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Frozen/Clogged Septic Vent Pipe

KindaHandy's picture

Hello,


My parents live in northern Wisconsin and called me looking for a solution to a problem related to the vent pipe that sticks through the roof of their two story house that vents the main stack in the house.  With recent temperatures at -20 F the vent pipe has clogged due to the formation of ice around the opening of the vent pipe.  Their solution was to climb up two stories on a ladder and knock the ice off with a broom handle.  I'm hoping to keep my parents around for a while longer and was looking for a better and more permanent solution.


Searching the internet I came up with wrapping the vent pipe with insulation in the attic, purchasing a special heated (expensive) roof vent, or wrapping deicing cable around the roof vent.


Does anyone have any other suggestions, or can you weigh in on the ideas I was able to find so far?


Thank you in advance.

(post #76172, reply #1 of 9)

I live in similar temps, and I've never heard of a vent pipe that wasn't totally outside freezing like that when it's only twenty below. Hell, that's when we shuck our vests and thermal underwear. Even my bathroom clapper vent thaws when the vent fan has been on a few minutes. Sure they don't have a partial clog down below?

(post #76172, reply #2 of 9)

Does code there allow a one-way valve in the attic (in addition to a vent stack out the roof)? I had never heard of them until my brother in Nashville told me about them. Some places don't require anything but... http://www.plumbingproducts.com/autovent.html


Dave

(post #76172, reply #3 of 9)

You said "septic vent". Is this house on septic tank or city sewers? If septic tank, is there another vent for the tank itself, or is this the only vent? Only one vent for the entire house?


So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #76172, reply #4 of 9)

The stack vents a septic tank for the house.  And there aren't any clogs below the roof line.  The ice build up is visible from the outside and doesn't lead me to believe anything else would be causing the problem.


The clogged vent pipe has caused the sewer gas to start to come into the house.  Opening the windows to ventilate the house, and climbing onto a roof at these temperatures, are things I'm hoping to help them avoid.


Any solutions would be greatly appreciated.


Thank you.

(post #76172, reply #5 of 9)

Quick fix is obviously to insulate the pipe in the attic as much as possible, then add heat tape if that doesn't do it.

Longer term, make sure the pipe converts to an inch larger as just below roof level, consider Y-ing the pipe and adding a second vent opening, consider adding a vent at the septic tank or drain field (depends on code).

A Studor vent, of course, won't do any good here -- you need to relieve the pressure that's building up.

You do need to make sure the septic system is functioning properly. How old? How long since it's been pumped?


So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #76172, reply #7 of 9)

Thank you for responding.  The septic is functioning properly and was pumped within the last year.  And I think the diameter of the vent pipe is 2".


Thanks again.

(post #76172, reply #9 of 9)

Yeah, 2" is way too small.


So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #76172, reply #6 of 9)

Minimum size for a roof penetration vent in my area is 3". You haven't  mentioned the size your dealing with. Some of the manufactured housing brought in only has 2".

(post #76172, reply #8 of 9)

IMHO wherever the  septic tank is it must have a vent in it . it must be a sginificant distance from any opening (window door etc) for the house. old old ones may not have one, should still get one. the main vent for a house should be 4" all others can be 3"


while your up there breaking ice look at the flashing. see if it can accomidate a larger pipe, most can.  then just cut the pipe back 2'+- and couple on a bigger pipe.


if the flashing looks all "tarry" keep breaking ice till spring lol