# Excess Moisture in Attic causing Condensation...



## IthinkI'mgettinOld (Dec 10, 2016)

Howdy -

I put a wood stove in last winter and despite all the hurdles and fears of leaking roof, etc..all seemed to have gone well through the first winter. I have been up in the attic several times to check out the situation during hard rains, etc. and have never seen any issues.

Last week we had a heavy wet snow in the upper 30s and then right after it got down into the lower 20s and we've stayed at that. I had a small roof leak from a nail popping up and went on the roof to fix it. While up there I went to give the chimney pipe a once over just to monitor the condition. I suspected non-water tight bead around the storm collar. I went up in the attic to check it out and sure enough a few drops had made it through.

While in the attic I noticed that the plywood all around the chimney pipe is soaking wet and condensation drops could be seen on roofing nails etc. even have some mold starting...so I think it is something that has been happening even since last winter, but perhaps I never went up during colder weather to check it out. I've identified some issues with ventilation on the eaves/soffit areas in the attic and am going to do some retrofitting to improve that. Things that should be done regardless.

While sealing off the storm collar I noticed the shingles around the stove were soaking wet at as well now, which I did not notice the day before when I identified the problem, the rest of the roof is dry. From what I can tell there is no water actually leaking in under the flashing. Perhaps the shingles were still wet from ice melting, not sure...but don't think so since the rest of the roof is dry.

Has anyone else had this problem? I fear that the stove pipe is leaking a lot of heat into the attic and creating the condition. The insulated pipe stays fairly cool even when I have the stove very hot, so I think maybe need to reinforce the attic insulation shield with some more screws and a bead of silicone around where it meets the pipe and on the framing for the ceiling support, none of that is mentioned in the installation instructions though.

Will put some pictures up if necessary, but looking to hear from anyone who has had these issues and worked through it or just may have some insight into the situation. My wood stove saves me a lot as I have unlimited access to great firewood and don't want to settle for using the propane furnace which is terribly expensive, especially after spending the money and time to get it in operation.

Thanks a bunch!


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## DickRussell (Dec 11, 2016)

IthinkI'mgettinOld said:


> ...While in the attic I noticed that the plywood all around the chimney pipe is soaking wet and condensation drops could be seen on roofing nails etc. even have some mold starting...so I think it is something that has been happening even since last winter, but perhaps I never went up during colder weather to check it out. I've identified some issues with ventilation on the eaves/soffit areas in the attic and am going to do some retrofitting to improve that. Things that should be done regardless.
> 
> While sealing off the storm collar I noticed the shingles around the stove were soaking wet at as well now, which I did not notice the day before when I identified the problem, the rest of the roof is dry. From what I can tell there is no water actually leaking in under the flashing. Perhaps the shingles were still wet from ice melting, not sure...but don't think so since the rest of the roof is dry.
> 
> Has anyone else had this problem? I fear that the stove pipe is leaking a lot of heat into the attic and creating the condition.



Well, heat leaking into the attic isn't good, first because it is a heat loss and second because it leads to melting of snow on the roof and possibly ice dams at the eaves.

As to wet plywood, if it isn't leakage from above the roof deck, then my first thought is that it comes from leakage of more humid interior air around the chimney penetration (combined heat and moisture leakage). Correcting soffit/ridge ventilation problems of course will help flush out the humidity leakage, but if there is air leakage then you ought to address that. Use of appropriate foam sealant (orange-colored stuff) around the chimney penetration will help.


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## vinny11950 (Dec 11, 2016)

Well, heat leaking into the attic would not be the cause of your moisture issue.  The issue would be the moist air from inside the house leaking into the attic, hitting the cold surface of the ply wood and condensing as it escapes around the storm collar.  Or you could have a water leak from somewhere around the opening.

Are you running a humidifier in the house?  We have heard stories of people running humidifiers in the winter and having that moisture find its way into the attic and causing moisture issues.

Pics would help.

Anyway, good luck and welcome to the forum.


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## fbelec (Dec 11, 2016)

and bathroom exhaust fans vented in the attic and not outside


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## sportbikerider78 (Dec 12, 2016)

I think it can be quite normal for the shingles around a chimney (on the roof to be wet).  If it has been snowing, snow will hit the cap, melt and run down the side, and settle on the shingles.  Don't worry about that...I see it as a non-issue as long as water isn't getting around your pipe flashing.  

How can you be sure this isn't just a pipe flashing issue?  Why is the condensation just there?


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## IthinkI'mgettinOld (Dec 12, 2016)

DickRussell said:


> Well, heat leaking into the attic isn't good, first because it is a heat loss and second because it leads to melting of snow on the roof and possibly ice dams at the eaves.
> 
> As to wet plywood, if it isn't leakage from above the roof deck, then my first thought is that it comes from leakage of more humid interior air around the chimney penetration (combined heat and moisture leakage). Correcting soffit/ridge ventilation problems of course will help flush out the humidity leakage, but if there is air leakage then you ought to address that. Use of appropriate foam sealant (orange-colored stuff) around the chimney penetration will help.



So the Fireblock you think would be acceptable around the attic insulation shield?


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## IthinkI'mgettinOld (Dec 12, 2016)

vinny11950 said:


> Well, heat leaking into the attic would not be the cause of your moisture issue.  The issue would be the moist air from inside the house leaking into the attic, hitting the cold surface of the ply wood and condensing as it escapes around the storm collar.  Or you could have a water leak from somewhere around the opening.
> 
> Are you running a humidifier in the house?  We have heard stories of people running humidifiers in the winter and having that moisture find its way into the attic and causing moisture issues.
> 
> ...


Thanks for the welcome, We had a kettle on the stove but I have taken it off now.


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## IthinkI'mgettinOld (Dec 12, 2016)

sportbikerider78 said:


> I think it can be quite normal for the shingles around a chimney (on the roof to be wet).  If it has been snowing, snow will hit the cap, melt and run down the side, and settle on the shingles.  Don't worry about that...I see it as a non-issue as long as water isn't getting around your pipe flashing.
> 
> How can you be sure this isn't just a pipe flashing issue?  Why is the condensation just there?



The pattern of the moisture to me does not suggest a leak. There are moist areas on the plywood that are quite far from the chimney, but in general it seems to be the highest area of concentration, thanks for the comment.


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## DickRussell (Dec 12, 2016)

IthinkI'mgettinOld said:


> So the Fireblock you think would be acceptable around the attic insulation shield?



Fireblock would be used to seal the gap between sheet metal fitted around the metal chimney to stop the bulk of air leakage, but not to fill the gap between chimney and any wood framing, where a 2" air gap is required. For more input on this, see this: http://www.greenbuildingadvisor.com/blogs/dept/musings/air-sealing-attic


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## IthinkI'mgettinOld (Dec 12, 2016)

DickRussell said:


> Fireblock would be used to seal the gap between sheet metal fitted around the metal chimney to stop the bulk of air leakage, but not to fill the gap between chimney and any wood framing, where a 2" air gap is required. For more input on this, see this: http://www.greenbuildingadvisor.com/blogs/dept/musings/air-sealing-attic



Great link, thanks!


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