Comment from a reader: In response to a reader who had a problem about his stack vent freezing in cold weather, which negatively affected the functioning of his plumbing, I received the following:
A trick I tried many years ago: I attached a 90-degree elbow to the pipe (the stack vent above the roof) to prevent not only freeze-ups, but the down drafting of vent odors.
legally dispose of all debris; replace all rotted/deteriorated sheathing to match existing dimensionally; replace the existing stack vent
with pvc extending it 2~above the roof, size to meet code; provide and install a waterproof membrane - 2 courses along the fascia, 1 course along the gable ends, in all valleys and around roof penetrations.
Depending on the situation, the vent pipe may tie into the stack vent above the second-floor fixtures, or it may go directly up through the roof itself.
Perhaps a toilet has been added in the attic, draining into the stack vent and clogging the vent of fixtures below.
Vertically Parted Molds - parting line vent off casting, stack vent
off casting, stack vent
A system of windows located in high and low positions on the exterior walls facilitates natural cross breezes, while stack vents
ensure airflow to interior wards.
Such venting can be accomplished in several ways, including stem vents (body vents), parting line vents and stack vents