Eeeewwwwww!

Straw Boss · Dec 30, 2014

Ok, soooo....it seems that whenever it gets below zero around here, the sewer vents on the roof tops of my house ice over as the warm moist air hits the cold air. Just the last five inches or so above the roof line. Sewer gas (rotten egg smell) then backs up into the house. How do I fix this? My plumber has no idea. Lumber yard has no idea. Menards said they used to have some kind of bucket that sits over it to insulate and protect from the elements but haven't carried them in years so couldn't show me what it looks like. Anyone else have this problem and know how to fix it? Not to thrilled about climbing to a second story rooftop in the dark at -11 below temps to knock the ice off of them tonight, let alone having to repeat said procedure a few more times until March.

Anonymous-0 · Dec 30, 2014

(quoted from post at 05:12:51 12/31/14) Ok, soooo....it seems that whenever it gets below zero around here, the sewer vents on the roof tops of my house ice over as the warm moist air hits the cold air. Just the last five inches or so above the roof line. Sewer gas (rotten egg smell) then backs up into the house. How do I fix this? My plumber has no idea. Lumber yard has no idea. Menards said they used to have some kind of bucket that sits over it to insulate and protect from the elements but haven't carried them in years so couldn't show me what it looks like. Anyone else have this problem and know how to fix it? Not to thrilled about climbing to a second story rooftop in the dark at -11 below temps to knock the ice off of them tonight, let alone having to repeat said procedure a few more times until March.

ove further south

Straw Boss · Dec 30, 2014

Your not a big help but I do appreciate your humor. Believe me, if you were sitting here with me right now you might be thinking a bit harder. HA

casecollectorsc · Dec 30, 2014

How do you get the smell??? With water in the traps shouldn't get a smell. As you know, my 24 year old cheap house has never had that trouble no matter how cold. Make sure all traps are full...

IowaJohn · Dec 30, 2014

The water in our basement floor drain will evaporate and then we will get sewer gas in the house. We just pour water thru it every so often and that eliminates it.

jd_adict · Dec 30, 2014

Hey just a thought, this summer I put a hot water tap for outside use. got sick of watchin my eavetrough getting bent and iced up so this winter Im going to hook up my new hot water tap to the garden hose and warm and melt away the ice build up if I get some this year on the troughs.
any way of getting hot water in a garden hose and warm and melt that ice off them vents.?
I would be real concerned about spending the night in the house with uncertain poisonous gasses.
to be honest I dont think I would spend the night there, could be some serious health concerns on this matter. maybe camp over at a neighbours and melt the problem away in the morning. SAFETY FIRST and good luck

charlie n · Dec 30, 2014

Like was said you got a trap issue. Some place in the house you got a open drain.

charlie n · Dec 30, 2014

I hit the post button to quick.A trick I learned a long time ago for drains that don't get used a lot.Pour peanut oil down them.It won't evaporate or coagulate.Basement drains are the worst at drying up.

Jaden · Dec 30, 2014

How large are the vent pipes? Mine are 3" and have never frozen over. Perhaps you need to put a larger diameter on the section above the roof.

retired farmer · Dec 30, 2014

You might try wrapping a short heat tape around the pipe where it is freezing and hook it to an extension cord so you can plug it in.

farmboy48 · Dec 30, 2014

friend of mine years ago had problem with vent icing over in really cold below zero temps used to go in attic and heat pipe just below roof with hair dryer, it worked. But you have to have access to pipe. And power up there.

gab · Dec 31, 2014

I live in N Illinois and it gets darn cold around here and I've never heard of those vent stacks freezing, had trouble with an unused sink trap drying out, a basement drain, and a small hole in a drain pipe in a crawl space and that only would stink maybe once ever 2 months, plumber couldn't find it, I found it after about a year of looking.

4play · Dec 31, 2014

Wax rings on toilets can be bad causing smell, sometimes they will leak fumes out but not water. Also if the vent or vents are blocked then the fumes can "burp" past the traps or siphon out of the traps into the pipes when using water or flushing

I heard wrapping any part of the vent pipe that is exposed to unheated air with insulation can help. Or get a copper pipe as long as you can or at least a few feet, put a tee on one end so it wont fall through the top of the vent and hang it inside the vent pipe. The copper pipe can do a better job of absorbing the heat from sewer gas to help prevent freezing. Since the pipe is hollow it will still allow venting too.

mtny · Dec 31, 2014

Increase your vent to 3 or 4 " . Traps full or not wont matter if they aren't venting.

Straw Boss · Dec 31, 2014

That's right. I can add water to the traps but it only addresses the symptom, not the cause. And there are a total of twelve traps to chase down when I include the washing machine, two floor drains and a sink in the garage. Just not practical to tend to them all, all winter long. Somehow, I need to insulate the vents which is where the trouble starts. I'm also wondering if I had one vent instead of three, if I wouldn't have less freezing because I'd have a more concentrated heat source on the one pipe? My attic insulation is maybe too effective also in comparison to my old house, leaving the bulk of the vent pipe in the attic to remain at a much lower temp? My old house also had a steel pipe vent vs pvc on the new house. Again, no natural heat transfer from the house?

720 lyle · Dec 31, 2014

Easy fix,have fixed many by soldering a tee on copper pipe long enough to reach heated part of building and then dropping it down the stack. The tee needs to hold pipe from dropping in too far. Leave it in there permanently and the copper will transmit the heat up keeping the stack open. I use 3/8 or 1/2 pipe.

Kent Petersen · Dec 31, 2014

i had that trouble to had white pipe replaced with black and the sun takes care of it

showcrop · Dec 31, 2014

Despite some responses I find this difficult to believe as I have heard of this only very rarely, and I have lived in the frozen north for going on 66 years. As others have said either your vent is too small, or you have an open trap. Vent stacks used to be sometimes two inch but for the last probably forty years they have been four inch once they pass into the Unheated attic. Please answer the question. How big is yours in the attic?? You don't need to worry about sixteen traps either, only the one that is in a drain that never gets any water in it. Faaaaaaaaaaaaaar easier than climbing onto your roof!!!!!!

SweetFeet · Dec 31, 2014

Is it an old metal vent pipe?

Ours rusted about shut over time... I don't recall a bad smell - but the toilet really wouldn't flush because it couldn't vent.

Anyway, the plumber and my husband ended up cutting out the old pipe and replacing it with plastic pipe. Problem solved. It is not covered at all... has been that way for 10-12 years.

mkirsch · Dec 31, 2014

The dry trap(s) may be causing your freeze-over problem.

A vent pipe is primarily to allow air IN so your drains operate smoothly instead of gurgling. It should be sucking in cold dry air.

Something is causing a lot of warm moist air to be pushed out the vent.

A dry trap would allow your vent pipe to act like a chimney, pulling warm moist air from the house until it froze over.

If you have a chronic dry trap problem, fill it with RV antifreeze which evaporates much more slowly than water. Or, seal it off.

Ken Macfarlane · Dec 31, 2014

No open traps here but ours freeze over too. I expanded it to 4" and it still eventually freezes over. Insulating the stack to keep it warmer helped alot.

Its a common problem around here in winter during -30 snaps. Once it warms up you hear the chunks of ice falling down the pipe.

old popper · Dec 31, 2014

I have to watch my basement traps more in summer when the central air is on. Dries them out a lot if I don't watch.

redtom · Dec 31, 2014

This happened a half dozen times or so in my folks house when I was still home. The weather had to ne just right, I don't know what the combination was. But dad sent me up on roof with a tea kettle of boiling water. They are 3 in cast iron. Hasn't happened in years and my 3 in pvc don't do it. Basement drains aren't vented.

Wemedeeres · Dec 31, 2014

(quoted from post at 06:28:48 12/31/14) Easy fix,have fixed many by soldering a tee on copper pipe long enough to reach heated part of building and then dropping it down the stack. The tee needs to hold pipe from dropping in too far. Leave it in there permanently and the copper will transmit the heat up keeping the stack open. I use 3/8 or 1/2 pipe.

Ive got the same set up, except I used 3/4 inch pipe. My father in law was the one that told me about it and it works great!

Dr. Walt · Dec 31, 2014

"My old house also had a steel pipe vent vs pvc on the new house. Again, no natural heat transfer from the house?"

Go into your attic and spray the PVC vent pipes with Contact Adhesive & then wrap the pipes with heavy duty Aluminum Foil. Then you would have heat transfer to the pipes from the warm attic air.

:>)

Texasmark1 · Dec 31, 2014

Funny I always thought it was to vent methane gas from the
sewer/septic system. Sure doesn't smell like ambient air.

However, I understand the air replacement requirement. So I guess
it serves two purposes.

Mark

ed will · Dec 31, 2014

Hi, if you think smell is from dry trap just
fill trap with water and a half cup veg oil.
the oil floats and won't evaporate. Ed wil

rd 2N in mo · Dec 31, 2014

Okay, You say that you have more than one vent pipe out the roof. What size do you think they are?

Where does the smell come from, what room? Start with that room and add water to the drain to see if it stops. You have a dry trap somewhere. It should not be the freezing vent/

The moisture has to come from somewhere to turn to frost on the vent. Are your vents at least 2 feet above the roof?

carpenter · Dec 31, 2014

I fixed a couple by adding onto the vent. Especially if the vent is near a valley facing the wind. I think pressure can build up on the roof and force a backdraft. Extend vent to about three feet. Worked for me.

In my case these where new houses and when they froze up it overwhelmed the trap closest to the vent. Also mine where on a septic system.

Straw Boss · Dec 31, 2014

.

Straw Boss · Dec 31, 2014

I had trouble adding text to these pictures so have to start over here. The first picture shows the vent completely iced over. All three are froze identical. After I knocked the top off you can see the build-up on the inside walls. The third picture shows the ice removed and how the pipe is clear once it reaches the shingles or you could say the attic.

To answer a few questions, the pipe is 9 inches high and 3 inches ID. To clarify, I know I have a trap letting the smell in the house, but the traps aren't drying out. The traps are being sucked out because the vents aren't letting air enter the pipe when a toilet is flushed. As the flushings travel to the septic tank, there is a vacuum of air behind it. If the vents don't allow the air in, it then sucks it through the tub or sink trap, taking the water in the trap with it. My son said he flushed the upstairs toilet this morning and the overflow drain on the tub gurgled for awhile.

I think once I can get my roof vents to stay thawed, the traps will take care of themselves and perform as they should.

So back to the vents. Until yesterday, we haven't had sun for 5 days here, and this time of year its only a few hours that its high enough to shine on the vents on the north side of the roof ridge. But regardless, I think I'll paint the inside of the vents black and insulate the outside in hopes the sun will take care of it. Otherwise I like the copper pipe idea. I don't like the idea of electric cords and heat tape on top of the house. Not as a permanent solution anyway.

The only other thought I had was to remove the moisture from reaching the vents in the first place? Not sure how to do that. Maybe a water trap filter in the system somehow like they do with air compressor lines?

All I know is that when six people are in the house this past week, a lot of hot water gets used for showers, hand washing, dishwasher, clothes washer etc. Every time hot water runs to the septic tank, the steam and hot air it creates wants to rise and is reaching the roof vents where it will flash freeze when it hits the cold air.

Thanks to all how answered this post. I appreciate all of your ideas and suggestions.
If anyone can add additional ideas, please do so.
Thanks, Brad

Fatamus · Dec 31, 2014

(quoted from post at 01:01:23 12/31/14) Wax rings on toilets can be bad causing smell, sometimes they will leak fumes out but not water. Also if the vent or vents are blocked then the fumes can "burp" past the traps or siphon out of the traps into the pipes when using water or flushing

I heard wrapping any part of the vent pipe that is exposed to unheated air with insulation can help. Or get a copper pipe as long as you can or at least a few feet, put a tee on one end so it wont fall through the top of the vent and hang it inside the vent pipe. The copper pipe can do a better job of absorbing the heat from sewer gas to help prevent freezing. Since the pipe is hollow it will still allow venting too.

I live in Alaska and we get that if your exhaust is not big enough and extends far enough outside. 4play' are the best ideas so far. The gases will make you sick so you should fix the leak inside which is most likely an empty drain and/or a bad wax ring.

Kirk Grau · Dec 31, 2014

Been watching this today without a chance to reply. My suggestion was going to be that code requires a minimum size (I think 3") to prevent frost closure just as you are seeing so I'm surprised to see that you do have a 3" VTR (Vent Thru Roof). Can't say that I have ever seen anything like that around here.

You are also correct on the dynamics of what is happening once the vent frosts over that the lack of air is creating a vacuum and sucking the water from the traps.

Google Air Admittance Valve. My suggestion after seeing this would be to cut the vents below the roof and use the air admittance valve. Some codes don't allow them, but they would sure work in your situation. If you don't want to have to repair the roof you could probably "wye" into the vent pipe below the roof and put the AAV on that line.

Good Luck,

Kirk

Chris Jones · Dec 31, 2014

I hope you have better luck than I think you will melting away ice with hot water--I've tried and it took a LOT more hot water than I imagined and the hot water cools and freeze up quickly.

Chris Jones · Dec 31, 2014

Air admittance valves or studor vents as they are known here do work and will prevent the drains from sucking dry. They are commonly used here in the case of an island kitchen sink. But IMHO he'll still need a vent in his system for gasses to vent out as there is sure to be some air moving out at some time--at least in a septic tank setup.

Chris Jones · Dec 31, 2014

I think what I'd try is insulating the vent pipes from the time they enter the attic right up to their top outside the house. They might make that Styrofoam pipe insulation that you see for slipping over copper lines big enough--if not you could use 2 or 3 of them opened up and tie wrapped around the pipe. That should be pretty weather proof. Inside the attic you could use about anything you can tape around the pipe as insulation. Point being to keep the air coming out as hot as possible until it's exited.

Chris Jones · Dec 31, 2014

just Google "plumbing vent pipe freezing over".
Lots of advise and an even a Youtube video come up.

Kirk Grau · Jan 1, 2015

The name Vent is something of a misnomer in a typical residential plumbing application. There generally is no need for air to leave the system, just enter to prevent back-siphonage of the traps. One exception is if there might be an enclosed sump pump vented into system. That is about the only type of system you generally would see in most residential use. To my knowledge the only case where an AAV is prohibited is if there is something in the system that will require the system to actually be vented, just don't see anything like this in most residential systems. As you correctly note the AAV will only allow air to enter so you should be cognizant of the restriction.

Kirk

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