[Greenbuilding] mold question

[Bob]

Julie,
Since you are "not handy", you will probably need some help but probably 
not above the informed  handyman or friend who is comfortable with 
drywall repair.  However, if the affected area is fairly small, the 
repairs are not likely to be too hard.  Mostly the strain of positioning 
and securing partial sheets of drywall overhead. (Two layers of 3/8" 
drywall are a lot more manageable than one 5/8" sheet, which is also 
denser.)

If water was dripping from the ceiling lights, it must have been a 
healthy leak.  If you didn't do anything to dry the ceiling space out 
quickly (typically within 2 days), it's not too unusual for mold 
colonies to establish.  Since the water came from above and drying would 
take longer in the enclosed ceiling space, there is likely to be more 
mold the inner face than on the exposed face.  There are several courses 
of action, depending on how much mold there is and how widely it is 
spread.  It sounds  like it is limited to a few spots  now.  Imho, a lot 
depends on whether anyone in the house has respiratory problems, 
allergies, asthma or the like - and whether anyone is feeling any new 
respiratory or mucous membrane irritation.  Again, your inquiry doesn't 
suggest that.   There is a tendency to over-react to mold.  I t can be a 
problem, but it is usually mostly a  symptom of  a moisture problem.  
Correct the  problem, deal with any immediate mold problem and go on.  
Of course, if there is any other indication that the mold is causing a 
problem or is not going dormant once the obvious moisture source is 
removed, it is time to investigate further and get some professional advice.

If the drywall of the ceiling is dried fully and there is no new 
moisture source, the mold will go dormant.  If the ceiling drywall is 
still solid, you could clean the surface of visible mold, paint it with 
a stain sealer, such as shellac or Kilz, and repaint the ceiling.  
However, the mold that is probably growing on the inner face will 
release spore, in response to the stress of losing its source of 
moisture, as it goes dormant.  The fuzzy surface growth may also break 
up and be pick up any air currents through the cavity.  As long as those 
spore and fragments do not mix into the living space air, you probably 
wouldn't even notice.  In most cases you might not even notice if they 
did unless the area of growth was extensive and you were sensitive to 
mold or mold by products.  There are so many types of mold, a few of 
which have been associated with health problems, that it is impossible 
to give specific advice without seeing the conditions and testing.  Even 
then, thee is no official consensus on the mold/health relationship.

The best response, imho, is to remove and replace any drywall that has 
been compromised, either water weakened or shows any sign of mold 
growth.  At minimum, again imho, the folks doing the work should wear 
respirators and clothing that can be washed separately or disposed of.  
The work are should be closed off with drapes to keep debris, airborne 
or otherwise, from being carried into the rest of the house.  If the 
mold is extensive (there are several definitions of that) it is  helpful 
to  keep the work area  slightly depressurized  compared to the rest of 
the house.  In it's simplest form, this is a fan in a convenient 
window.  If you get beyond basic precautions, you have a large problem 
and it's probably time to bring in the professionals (and take out a loan).

The first question is whether the drywall has dried; at depth, not the 
surface dampening you could feel.  Given the closed space, probably 
not.  The next question is how extensive the mold growth is inside the 
ceiling.  Unless this area is visible through the tub plumbing access, 
if there is one, you will need to cut a small hole to get a mirror and 
light in to look. Alternately, someone with non-destructive moisture 
testing equipment could measure the moisture content of the drywall and 
the extent of the dampened area.The best fix is to cut out any drywall 
that was dampened, with a foot or so safety margin, of solid drywall if 
there is heavy growth on the hidden face of the drywall.

If you are certain that the leak is sealed, then you could just clean 
off the spots you see with a rag dampened in a solution of dish 
detergent or household surface cleaner.  It's not necessary to use a 
strong solution or use bleach to "kill" the mold; you would have to 
saturate the ceiling enough to be sure of  wetting through the paper 
facing that the mold is living in.  That would do more damage than good, 
expose you to too much chlorine and might provide enough residual 
moisture to actually support mold growth outside the "kill zone". 

What you see is the "fruiting body", the spore producing part of the 
colony, roughly analogous to the flowering part of a plant.  There is a 
"root system", called mycelia, that has penetrated paper.  It is enough 
to physically remove it, trapped in the damp cloth and dispose of it.  
The detergent is as a surfactant, to increase the "wetting" actionof the 
water.  You need to use minimal water, so you are not re-wetting the 
drywall.

I hope you find this this is useful.
Bob Klahn

>
> We had a temporary leak in our tub drain one day water//
> started dripping from the kitchen lights onto the kitchen floor(below the
> tub). //some mold spots (red/brown dots) on the kitchen
> ceiling. -
> Julie
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