mold in attic from whole house fan

Q: Should I run the Fan after killing the attic mold?

I have mold in my attic on the sheathing and roof joists, dormers and such. It’s on the north side only. The area is about 1500 sq ft of sheathing and 40 joists.

I have used a whole house fan for 18 years, and just recently found the added moisture I blew into the attic over night caused this attic mold only on the north side.

I’m getting air conditioning installed and will no longer be using the attic fan, so the source of the issue is being corrected. I’m also getting my eve vents opened up to increase air flow

I plan to use the mold fogger with the moldstat plus to kill the mold, and I understand that black color go away eventually ( I am not selling my house, so that would be fine with me.)

Should I run the attic fan, or the whole house fan to speed up the drying process?

Louie from Raleigh

A: Just let things air dry

Louie, you are correct that after treatment with MoldSTAT Plus, the mold color may turn a lighter black or possibly gray and may fade over time. Even though you are not moving, if you wanted to get rid of the mold color immediately, just brush the dead mold off the surfaces.

Regarding the using the fan to expedite drying, it is really your choice. Once the mold killer has been applied, the marginal amount of humidity pulled in from the fan, won’t have an impact on the mold because it will have been killed within the first 10 minutes.


  1. Stephen K