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VERTICAL THROUGH-THE ROOF VENTING
The maximum vertical run of vent pipe is 40 ft. from the top of the fireplace. The fireplace will support a run of a maximum
of 40 ft. Maintain 1" air space clearances on all sides of vents (3" above horizontal runs).
If an offset is required directly on top of the fireplace, two 45
o
elbows may be connected directly to the top of this fireplace
to create a horizontal offset then to run upwards vertically. Doing so will continue to allow the use of the 40 feet maximum
vertical run.
The ML39 Fireplace must be installed by a qualified Mendota approved serviceperson.
1. Place the fireplace in its desired location. Drop a plum bob from the ceiling to the position of the fireplace flue ex-
it. Mark the location where the vent will penetrate the ceiling. Drill a small hole at this point. Next, drop a plum
bob from the roof to the hole previously drilled in the ceiling. Mark and drill the spot where the vent will penetrate
the roof. Determine if ceiling joists, roof rafters or other framing will obstruct the venting system. You may wish to
relocate the fireplace or to offset, to avoid cutting load bearing members.
2. Cut and frame a 10" x 10" opening in the ceiling centered on the hole drilled in Step No. 1.
3. To determine the length of the vent pipe required, measure the distance from the fireplace flue outlet to the ceil-
ing, the ceiling thickness and the vertical rise in the attic or second story and allow sufficient vent height above
roofline. For two story installations, fire stops are required at each floor level. If an offset is needed in the attic,
additional pipe and elbows will be required.
4. Assemble the desired lengths of vent pipe and elbows to reach from the fireplace flue outlet. Ensure that all vent
pipe and elbow connections are in their fully twist-lock position and that inner pipe joints (DuraVent only) are
sealed and are leak-proof. Maintain 1" airspace clearances to combustibles (2" above horizontal runs). Cut a 10"
x 10" opening in the roof, centered in the small drilled hole placed in the roof in No. 1. The opening should be a
sufficient size to meet all clearance requirements. Continue to assemble lengths of pipe and elbows necessary to
reach up through the roofline. Galvanized pipe and elbows may be utilized in the attic, as well as above the
roofline. The galvanized finish is desirable above the roofline due to its higher corrosive resistance.
5. If an offset is necessary, it is important to support the vent pipe every 3 ft. to avoid excessive stress on the elbows
and possible separation. Wall straps are available for this purpose.
6. Slip the flashing over the pipe sections protruding through the roof. Secure the base of the flashing to the roof
with roofing nails and seal flashing to roof. Ensure the roofing material overlaps the top edge of the flashing. Ver-
ify you have at least the minimum clearance to combustibles at the roofline.
7. Continue to add pipe sections until the pipe and the vent cap meet the minimum building code requirements, as
outlined in No. 8 on the following page.
8. For multi-story vertical installation, a ceiling fire stop is required at the second floor and any subsequent floors.
The opening should be framed to 10" x 10" inside dimensions as described in step No. 5.
9. Any occupied areas above the first floor, including closets and storage spaces, which the vertical vent passes
through, must be enclosed. The enclosure may be framed and sheet rocked with standard construction materials,
however, be sure to maintain minimum allowable clearances between the outside of the vent pipe and the com-
bustible surfaces of the enclosure.
10. Height "*H" from roof surface to the top of vent cap can be determined as follows:
Complete installation with storm collar and vent cap.
"H"
DIMENSION
ROOF PITCH
FEET
METERS
FLAT to 6/12
1
.3
7/12 to 9/12
2
.6
10/12 to 12/12
4
1.2
13/12 to 16/12
6
1.8
17/12 to 21/12
8
2.4
