Hi, I went up to our attic to store some items the other day and was
overtaken by the smell of mold/mildew. I looked around on the trusses
and roof planks and they are relatively covered in white/black mold.
Our house was built in 1930. We bought the home 6 mos ago and the
previous owner said he put on a new roof less than a year ago.
He installed some low cost ridge ventilation (the stuff looks like
corrugated cardboard) from Owens Corning (I think). Although, because
of the way our home was built originally, there were no soffits that
are accessible from the attic. The roof line connects to the outer
wall where it meets the floor. The roof then continues past the floor
on the outside of the house and the soffit is below the attic floor.
I think you get the point. So, it's not possible to have soffit vents.
(at least I don't think). There is, however, one window at the end of
the house (typical rectangular colonial approx 25 x 40). I pulled out
the window and installed some plywood and cut out an opening for a
gable vent and a ventilation hole for the bathroom ventilation fan;
which, was originally not piped to the outside and has now been blowing
humid air into our unventilated attic. Now were having fun.
So, my question is, I have installed one gable vent, the house has a
cheap ridge vent system, I have corrected the ventilation from the
bathroom fan to exhaust out of the house, so, should I install another
gable vent on the other side of the building to allow for crossflow or
is this not going to work with the ridge vents?
Also, any mold remediation recommendations will be greatly appreciated.
You might have fixed the issue if you ran the bath vent excessivly in
summer. The mold should have died over the summer if it was just a vent
issue. I would get a garden sprayer maybe 5 gallons of laundry bleach
and spray the mold to kill it. If you dont kill it you wont know if you
did enough to fix the issue. If it comes back you know you need more
venting, If you just leave it the mold will die but all the spores might
cause you issues, so kill it with bleach. Opening the other side sounds
easy enough, are you sure it wasnt open before.
I wish I would have corrected it in the summer BEFORE we got to this
stage. But, I wish I had the winning lotto ticket as well.
Is spraying it with a bleach solution enough, or does it need to be
wiped down also?
You'll need to scrub. Gear up with goggles and a mask, and some long
gloves (Clorox isn't ultra-hazardous but it will make the hands pretty
a stiff-bristled brush, then take a bucket of hot bleach water and
mold away. Open the attic windows and use a fan for ventilation of the
bleach fumes. Don't mix the bleach with anything except water. This
my brother & I removed an assortment of mold from roof joists in a
Two questions: is this a finished attic? Is it insulated, and where? Is
floor insulated, or the roof, or both? As I see it your best course
unfinished attic is to insulate the floor well, with the vapor barrier
toward the living quarters, and make sure there aren't any openings
the tops of the downstairs walls where air can infiltrate, then
Soffit vents would be nice. Is there any opening into the soffit areas
Can you see into them through the spaces between the rafters?
Moving the bath vent was a good move. That will cut down a lot of
You also get moisture infiltration from downstairs, through the walls
floor. Warm, infiltrating air holds lots of moisture. It hits the
roof, cools, and
drops condensation on the wood. Mold grows. The house I was working
was uninsulated except for blown cellulose in the floor, unvented, and
with pink-painted fiberboard. Mold was everywhere, and everything up
damp and clammy with condensation. We insulated the short side walls
roof, using rafter-mates to keep an air space by the rafters, added box
on the roof and gable-end louvers to let air into the eaves. This
cured the mold,
but was only a partial solution - the eaves were partly over the 2nd
making those ceiling areas cold where I'd removed the blown crud in
a few circuits. I should have taken up the floorboards and laid down
Thanks for the replies.
The attic is not finished anywhere. The attic floor is well insulated
but, it does not have a plastic vapor barrier underneath the
insullation. And, no, there is no daylight to the soffits. the
soffits hang off the house. So, the soffit vents are a no go.
My concern with bleach is that it only works on "non-porous" surfaces
and does not kill the mold. I have read in another post by someone who
claims to work in a mold testing lab, that using a quaternary ammonium
compound works. A product that has this compound is called "Steramine"
sanitizer tablets. Has anyone used these before? What concentration
would work best?
I guess I just want to make sure I'm not going to keep having the same
issues after scrubbing this place down.
Don`t scrub, its a waste of time. Bleach kills mold, it will only come
back if conditions allow it to. Mold spores are everywhere but only grow
in the right environment, and for your attic excessive moisture is what
you need to stop. You can`t stop mold spores from re entering, so you
need to vent properly so they don`t grow.
The second reference site has old articles -- the most recent was 2003.
However, I'm an ardent listener of Dr. Dean Edell on TalkRadio. His
reports recent studies (2006) that minimize the effects of mold. It's
is everywhere but really doesn't harm people except in rare cases. Just
another "Mass Sociogenic Illness" that so many of us panic over.
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