I have mold in my attic!! Yikes!! Actually, I don’t think its all that bad, but my wife is freaking out. Let me tell about my situation.

A couple years back I was tired of my bathrooms fogging up during showers so I installed the largest exhaust fans I could. The old ones were 40CFM and I installed 200CFM units in them. A buddy of mine in the insulation industry asked me ‘where do your fans exhaust’. I assumed they exhausted outside the home and when I went to install the new fans, I traced the ducting (buried in loose fill cellulose) about 10 feet and just “assumed” that they connected with some exterior vent. They didn’t. They exhausted right into the soffit.

This spring I went to check out my attic, which I hadn’t been in since I installed the new bathroom exhaust fans and saw mold covering about 60% of my sheathing in my attic. I though back to the exhaust fans and traced out the vent line all the way and that’s when I discovered it was venting into my soffit. That was also the area of the attic where the mold was the worst.
I knew I needed to fix the moisture issue, so I put separate roof vents in for the bathroom exhaust fans, took lots of pictures and let the attic sit over the summer. The mold did not spread anymore. I brought two mold remediators in and both said to replace the sheathing, which is OSB, because it cannot be sanded. I had two roofers come in to quote a tear off and they both told me it seemed like a shame because the shingles were in good shape and the OSB’s structural integrity was fine.

Now with summer ending, I need to do something about this .. Ill lay out my options as I see them.

1. Do nothing
2. Replace the roof
3. Treat the OSB with Concrobium or a similar product.

Some of my thoughts on my options

1. Not an option as I see it, my wife thinks our house has “cancer” and it will spread everywhere.
2. Too much money, but if that’s my only option Ill do it but if I could push this off until before I sell, that would be nice.
3. I like this the best for a few reasons: it’s the cheapest, it would save my roof which is in good shape. I could spray OSB sheathing with kilz or some similar primer after I clean it to cover up the staining.

I am sure I have solved the underlying moisture issue. The venting of the bathroom exhaust fans outside definitely solved the moisture issue and my soffit vents are all clear and unobstructed. I also have determined that I do indeed have the correct number of soffit vents and mushroom caps per my local building code.

I have read just about everything I can get my hands on about mold and talked to many people in the industry about this. The consensus is that if the moisture issue is solved and I have good airflow the mold will not come back. Mold only propagates if the conditions are right (high humidity, the right ambient temperature, no light) and if it hasn’t gone too deep and damaged the integrity of the wood the residual staining is only a cosmetic issue.

Sorry this was so long winded and I appreciate any advice or guidance anyone could give me.

 

Really need some pictures.
Do you have a ridge vent and plenty of soffit vents?
I most case a simple application of Timbor or Boracare will take care of the mold.
Google them.
Or any exterminator can do it for you.

 

Pics are attached.

I do not have a ridge vent.

If I use the anti-mold agents, will that get rid of the staining?

 

Another way to have it professionally removed is they use flaked dry ice. It's called dry ice blasting.

A link to a video:
Dry Ice Blasting - Mold Removal in an Attic on YouTube

 

Can they do that on OSB? The two mold remdiation contractors told me the OSB is an issue.

 

I've been to several sites that say it's ok to clean OSB in that way.

I'm not an authority on it so you need to look up a contractor in your area that does dry ice blasting.

 

Thanks, I'll check that out.