Old Insulation and Mold in Attic

[Kid-A]

I recently bought a house with a small mold problem in the attic. I was told it was the result of improper ventilation, and once I fixed that the mold would basically go dormant - or I could choose to have it cleaned. The mold is on the underside of the roof, and is not very severe. However, when I was up there recently, I pulled back the newer insulation that had been laid down, and found what is shown in the picture below. I was told by an insulation guy that it is old cellulose, and some vermiculite, and that I could just cover it all up with new insulation.

So my question is, is it OK to just cover this up? Or should it be removed? The old insulation appears to be dark, and I'm concerned it could be mold growth. But the insulation guy said it was just dirt. Regarding the vermiculite, his guess is that they removed most of it but didn't get it all.

Regardless, I will be adding proper vents and an attic fan which I believe will help prevent future mold growth.

 

[nealtw]

I see some old water stains and dirt, I don't see anything that looks like mold, The plastic sheeting that appears to be on top of the insulation. Depending on where you live but most times that's a no no. In a colder zone the moisture bearier wants to be under the insulation on the warm side.
And welcome to the site.

 

[Kid-A]

Thanks! Yeah, the guy I had looking at it said that that insulation was installed backwards - the moisture barrier should be on the inside like you said. He seemed to know what he was talking about, it's just good to get some other opinions.

 

[nealtw]

Some of that old vermiculite insulation had asbestos in it so it is best to not touch it. Older houses that have ceilings painted with oil base paint have a vapour bearier of sorts. What you want tio do is plug all the holes from the house to the attic like holes for wiring and plumbing. What venting problems do you have. The mold should be treated with something that kills it. When it drys it will go dormet but the spores will spread with air flow.

 

[Kid-A]

I have no soffit vents or any lower vents at all. Just 4 vents at the top of the roof. Also, my house is a bungalow, and the insulation on the knee walls goes all the way up to the roof, which would block any potential airflow to the upper vents. So I already pulled that down, and I plan on having lower vents installed, and also an attic fan at the top.

So I’ve been debating what to do about the mold. I can have it sprayed with something that apparently kills it and prevents regrowth, but it will still appear moldy. Or, for a lot more money, I can have it completely cleaned up.

 

[nealtw]

Kill it in place, removing it just spreads it around. Can you post a photo of the outside, let's look at soffet vents. With out these vents a fan will do little good and if you have them you don't need a fan.

 

[Kid-A]

I currently don't have any soffit vents - which is probably why there's mold in the first place. I will be adding them very soon.

So, no attic fan?

 

[nealtw]

If you have enough low and high venting, a fan is not usually needed.