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Ratchye 01-09-2009 12:49 AM

Frozen Vent Pipe
 
Hello smart plumbers,

Due to very cold weather, along with a relatively short vent stack too close to the apex of our 12/12 roof, we have a severely frozen vent pipe. Ugh.

My husband tried today to rope up and get on the roof to poor some water down it and add an extender with a 180 bend to prevent further problems, but couldn't even get a rope over the rooftop with the great pitch. :mad:

It is about 3 stories up....so no going up on the roof w/o a rope. Our neighbors recently had a house fire because they used heat tape on their pipe.... :furious:

Looking for some good ideas as to how best (and safest) to get this unfrozen so we can resume using our plumbing system.

Thanks in advance for any help!!!

Jen

Tom Struble 01-09-2009 01:41 AM

i hear stories of homeowners falling off their roofs all the time
it can be dangerous up there even for a pro
you should hires a licensed plumber let him take the risk
just my opinion

mason 01-09-2009 06:52 AM

Depending on the access you have to this vent pipe on the inside of your house, a strong heater with a built in blower (hair drier) might send enough heat up this pipe to melt away the blockade without any roof climbing being necessary

Termite 01-09-2009 09:01 AM

Have you had an ice storm? If not, I'm not sure how the vent could freeze. You might get into the attic and check to make sure that there is good downward pitch on any horizontal runs of vent pipe because otherwise water could accumulate and freeze.

Marvin Gardens 01-09-2009 10:32 PM

Quote:

Originally Posted by thekctermite (Post 209840)
Have you had an ice storm? If not, I'm not sure how the vent could freeze. You might get into the attic and check to make sure that there is good downward pitch on any horizontal runs of vent pipe because otherwise water could accumulate and freeze.

My thoughts also.

How can a vent pipe freeze???? Usually there is enough warm air going up the there to keep it from freezing.

Ratchye 01-14-2009 01:12 AM

Definitely Frozen!
 
Quote:

Originally Posted by Marvin Gardens (Post 210161)
My thoughts also.

How can a vent pipe freeze???? Usually there is enough warm air going up the there to keep it from freezing.

Well, we live in Alaska, and the last two weeks the temperature has hovered around -25. My husband did make it up on the roof (roped in), and found that there was about 2-3 inches of ice. Interestingly, the layers of ice had formed inside, with concentric rings, much like what you would find on the inside of a tree.

He poured water down it, then immediately put a 2 foot extension on it and topped the extension with two 90 degree elbows, so now the pipe vents down towards the house. The husband then climbed down the roof safely:thumbup: and all has been well. Of course, we've had a 50 degree increase in temps so that will help!

Thanks - Ratchye

majakdragon 01-14-2009 10:36 AM

I have seen this before. Sometimes caused by spiderwebs in end of the vent, and then condensate freezes onto them. In Ohio, even though smaller vent piping was allowed, the minimum for the last 3 foot going through the roof was 3" pipe. This was to prevent the problem you had.

Ratchye 01-14-2009 12:25 PM

Yep - our pipe is 3". I hadn't thought about the spiderweb idea...hmmm....If anyone in colder climates has experienced these problems and has great ideas, please let me know!

Chemist1961 01-14-2009 04:33 PM

I have been reading up because last Saturday nite all 3 of my toilets stopped flushing. There is a heated vent stack on the market, designed and built in Ontario.
I have also read that an extension beyond 8" on the short side is too much and will likely refreeze more easily????. This info was from Central Canada where the temp can hit -55. There are suggestions to insulate your pipe right to the roof line and fully within the attic.
I checked mine by cutting in inside the attic and installing a Fernco coupler for NEXT TIME. Seemd to me if I need to thaw anything I could do it just as well from the attic and a whole lot safer.:yes:but I didn't find any ice , perhaps because I got there too late, mid day Sunday after looking elsewhere for blockage. I'm still searching for answers but flushing again.

Chemist1961 01-14-2009 04:35 PM

Sorry believe it or not IT's Called Arctic Vent by Heatline

johnjohnson1957 01-27-2009 12:37 AM

I live in Montana and yes it does get cold here. I have the same problem with the plumbing vent pipe freezing up. THe vent pipe passes through 8-9 feet of unheated attic space before exiting the roof where it continues another foot or so. So far this winter I have had the vent pipe freeze 4 times. It is the warm moist air in the plumbing vents that gradualy coat the inside of the 3" vent pipes until they are closed and not falling snow that blocks the vent pipes. So far this year I have been on the roof twice cleaning ice out to allow the pipes to vent. Another solution is to pour boiling water down the vent pipe. Problem with these two idea is you have to climb on to the roof. Not a great idea when it is ice and snow covered.

To stay off the roof I cut the vent pipe in the attic space and rejoined the two end with a rubber bushing (available at any big box hardware store) I can now work on ice blockages from the relative safety and comfort of the attic vice being on the roof. I also have wrapped the vent pipe in insulation in an attempt to keep the vent pipe as warm as possible so it will vent rather than freeze up. This has had mixed results in that I have had to clear ice blockages from the vent pipe two more time since cutting the vent pipes. Couple of cautions with this idea. It is important not to allow your plumbing vents to vent into your attic. Doing so will eventually make a mess (moisture freezes and eventually melts in the atic) not to mention do serious moisture damage to your attic framing. Another option along this line is to insert a PVC clean out fitting in the plumbing vent pipe. This way you can just remove the clean out plug and then snake out the ice.

I have heard of inserting heat tape into the vent pipe (something the manufactures don't recommend) but have not tried it.

I have heard of (and tried) inserting a long 1" copper pipe into the vent pipe (you fix a T-fitting on the end and then fix short pieces of pipe to the T to support it on the top of the vent pipe). I assume the idea here is to ensure the copper pipe reacheds into the heated part of the house and then it transmits the heat up the pipe helping keep the vent from freezing. FYI: They did not work or me.

Come spring time I plan to spray paint the vent stacks black. This way they will be beter at absorbing the sun's heat and help keep the vent open. Meanwhile I will continue to make trips tothe attic to bang on the pipes or to snake out the ice out.

I am considering filling a copper pipe with auto antifreeze mixture and then capping it so it is a closed system. Then I'd attach heat tape to it and hang it in the vent pipe. The reason for the antifreeze is to give the pipe some thermal mass to increase the odds it actually hold some of the heat the heat tape produces.

Chemist1961 01-28-2009 05:59 PM

JJ,
Wow I used to live north of you I remember that cold. -50 without the wind, square tires, stirred the stickshift in my 5 speed before I could release the clutch......Seems to me years ago I heard straight antifreeze will also freeze where diluted won't or maybe it boils faster... Don't recall which. Anyway check out the properties before you fill the tube.

joebart 01-28-2009 11:09 PM

Hi all, how about installing foil insulation in the roof rafters in the attic. I am learning that this should keep some of the cold out of the attic and possibly transfer heat from the sun to raise the roof surface temp.

If you insulate the vent pipe you may insulate the pipe from any heat that may be developed within the attic.

Okay just my 2 cents!
Good Luck
Joe

Reilley 01-29-2009 12:03 AM

Quote:

Originally Posted by joebart (Post 221117)
Hi all, how about installing foil insulation in the roof rafters in the attic. I am learning that this should keep some of the cold out of the attic and possibly transfer heat from the sun to raise the roof surface temp.

If you insulate the vent pipe you may insulate the pipe from any heat that may be developed within the attic.

Okay just my 2 cents!
Good Luck
Joe

Ideal attic temperature is close to outside temperature, so insulating as it passes through the attic is not a bad idea.

Why not run a heating cable around the pipe and plug it in when you notice the smell of methane in the house?

I just pull out the ladder and pour some hot water down my vents if they freeze. Works like a charm, although I don't have a 12/12 pitch.

joebart 01-29-2009 08:29 AM

Quote:

Originally Posted by Reilley (Post 221135)
Ideal attic temperature is close to outside temperature, so insulating as it passes through the attic is not a bad idea.

Why not run a heating cable around the pipe and plug it in when you notice the smell of methane in the house?

I just pull out the ladder and pour some hot water down my vents if they freeze. Works like a charm, although I don't have a 12/12 pitch.

You seem to missunderstand what I typed. Please read it again before continuing. Do not allow the vent pipe to vent into the attic. It MUST exit the roof and be at least 18" above the roof surface OUTSIDE of the house!

Using heat tape on PVC pipe will burn down your house in a matter of time.

Insulating the roof rafters with a foil insulation will keep the attic at a warmer temp than the outside during the winter time and cooler in the summer. The heat within the attic will keep the vent pipe warm enough to possibly stop it from freezing during those cold months.

So when you climb onto your roof full of ice with a bucket of warm water and make your way across the slippery roof you don't think how dangerouse that is? You don't think of your family's wellbeing if you were to fall and kill yourself? How about when you finally make it to the pipe and I bet you stick you nose right into that pipe to look deep into it to see where the ice has bulit up. So you see the ice and then finaly pour warm water into the pipe and as you pour the water your nose is still over the pipe and once the ice melts you inhale that huge slug of methane gas as well as other sutff that has been collecting their for days.

Don't you think its better and safer to fix a potential problem once the cause is known? Seems like your looking for your 15 minutes of fame. If you continue this method of going up on the roof I am sure to see the OSHA video of your dead body on the ground with a caption saying "Frozen Vent Pipe Got Him"

Please be safe.


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