must be applied in a continuous film
and consist of approximately 25 pounds per 100 square feet of roof
area with a tolerance not to exceed 20% plus or minus.
TRIPLY
®
Design and Application Instructions