# Soffit vent issue



## [email protected] (Jan 21, 2012)

<P>Soffits pouring 3in wide x 1ft ice. Brown in color. New standing seam roof vented with ridge vent and gable. looked in attic at underside of roof decking. color black and wet. Mold look. Could not find bathroom or kitchen vents going into attic. Any ideas?</P>


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## WindowsonWash (Nov 30, 2011)

Heat loss, venting, air loss, etc?

Pictures?


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## 4 seasons (Dec 31, 2009)

Pictures would help, but honestly I'm having a tough time understanding what you said.


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## [email protected] (Jan 21, 2012)

I apologize for not being more clear. The house has a brand new standing seam roof with a ridge and gable vent. There is now ice hanging from the soffits. In looking in the attic i found a black wet moldy look to the entire underside of the decking. I looked for vents going into the attic from the bathroom and kitchen with no evidence of either. The owner wants me to put a new roof on insisting the standing seam is the problem. My thought without looking as to where the kitchen and bath vented was possibly in the walls somehow making its way to the attic. There are no vents exiting siding.The new roof encloses 15 feet of the old roof in the attic. shingles and all. Kind of strange. The house is also a late 1900's home. Just looking for ideas.
Thanks


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## WindowsonWash (Nov 30, 2011)

What did you do to the roof that would have changed the venting?

Did you inspect the sheathing prior to the re-roof?

It is very possible that the roof was breathing a bit previously through the shingles. Metal will not make those allowances and you have to account for that and make sure that the venting is spot on in the future.

Any overhang available? Soffits?


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## Interloc (Apr 6, 2009)

was underlayment put on?


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## Pie in the Sky (Dec 21, 2011)

It is a ventilation issue. Not the roof. Shingle roofs don’t breath either so it’s not the metal. Something has Changed if it didn’t happen before. Tell us more. 

Is it only on the North side? If it is it is not likely a lot of moisture
Was any insulation added? Might have blocked the soffit vents
Is there a bathroom vent? if there is not moisture if going into the attic
Is there a Humidifier? it should not be run higher than 20%

I’ve seen this many times before where a Contractor accidently knocked the Furnace Flue off at the ceiling level. If there is a lot of moisture, that is probably the issue. 

If you cant find it and were talking alot of money, it would be best to get a consultant involved.


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## WindowsonWash (Nov 30, 2011)

Pie in the Sky said:


> It is a ventilation issue. Not the roof. Shingle roofs don’t breath either so it’s not the metal. Something has Changed if it didn’t happen before. Tell us more.
> 
> Is it only on the North side? If it is it is not likely a lot of moisture
> Was any insulation added? Might have blocked the soffit vents
> ...


Shingle roofs don't breathe from a technical stand point but they certainly can leak a bunch more air (especially in skip sheathing) than standing seam (mechanically locked) metal.

I agree that it is a ventilation issue but it begs the question what was done to it to throw it off. 

Furnace flue is a good idea to look at as well as the sheathing and how the tear off was done. I have seen gapped sheathing roofs get a bunch of trash in the soffits and block them up that way as well.


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## Pie in the Sky (Dec 21, 2011)

I was not trying to be insulting, I was merely relating my experience with forensic evaluation of condensation in attic spaces. I have never been in a situation where the permeabiliy of the roof shingles affected the ventilation of the attic. I guess I could have clarified that if it were previously a code compliant system, meaning Plywood, underlayment and shingles, it did not breath. I will be more clear next time. 

But, Recent testing has shown that Shingle roofs do not breath by design. (even when installed on skip sheathing) Please see The December 2011 issue of _Interface magazine_, Page 12 “Vapor Permeability Provides No Performance Benefit For Roofing Underlayment’s in Ventilated Attics.” The Testing Summary reads: _Each test procedure iteration, repeat testing, test component analysis, and roof system check consistently reinforced the hypothesis that conventional system construction in accordance with manufacturer’s instructions creates a non-breathable roofing system as a weather barrier for attic assemblies. In the same respect that rain water and exterior elements are kept out of the attics by the overlapping construction of the shingle system, interior moisture from within does not escape through the shingles. Incorporating a permeable underlayment layer into the roof system does not improve the system breathability of the roofing system. _

It’s a great study, You should check it out. They actually installed the shingles on skip sheathing just to make sure the plywood didn’t affect the test.


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## WindowsonWash (Nov 30, 2011)

Don't worry. I was not offended in the least and you are obviously a wealth of knowledge.

I tend to agree with you on all the points. Without looking at the roof personally, I was just throwing out all the potential options.

In most cases, a steel roof will keep more moisture and have less condensation as a result of the lessened solar vapor drive.

It will usually have a lesser roof deck surface temperature due to increased emissivity, solar reflectance, and lessened thermal mass but if the venting isn't right, you are going to have problems regardless.

As you have clarified, an overwhelming majority of moisture issues are venting related.

Ice damns are venting related but more specifically a heat/air loss issue.


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## Pie in the Sky (Dec 21, 2011)

I just try and keep up to date and have to rely on research because alot of what I observe ends up in the courtroom. And in all reality if I were diposed and asked "Is it possible that air and moisture leaked through that roof?" I would have to say yes. But with real world research I can say Not likely and I can back it up. SO I read ALOT of industry stuff. I also do my own testing, we have a lab here at my office, We even have a hail gun, its pretty fun. We do it all... 

Whats the status on this one Seeya??? My money was on furnace pipe...


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## WindowsonWash (Nov 30, 2011)

I think you are probably dead on with flue pipe theory.

I will be interested to see the story follow up as well.


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