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nvrrong 12-07-2011 08:29 PM

Mold in attic after reroof
This summer/fall I had my 25 year old house reroofed and the chimney recrowned/tucked and pointed. After the repair, I've been having a recurring leak around a stone/cinderblock chimney that the roofers been out to fix repeatedly. Changed the flashing twice and mortared the space between the chimney and the roof sheathing. Still having problems.
I am now having a white mold problems large areas of the roof sheating and on the roof trusses in an approximately 800 sq/ft attic. I never have had problems before.
I should have adequate ventilation/airflow with ridge vents, soffit vents, gable vents and an attic vent fan.
The only on ther change is that I added unfaced insulation on top of the old blown cellulose insulation this summer but I did what I could not to block the soffit vents.
Could the small leak and change in roof vent types cause a whole attic's worth of mold?
Suggestions for remediation?
If the problem is with the reroof/chimney, is the roofer liable for remediation?
Advice and suggestions welcome. Thank you!

Windows on Wash 12-07-2011 08:58 PM

Bulk moisture in the attic can create mold and mildew issues.

Was the ridge vent added with this last roof? You seem to have a bunch of different venting strategies going on.

nvrrong 12-07-2011 09:06 PM

I had a hard ridge vent prior. I it was replaced with a soft, Cobra ridge vent. Yeah, I do have a lot of ventilation strategies up there.

joecaption 12-07-2011 09:07 PM

The gable vents should have been blocked off and the roof vent removed when the ridge vent was installed.
Now the airs not being sucked in through the soffits and out the ridge vent washing across the under sides of the sheathing.
All the airs doing is coming in the gable and going straight out the ridge vent, leaving all the rafter bays with no moving air.
There should have been foam or plastic baffles installed before the insulation went in.

nvrrong 12-07-2011 09:24 PM

You may be right but I have had essentially the same venting set-up since I moved in and I presume for some time after that. The roofer just replaced one ridge vent with another.
The soffits do have cardboad baffles installed when the cellose was originally put in. I left space before the baffle when I installed unfaced fiberglass insulation.

joecaption 12-07-2011 09:32 PM

If you go to Lowes or Home Depot and try to find Cobra vent, more then likyl your not going to find it any more.
The reason is it does not alow any where near the air flow and it's a royal paint to install correctly, Compress it to much by nailing it to tight and it's useless.
I had a customer supply all the materials for a job and he gave us Cobra Vent and we ran short. I had to order it from a company 1-1/2 hours away because all my shingle supplyers refused to sell it any more.

Gary in WA 12-07-2011 10:37 PM

I agree. I've posted this twice before in this forum:
Good comment!


nvrrong 12-08-2011 09:08 AM

It seems like with the new Cobra ridge vent replacing the old, hard ridge vent, I have lost outlet capacity and which reduced airflow under the roof and may be causing some condensation issues (along with the moisture from the chimney leaks).

My plan now is to get the chinmey reflashed, remediate the mold and replace the ridge vent with a better breathing ridge vent.

My hope is that the mold can just be sprayed and I don't have to rip off the roof and replace the sheating. That would be pricey.

Thanks for the information!

Windows on Wash 12-08-2011 05:39 PM

Once you remove the moisture and get the attic ventilated, a mildewicide/anti microbial can be sprayed on the mold and it will take care of it.

If it is really bad, you can spray it with C02 under pressure (dry ice blasting) can also be used.

firemedic16 01-08-2012 10:11 AM

I have the same problem, attic was problem free for 17 years, New roof was installed and within 2 years, black mold/ mildew, on north facing side. I installed soffit vents and now I will check the ridge vent type. Can anyone suggest a good mildewcide/ antimicrobial spray that I can use ?
Thanks for your help,

racebum 03-14-2012 02:58 AM

i'll bump this since it's a fairly recent thread. when we do water flood damage the product of choice is microban. if you have a jon don or interlink in your town they sell it by the gallon

i'm also troubleshooting the same issue

oh'mike 03-14-2012 06:02 AM

Frequently ,the soffit vents get blocked when the insulation is increased in the attic---

Can you see light coming in through the soffits?

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