Re: Mold Prevention coatings applied during new construction
Posted by Greg Weatherman on 9/15/05
You raise a good point. I forgot about noble metal reactions. The
metal joints in engineered trusses are anodized zinc coated. This means
they carry a negative charge to inhibit rust and to some degree -
microbial growth. If you understand the process, any sealer with a
quaternary ammonium or cationic (positive charge) will weaken the
strength of the metal connectors.
If you look at the chart on the link I provided, siver is very
nonreactive and usually anionic (negative charge) which is why I prefer
anionic silver based paints and sealers if I use one - which is
Fairfax County VA building engineers showed how the new pressure treated
lumber (not CCA) required triple zinc coated joints or the joints would
fail. Zinc is highly reactive compared to silver.
The paint manufacturers are walking into class action lawsuits wiht
their claims. I have heard some really outlandish claims by Foster's and
I'm sure others will follow.
BTW, the French Quarter of New Orleans has seen a lot of water over 300
years with no magic paints or sealers while fighting termites. They also
used metal flashing with tar instead of plastic or vinyl flashing.
Sometimes, building it right makes the most sense.
aerobioLogical Solutions Inc.
Arlington VA 22202
On 9/08/05, Dennis wrote:
> I am also a builder and would not recommend the use of American Mold
> Guard. Out truss engineer sent out a letter stating that the AMG
> blasting is corrosive to the truss connectors. They reccommended the
> use of Microshield ES. We have been using the Microshield mold
> pretreatment and have been very happy. Check them out for yourself at
Noble metal chart
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