20
Figure 21. Two Vinyl Protectors
For Vertical Terminations -
To locate the vent and install
the vent sections:
Locate and mark the vent centerpoint on the underside of
the roof, and drive a nail through the centerpoint.
Make the outline of the roof hole around the centerpoint nail.
The size of the roof hole framing dimensions depend on the
pitch of the roof. There
MUST BE
a 1-inch (25.4mm)
clearance from the vertical vent pipe to combustible materials.
Mark the roof hole accordingly.
Cover the opening of the installed vent pipes.
Cut and frame the roof hole.
Use framing lumber the same size as the roof rafters and
install the frame securely. Flashing anchored to the frame
must withstand heavy winds.
Continue to install concentric vent sections up through the
roof hole (for inside vent installations) or up past the roof
line until you reach the appropriate distance above the
roof (for outside terminations).
WARNING: MAJOR U.S. BUILDING
CODES SPECIFY MINIMUM CHIMNEY
AND/OR VENT HEIGHT ABOVE THE
ROOF TOP. THESE MINIMUM HEIGHTS
ARE NECESSARY IN THE INTEREST OF
SAFETY. SEE THE FOLLOWING
DIAGRAM FOR MINIMUM HEIGHTS,
PROVIDED THE TERMINATION CAP IS
AT LEAST TWO (2) FEET FROM A
VERTICAL WALL AND 2-FEET BELOW
A HORIZONTAL OVERHANG.
NOTE
This also pertains to vertical vent systems installed on
the outside of the building.