sewer gas vent pipe freeze up

[Genofish]

I have had the sewer gas vent pipe freez up a few times this winter. Not totally froze but enough to restrict the air flow. Any ideas on how to prevent this?

[Roofer]

On the roof?

[deerhunter]

mine too and my dad and brothers we are carpenters and all we can think of only pouring hot water down it cause it does freeze down the pipe too

[delcecchi]

how about wrapping with that heat tape sold to keep pipes from freezing. Or put foam insulation around it. Just thoughts....

[Genofish]

on the roof, looks like a 2 1/2 - 3" pipe or so,

[Roofer]

The fix is to find a way that you desire to hang a smaller pipe (1.5")inside the bigger pipe. Make sure it's long enough to get into the warm air area. This will insulate the pipe and it will breathe through the smaller one when it is frozen.

While you are up there check for ice in other critical areas. Maybe even hire a roofer to shovel it off for you. We have shoveled off a few roofs already because of ice dams. Good time to do it also with warmer temps.

[Genofish]

I could drop a 10' 1.5 pipe down the sewer pipe. I would glue a 1.5 / 3" reducer to keep if from falling thru

[Redlantern]

Last year about this time I suggested to someone with a similar problem that they take a broomstick and knock the frost out, my thinking was that way they can't accidentally drop something down the vent. Well, the guy with the frosted vent pipe used a broom with a screw-in handle and, as luck would have it, the handle came loose and went down his vent pipe. So, keeping that in mind, carefully go up onto your roof, exercising great caution so as not to damage the roof, fall off the roof, or tumble into any powerlines, knock out said frost with something that CANNOT fall down the vent pipe then come back down, slowly. One thing that may be causing the vent pipe to frost up is the length of it above the roof. By plumbing code, it is to be twelve inches above the roof. Anymore than this and the gas will have enough time to cool down and frost up, less than this and a heavy snowfall can cover up the vent pipe. Someone mentioned sticking a 1.5 inch pipe inside of the vent. Not sure what this would accomplish but minimum size for a roof vent in Minnesota is two inch. Sticking another pipe inside would decrease the volume.

[Roofer]

It works, try it. Have done it to many homes. That pipe only decreases the volume when it is frozen. Otherwise it is very minimal.

The pipe must have an air space between it and the bigger pipe, otherwise it doesn't work.

[Roofer]

The other option is to replace the pipe flashing with a lead capped one, but they are ugly. They are usually used on old cast pipes.

[jerk bait]

A couple options that I know work.

1. Paint your vent pipe black or replace it with black pipe.

2. Another trick I've used is to smear grease on the inside of the pipe. Moisture won't stick to the grease.

3. I have heard if you hang a length of copper wire down the pipe this will help though I have my doubts on that.

Hot water is the best way to thaw them out. The "ice" is usually not solid ice but frosty. Do not use a broom handle or anything of the sorts as you can damage the pipe. There are sometimes elbows with in the length of the broom handle and with the pvc being cold it can be damaged easily.

[ib_jigged]

Use 1/2" copper tubing. Make a "T" at the top that will not fit down the vent and let the pipe down the vent as far as you can. The copper will conduct heat from the warmer air further down the vent pipe and will work as a chimney in a way with the "T" at the top.

This works very well.

[lovebigbluegills]

This happens to me once or twice a winter and all it takes is a pitcher of warm/hot water and a ladder. My vent is 2" black plastic. Kind of a pain, but very functional for the very few times it occurs.

As mentioned above, be very careful if you have to get up on your roof (I'm fortunate in that I can reach my vents from the ladder). Also be sure that your ladder is in solid contact with the ground, or better yet have somebody hold it to ensure it doesn't slip out.