You will need to cut the opening to the roof to extend the chimney pipe.
How to install a chimney pipe through the roof.
Make sure to put a bead of silicone around the storm collar where it meets the chimney pipe.
Drill a small hole in this spot to mark the chimney s center.
A single wall pipe will require 18 inch clearance to the ceiling while double wall pipe needs an 8 inch clearance to the ceiling.
Obtain addition sections of stove pipe if necessary.
When calculating your chimney pipe size subtract 1 5 inches for each joint overlap.
A double wall pipe needs a 12 inch clearance space.
Chimney planning step 2.
Determine the number of chimney pipe lengths required the chimney must extend at least 3 feet above the highest point where it passes through the roof and be at least 2 foot higher than any part of the building within a horizontal distance of 10 feet figure 2.
Place the chimney where it would be related to the stove and mark the center of the chimney on the ceiling.
The chimney pipe must protrude through the roof a minimum of 2 feet and it must be at least 10 feet away from the roof line.