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56131J 17
VENTING INSTALLATION
Continued
4. Connect a section of pipe and extend
up through hole. If an offset is needed to
avoid obstructions, you must support vent
pipe every 3 feet. Use wall straps for this
purpose (see Figure 24, page 15). When-
ever possible, use 45° elbows instead of
90° elbows. The 45° elbow offers less
restriction to the ow of ue gases and
intake air.
5. Place ashing over pipe section(s) ex-
tending through roof. Apply a bead of
silicone or roof sealer to the bottom ange
of ashing and secure base of ashing
to roof and framing with roong nails. Be
sure roong material overlaps top edge of
ashing as shown in Figure 24, page 15.
There must be a 1" clearance from vent
pipe to combustible materials.
6. Continue to add pipe sections until the
height of vent cap meets the minimum
building code requirements described in
Figure 14, page 10.
Note: You must increase vent height for
steep roof pitches. Nearby trees, adjoining
rooines, steep pitched roofs, and other
similar factors may cause poor draft or
down-draft condition (see Figure 24, page
15). Increasing vent height may solve this
problem.
7. Apply a bead of sealer to the upper edge
of ashing collar. Slide storm collar over
pipe and down to top edge of ashing.
Apply a second bead of silicone or roof
sealer around remaining seam of storm
collar. Twist-lock vent cap onto last section
of vent pipe. Finish sealing ange around
roong material with roong sealer.
Note: If vent pipe passes through any oc-
cupied areas above the rst oor, including
storage spaces and closets, you must enclose
pipe. You may frame and sheetrock enclosure
with standard construction material. Make
sure and meet the minimum allowable clear-
ances to combustibles. Do not ll any required
air spaces with insulation.
Figure 27 - Cathedral Ceiling Support
Box Installation
Cut hole 1/8"
larger than
support box when
projected onto rooine
2" minimum below
nished ceiling
Cathedral
ceiling
support box
Level
1. Remove shingles or other roof covering as
necessary to cut rectangular hole for sup-
port box. Mark outline of cathedral ceiling
support box on roof sheathing using the
locating hole as a center point.
2. Cut hole 1/8" larger than the support box
outline (see Figure 27).
3. Lower support box through hole in roof
until bottom of box extends at least 2"
below ceiling (see Figure 27). Align sup-
port box vertically and horizontally using
a level. Temporarily tack support box in
place through inside walls and into roof
sheathing.
4. Using tin snips, cut support box from top
corners down to rooine and fold result-
ing aps over roof sheathing (see Figure
28). Apply a bead of non-hardening mas-
tic around top edges of support box to
make a seal between box and roof. Nail
in place with roong nails. Remove any
combustible material that might be inside
of support box.
5. Complete cathedral ceiling installation by
following the same procedures outlined in
steps 2 through 7 for Flat Ceiling Installa-
tion, page 16.
Non-hardening
Mastic under all
edges of support
box before nailing
Figure 28 - Installed Cathedral Ceiling
Support Box
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