My stovepipe is causing ice dams!

[Desmond]

Never had this problem until I had my stove professionally installed three years ago. When snow accumulates on the roof, the heat from the stovepipe section in the attic heats up the roof and melts the snow. The result is an ice dam, my question is what should I do to fix this? The pipe is all insulated and installed to code. There is about three feet of pipe in the attic of my house, and its an unfinished non heated attic.

 

[cantoo]

Sounds like you don't have enough roof vents. The heat shouldn't be in the attic space long enough to melt and snow on the roof.

 

[Desmond]

Sounds like you don't have enough roof vents. The heat shouldn't be in the attic space long enough to melt and snow on the roof.

I have one of those whirly turbine vents at the peak.....the snow melts in a path from where the stovepipe is right up to the vent....

 

[cantoo]

Whirly birds sometimes don't move that much air unless it's windy out. Then I would consider wrapping fireproof insulation around the chimney pipe. Maybe something like what they wrap hot water heaters with? I find it strange that you are losing that much heat off the pipe then.

 

[Desmond]

Whirly birds sometimes don't move that much air unless it's windy out. Then I would consider wrapping fireproof insulation around the chimney pipe. Maybe something like what they wrap hot water heaters with? I find it strange that you are losing that much heat off the pipe then.

I thought about wrapping the pipe with something like that but wasn't sure if it would be up to code.

 

[cantoo]

I would think you would be alright as long as everything was fireproof, use roxul insulation and woven wire. A warm chimney is a good thing anyway.

 

[zogger]

Ya, insulate the pipe better sounds like a logical move, with the proper insulation of course.

Had a similar problem when I lived in the frostbite zone, dang beard and moustache would freeze up from exhalations/condensation/FREEZE. Walk/clank/walk/clank. Ice dam at the nose region as well....

This is decades later and I still remember that..

 

[James Bannister]

The heat shouldn't be in the attic space long enough to melt and snow on the roof.

 

[mga]

my chimney blocks would do the same thing, even tho i have plenty of insulation and venting. i wrapped the blocks with 3 1/2" insulation...problem solved.

my neighbor has the double or triple walled pipe from his stove and he had the same problem, even tho he also has adequate ventilation. we wrapped it with insulation that has foil on both sides....problem solved.

 

[haveawoody]

Desmond,

1 of 2 things are the problem.
You either need more vents in your roof or recently had insulation blown into the roof and whoever did it neglected worrying about blowing it into all the soffits.

Vents are a simple one to add, removing clogged soffits a few day project with a shop vac and acting like a circus performer.

 

[NSMaple1]

An insulated pipe should not give off enough heat to melt snow on a roof (I barely feel any heat holding my hand on our insulated chimney 5' above the boiler), and a properly vented attic shouldn't be capable of holding any heat in winter.

More insulation around the pipe might make these symptoms go away, but there is likely more harm being done than ice dams that you can't see & don't know about if the attic can't vent the minimal heat from an insulated chimney..

 

[Desmond]

Thanks for the replies. Its an old house that has had the same attic venting for decades without any issues until this issue. Standing in the attic I can feel the air moving up to the peak, seems good to me. I'm still unsure what to buy for insulation though, but I do like cantoo's chicken wire idea to hold it in place.

 

[KindredSpiritzz]

you can buy heating tape for gutters, plug them in and they are supposed to keep ice from forming. I have ice dams on 2 sides of my house for some reason that has nothing to do with my stove. I havent tried the heating tape yet to know if it works, but its about $40 for 60 ft. It's on my to do list for someday.

 

[Fred Wright]

If the pipe insulating solves your ice dam issues, good. That said, the roof should have a ridge vent and cap so the attic space can breathe. Your home will be cooler in summer.

 

[mga]

An insulated pipe should not give off enough heat to melt snow on a roof (I barely feel any heat holding my hand on our insulated chimney 5' above the boiler), and a properly vented attic shouldn't be capable of holding any heat in winter.

More insulation around the pipe might make these symptoms go away, but there is likely more harm being done than ice dams that you can't see & don't know about if the attic can't vent the minimal heat from an insulated chimney..

you're correct about the insulated pipe.

we did "shoot" his pipe (the one i mentioned above) and with a fire going it was only 50 degrees (46 outside temp, so not bad at all) however, his problem was where the pipe penetrated the ceiling. there was just a sheet metal square flange type thing there, and that's where he was getting his heat in the attic. we insulated that and, while we were at it, we wrapped the rest of the pipe. he bought fireproof insulation which was recommended.

why some one would have used that particular ceiling flange is beyond me, but it was installed years ago.

 

[Desmond]

If the pipe insulating solves your ice dam issues, good. That said, the roof should have a ridge vent and cap so the attic space can breathe. Your home will be cooler in summer.

Yes I'm planning to insulate the pipe this weekend and perhaps a couple more roof vents, as well as check all soffit vents for blockage. I actually have heat tracer tape in my gutters that don't get the sun and they work well....but its not really a solution to the real problem in this case with the stovepipe

 

[haveawoody]

Desmond,

I bet you find it's the soffits are clogged with crud.
Most homes have pretty poor soffit ventilation, most have just a few vented soffits and most of them are semi clogged.
A quick cleanup of them usually makes a world of difference to a hot attic and world of difference to a dusty musty home smell.
Adding a couple new soffit vented panels is also an option that is much easier than adding roof vents.

A quick way to tell if the attic has poor ventilation is pop your head up into the attic and take a deep breath through your nose.
If it has a musty smell or is well above outdoor temperature then your on the right track and can fix it in a number of semi easy ways.

Lack of insulation can also cause a warm attic so while checking the air in the attic have a look around at it's quality.

 

[NSMaple1]

you're correct about the insulated pipe.

we did "shoot" his pipe (the one i mentioned above) and with a fire going it was only 50 degrees (46 outside temp, so not bad at all) however, his problem was where the pipe penetrated the ceiling. there was just a sheet metal square flange type thing there, and that's where he was getting his heat in the attic. we insulated that and, while we were at it, we wrapped the rest of the pipe. he bought fireproof insulation which was recommended.

why some one would have used that particular ceiling flange is beyond me, but it was installed years ago.

OK - that makes some sense. That would be more of an airsealing/insulation problem.

Stack effect with gaps in air sealing on the ceiling can blow a lot of warm air through from the heated space into the attic. It can be pretty significant. Could be warm air from the house rising right up the outside of the chimney, then continuing up to the peak. Either way, a sign of further issues both in air insulation/air sealing, and attic ventilation. If things are really all-OK, the attic space will be the same temp as it is outside in the winter. If it's not, things need attention up there.

 

[Desmond]

If the pipe insulating solves your ice dam issues, good. That said, the roof should have a ridge vent and cap so the attic space can breathe. Your home will be cooler in summer.

Yes I'm planning to insulate the pipe this weekend and perhaps a couple more roof vents, as well as check all soffit vents for blockage. I actually have heat tracer tape in my gutters that don't get the sun and they work well....but its not really a solution to the real problem in this case with the stovepipe

Desmond,

I bet you find it's the soffits are clogged with crud.
Most homes have pretty poor soffit ventilation, most have just a few vented soffits and most of them are semi clogged.
A quick cleanup of them usually makes a world of difference to a hot attic and world of difference to a dusty musty home smell.
Adding a couple new soffit vented panels is also an option that is much easier than adding roof vents.

A quick way to tell if the attic has poor ventilation is pop your head up into the attic and take a deep breath through your nose.
If it has a musty smell or is well above outdoor temperature then your on the right track and can fix it in a number of semi easy ways.

Lack of insulation can also cause a warm attic so while checking the air in the attic have a look around at it's quality.

Perhaps I should check the soffits before doing anything else. Sounds like a fun Saturday morning job!

 

[haveawoody]

Desmond,

That's what I would suggest as the first place to start.
Think it took me around 2 hrs of being shop vac man to clear all my soffits out so not a long day doing it.
Bit of a pain positioning the shop vac on a steady place then getting the hose down to 3 or 4 soffits then move and repeat.
A cold beer in the attic sure makes the job go faster, or seem faster

I had a similar problem in my house but with musty smell working it's way into the house and snow melting in sections on the roof.
I had very few vented soffit panels on mine and of the 6 or so that actually had small cut holes that matched the vented panels all were clogged pretty bad.
A shop vac and a couple hours of clearing all the soffit debris changed the air quality pretty quick.

Even if yours are venting ok removing the debris will make at least 25% more air flow in your attic and after your day of being vac man that's all you might need to do.
While your in the attic have a look for poorly insulated sections, bathroom and kitchen vent pipes to make sure they are in ok shape and still venting properly.
Just 1 visit to the attic is more than enough

Since then I have changed the entire front and back of the house to vented panels with the soffit plywood cover cut away properly.
Nice thing about changing a non vented soffit panel to a vented one is you can spend 30 minutes doing just 1 or 2 or spend all day doing as many as you like and have no fear of creating a roof leak like a roof vent would.