Cob: healthy home data

[Shannon C. Dealy]

On Tue, 1 Aug 2000,             wrote:

[snip]
> "At a recent job we switched clays for the finish coat, put out a lot
> of work in one day to get it on the walls, and the next day we were
> surprised to see the wall covered with little white fuzzy spots. We
> hoped they would disappear as the wall dried, but instead they stained
> the wall, leaving the rich color with lots of lighter blotches. Wiping
> it with a borax solution or hydrogen peroxide changed the color and the
> texture... so we redid the wall, adding dissolved borax to the
> plaster. Had it been summer, when we could have had better ventilation
> and faster drying, this would not have been such a big problem - but
> that mold was fierce and I think borax would have been necessary anyway.

While I don't claim to be any kind of an expert on molds/fungus, it is my
understanding that they do require organic matter in order to grow, so
presumably it was either the fibers in the mix or some organic 
contamination of the sand/clay that the mold was growing on.  This
person's experience may indicate that even though it seemed to disappear
for me, it may simply blend in with the color of the cob mixes better once
it has dried.  On the other hand, in all the cases that I can think of
where I paid attention to this mold, I believe it ultimately received
quite a bit of direct sunlight, which may have had some relationship to
it's disappearance.

> 
> "Mold spores can come in with the dirt or straw. Use clean chopped
> straw and try changing your dirt if you discover mold. Ventilate
> well. Adding borax or lime to the mix will kill molds. If you develop
> mold when plaster is on a wall, spray it with hydrogen peroxide to kill
> it before adding new plasters."

This should probably be changed from "can come in" to "will", mold spores
are everywhere, it is not a question of if they are in your dirt, straw,
whatever, only to what extent, though different soils and batches of straw 
will probably have radically different degrees of contamination 
(particularly wet versus dry straw).

[snip]
> >After the wall has dried more and loses it's "damp earth" look, the growth
> >seems to disappear.
> >
> >For what it's worth, I have seen similar looking growths (mold/whatever)
> >on the ground around here (Western Oregon)
> 
> (Sarah here)
> 
> Shannon- 
> 
> Was it long white fuzz? which grew in a matter of hours? (I encountered
> mold of the same type in both the northern and southern hemispheres, in
> humid climates. It vanished very quickly, when exposed to sunlight. I've
> never seen it growing on anything other than cob.)
> 
> Sarah
> formerly at sarahm at erols.com

Yes it was long white fuzz that would grow in a matter of hours
(usually overnight).  Aside from seeing it on the surface of the
ground, I have seen a similar (though it's appearance is not identical)
growth just below the surface of the ground when I am digging around here.


Shannon C. Dealy      |               DeaTech Research Inc.
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