Grand Bay 40 Direct Vent Freestanding
Page 28
January 2000
VERTICAL TERMINATIONS (cont.)
CATHEDRAL CEILING INSTALLATION
Step 1.
Follow installation Steps 1 and 2 under vertical termination section.
Step 2.
Using the plumb-bob, mark the centerline of the venting system on the ceiling, and drill a
small hole through the ceiling and roof at this point. From the roof, locate the drill hole
and mark the outline of the cathedral ceiling support box.
Step 3.
Remove shingles or other roof covering as necessary to cut the rectangular hole for the
support box. Cut the hole 1/8" (3mm) larger than the support box outline.
Step 4.
Lower the support box through the hole in the roof until the bottom of the box protrudes
at least 2 (51mm) below the ceiling (Figure 18). Align the support box both vertically
and horizontally with a level. Temporarily tack the support box in place through the inside
walls and into the roof sheathing.
Step 5.
Using tin snips, cut the support box from the top corners down to the roofline, and fold
the resulting flaps over the roof sheathing (Figure 19). Before nailing it to the roof, run a
bead of non-hardening mastic around the top edges of the support box to make a seal
between it and the roof. Clean out any combustible material from inside the support box.
Step 6.
Complete the cathedral ceiling installation by following the same procedures outlines in
steps 4 through 8 for vertical terminations.
FIG. 19
FIG. 18
VENTING:
CA
THEDRAL CEILING
