Instructions / Assembly
FOUR (4) PLY BUILT-UP ROOFING SYSTEM
NAILABLE DECK
BASE/INTERPLY SHEETS – HOT ASPHALT APPLICATION
General
The following applies to all Tri-Ply
®
Sheets that may be used as ply sheets
or base sheets:
1. Foot and machine traffic on freshly applied membranes with asphalt
must be kept to a minimum to reduce the possibility of asphalt
displacement due to "point applied" pressure. The potential result is
the creation of an area where the asphalt quantity may be too light
to perform the required waterproofing or bonding function.
Workers must stand on the insulation or deck side of the system
and avoid traffic on the freshly laid membrane system for a long-
enough time to allow the asphalt to set up. Do allow the equipment
over, or store materials on, the freshly laid membrane. Asphalt-
dispensing equipment must have balloon tires.
2. For slopes under 1:12, Type III or IV asphalt can be used. Type
IV must be used on all slopes 1:12 and greater. On slopes up to
1/2
:12, Type II asphalt may be used except in Florida, Texas, New
Mexico, Arizona, and California.
3. Asphalt shall be applied in a uniform layer, without voids, at a rate
of 25 lb/square (1.2 kg/m²) ± 20%.
4. Apply asphalt so that a visible, uniform bleed-out of asphalt shows
at the edge of the membrane. Do not allow heavy flows of asphalt
to extend beyond the membrane edge. Heavy, irregular surface
flows of asphalt will make proper application of cap membranes
and surface coatings difficult.
5. In the vent a wrinkle or a fishmouth forms during the application
of the membrane, do not “walk it down” as the memory of the
sheet or felt may cause it to reappear. Fishmouths or wrinkles shall
be sliced open and patched with hot asphalt and additional mem-
branes. Avoid cutting into the plies below the fishmouth or wrinkle
by angling the knife blade to the side.
6. Base plies must be installed with all side and end laps staggered
and offset from previous plies with adjacent end laps a minimum
of 18" (457 mm) apart.
TRI-PLY
®
Design and Application Instructions
BASE SHEET & PLY FELT APPLICATION CHART
* Where necessary to maintain offset between all plies, base sheet and one-ply starter rolls may be
cut to narrower widths to maintain a suitable offset from succeeding courses. Refer to individual
specification installation drawings.
¹ All end laps must be staggered a minimum of 18" (457 mm) from adjacent or underlying courses.
Recommended
Starter Rolls
2
nd
Full-Width Sheet
Side Lap/Exposure
Following Courses
Lap/Exposure
End Laps
1
Tri-Ply #75
®
Base Sheets*
39
3
/
8
" (1 m)
Lap 2" (51 mm)
Exp 37
3
/
8
" (949 mm)
Same
4"
(102 mm)
One Ply
Tri-Ply
®
Ply 4
Two Ply
Tri-Ply
®
Ply 4
Three Ply
Tri-Ply
®
Ply 4
Four Ply
Tri-Ply
®
Ply 4
39
3
/
8
" (1 m)
Lap 2" (51 mm)
Exp 37
3
/
8
" (949 mm)
Same
6"
(152 mm)
39
3
/
8
" (1 m)
Lap 21 " (551 mm)
Exp 17
11
/
16
11
/
16
" (449 mm)
6"
(152 mm)
13
11
/16" (348 mm)
39
3
/
8
" (1 m)
26
1
/
4
" (667 mm)
Lap 21
11
/
16
" (551 mm)
Exp 17
11
/
16
" (449 mm)
Lap 26
15
/
16
" (684 mm)
Lap 20
11
/
16
" (525 mm)
Exp 18
11
/
16
" (475 mm)
Exp 12
7
/
16
" (316 mm)
6"
(152 mm)
9
7
/
8
" (251 mm)
19
11
/
16
" (500 mm)
29
1
/
2
" (749 mm)
39
3
/
8
" (1 m)
Lap 31
1
/
2
" (800 mm)
Exp 7
1
/
8
" (200 mm)
Lap 30
1
/
16
" (763 mm)
Exp 9
5
/
16
" (236 mm)
6"
(152 mm)
Tri-Ply
®
Ply 4
Tri-Ply
®
#75
Base Sheet
6