# SmartVent with ice dams and mold



## rlamik (May 1, 2011)

Join Date: May 2011
Posts: 1 









*Mid Roof Smart Vent and ice dams*


I had SmartVents installled on my roof last year. I also have a Cobra Ridge vent, two 30" gable vents, as well as soffit vent baffles to allow my old soffit vent to breath. I installed a whole house fan with a temperature gauge to help during the summer. The very first storm we had with accumulative snow and rain I ended up with an ice dam on the back side of the roof (north facing). The ice/water went thru the SmartVents and soaked my sheathing. I now have a major mold problem. The contractor is saying the products aren't defective and that they installed them properly. What happened? What should I do next?


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## Ed the Roofer (Jan 27, 2007)

Did they install Ice and Water Shield over the Smart Vents?

Ed


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## handy man88 (Jan 23, 2007)

Do you have more than adequate attic insulation?


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## rlamik (May 1, 2011)

Ed- After reading all your posts, that's what I'm thinking, my contractor didn't cover the vents with the ice and water shield. Is there an easy way to check this?

Although we don't have two feet of insulation in the attic, it's adaquate. We installed it a few years back. And there's no gaps around lighting fixtures and we were careful not to block the old soffit vents and put in the baffles to ensure ait flow.

Only other thing to mention is that the front of the house faces almost direct south and the back side faces north. And that it is a small two story house- 24 by 24 that you can only stand in the middle of the attic.

-thanks


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## Ed the Roofer (Jan 27, 2007)

rlamik said:


> Ed- After reading all your posts, that's what I'm thinking, my contractor didn't cover the vents with the ice and water shield.
> 
> *Is there an easy way to check this?*
> 
> -thanks


Lift up the bottom course of shingles along with the starter shingles and see if any product is installed On Top of the Smart Vent. 

See if it is adhered to the top surface of the vent material, or just nailed/stapled in place, such as the case would be if it were only some version of felt paper.

Ed


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## [email protected] (Nov 17, 2008)

> The ice/water went thru the SmartVents and soaked my sheathing.





> Ed- After reading all your posts, that's what I'm thinking, my contractor didn't cover the vents with the ice and water shield.


You misunderstood Ed. The ice and water will be below/under and also on top of the vent. Leaving the vent open. You can't close off the vent or there is no air flow. 

It's not a good idea to put a hole in the roof right where there may be a possibility of ice dams and pools of water. It would have been better to install better soffit or below/behind the gutter vents.


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## packet04 (Apr 21, 2011)

The best thing for you to do is to hire a professional and let them remove the mold and ask them about what could be the problem that caused your vent to mold or perhaps what could be the problem on your roof.


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## rlamik (May 1, 2011)

Ed-

My original contractor never replied to my requests. After the freak October snow storm where we got 14" of snow my sheathing was wet again. I finally got another contractor over the house to remove the Smartvent in December. We took pictures to confirm the vent was not installed properly. Could you concur this is where the mold orignated from?

-thanks


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## framer52 (Jul 17, 2009)

I dislike your venting system for precisely the reasons you have had. To me it would have been better to not have the vents at all than have the possibility of water intrusion.

Second the mold problem may not be that bad, may just be discoloration from having the water back up through the vents.

Now as far as the ice damns are concerned you are getting too much hot air from inside escaping. that means you need to just pack a lot more insulation creating a hot roof than what you have.

I live in the NE where we get these ice damning situations and on my house I packed it and we still get the damns, a lot less than before but we still get them.


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## MJW (Feb 7, 2006)

I've never done a hot roof/cold roof yet, but I was under the assumption that they use closed cell foam insulation, and a dehumidifier or air exchanger inside.


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## framer52 (Jul 17, 2009)

MJW said:


> I've never done a hot roof/cold roof yet, but I was under the assumption that they use closed cell foam insulation, and a dehumidifier or air exchanger inside.


Hot roof means any roof with no ventilation.


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## ParagonEx (Sep 14, 2011)

It looks like it was installed right. Didn't I&W though.


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## [email protected] (Nov 17, 2008)

The vent was installed ok. It just does not work(as you have noticed with the ice damming). You've got 5/8" opening covered by a fabric filter. Not much air flowing there.
Add 4-5 inches of snow covering it and it won't work at all.

The ice and water shield might have prevented water backing up under the shingles and into the hole in the roof, but it won't stop the water from backing up from the gutter, through and under the plastic vent, and into the hole in the roof.

Air seal the ceiling so no interior air is getting into the attic.
Remove the smart vent and close the slot in the decking.
Install ice and water shield to the decking.http://www.roofingcontractorreview.com/Roofing/Ice-Dams/Ice-Shield-ice-guard.html
Install soffit, or fascia vents under and behind the gutter.
Replace the Cobra Ridge vent with a better product. (gaf airvent 11 or similar)


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## Windows on Wash (Aug 30, 2011)

[email protected] said:


> The vent was installed ok. It just does not work(as you have noticed with the ice damming). You've got 5/8" opening covered by a fabric filter. Not much air flowing there.
> Add 4-5 inches of snow covering it and it won't work at all.
> 
> The ice and water shield might have prevented water backing up under the shingles and into the hole in the roof, but it won't stop the water from backing up from the gutter, through and under the plastic vent, and into the hole in the roof.
> ...


+1

Seen more than a few roofs backed up from Cobra vent and Smart vent is okay but not ideal in most cases.


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## MJW (Feb 7, 2006)

framer52 said:


> Hot roof means any roof with no ventilation.


Only if it's sealed, correct? Fiberglass is not ideal to pack an attic completely with. Just look at our walls with fiberglass. They need fully sealed poly to keep the moisture away from it.

I've seen buildings with insulation and no ventilation. The sheathing rots from within because of all the heat and moisture getting up there. No different than a wall with no poly or air sealing.


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## roofguy (Feb 5, 2012)

Ventilation is a huge problem for roofs especially in the winter time. Most homeowner think mold is created during the summer time but here is good example. During the winter on a cold day someone will take a shower, boil water, have unvented drier basically create steam in the house. Steam rises past the cieling into unvented attic or improperly install ridge vent and soffit vent. The steam contacts the cold roof and freezes. then turns to liquid form when the temperture outside raise or you turn your heat up. This constant process will create mold and other problems. Check out this link on <Company link removed> http://www.ialongobuildingcompany.com/roof-venting-and-condensation-problems/


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## Windows on Wash (Aug 30, 2011)

Link to ridge and soffit repairs and they list cobra vent as a "quality" product?

I am a bit suspect. I have seen way too many issues with that stuff.


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## MJW (Feb 7, 2006)

Windows on Wash said:


> Link to ridge and soffit repairs and they list cobra vent as a "quality" product?
> 
> I am a bit suspect. I have seen way too many issues with that stuff.


Wrong "there" in first sentence also. Should be "their"........ Just sayin' in case that's someone's site.

Seen almost as much clogged venting with Shinglevent II also..... :no:


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## pdXammo (Nov 12, 2021)

The ventilation system is fighting itself. It first needs to be balanced between intake and exhaust. The attic venting is defeating the SmartVents. You should not mix venting modes. The air should travel straight up from the SmartVent to the ridge and out. Any other venting present will defeat the function of the primary venting.


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## Bud9051 (Nov 11, 2015)

Old thread and your concerns about different types of vents is wrong. Others will read this so I'm adding the correction.

Bud


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## pdXammo (Nov 12, 2021)

Bud, I would encourage you to investigate GAF University or other forms of institutional learning about roof ventilation. They explicitly counsel against the mixing of vent types with the exception of intake side vents in the same plane. In this instance, the gable vents could feed the exhaust vents and disallow airflow through the areas where mold is being observed. A design imperative is the flow of cooling and drying air under the entire roof deck.








The Most Common Types of Roof Vents for Attic Ventilation


Here's what you need to know about the most common types of roof vents in order to make smart choices for your next project.



www.gaf.com




In this persons case as air flow is lost at the eave from snow the exhaust likely draws from the gable vents and this stops cooling at the eave exacerbating the formation of ice dams.
The OP's vent's were also not correctly installed but, that wouldn't lead to ice damming. The notch was cut too large and there's no I&W. Neither should matter that much if everything else functioned perfectly but, how often is that true?


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## Bud9051 (Nov 11, 2015)

The references you give are obsolete but explaining that to you would not be possible, you are sold on that thinking. Air in an attic moves by way of atmospheric pressure, the difference between inside and outside, not by convection.

Vents located above the NPP (neutral pressure plane) will function as exhaust vents regardless of their location.

Enjoy
Bud


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