Of duct just inside the termination point which is where condensation is most likely to happen.
How to install stove exhaust vent through cold climate roof.
Some passivhaus builders avoid the use of a range hood exhaust fan.
Frost accumulation air sealing drip on outside reduced wall drafts.
Yes you can vent a range hood through the roof using a 6 single wall pipe.
Try to keep it close to the fan location.
On the outside you will see the wind baffle that prevents snow from blowing in.
This approach works best if there is an exhaust grille in the kitchen ceiling far from the range connected to the exhaust port of an hrv.
Here you see a very good roof top exhaust hood made by ventilation maximum in quebec where they tend to make roof vents taller to avoid being buried in the snow.
From up on the roof use a jigsaw or reciprocating saw to cut a 4 in.
More frost cold drafts air sealing figure 1.
Use a regular wall hood if you can go out through the vertical wall in the gable end of the house.
Attempts to insulate the exhaust duct for fans vented through a cold attic and the roof resulted in more frost forming on the exterior portion of the ducting.
Leave the drill bit sticking through the roof so you can find the hole.
Keep the vent low and run the insulation over the duct.
Start in the attic and drill a hole through the roof in the desired vent location.
Use a proper roof top exhaust hood if you must go through the roof.
Rise up into the eve vents of the house and back into the attic fig.
Best practice is to wrap the entire duct with r 3 to r 8 insulation but if nothing else you should at least wrap the 6 ft.