Interior Mold on all surfaces

I’ve been contacted by an old lady who is building a log home for help. The house is located in Arkansas.

Her logs (12 inch rounds) were left completely exposed for 10 months while her contractor slowly built the home. He finally got to dry-in this winter and turned on propane heaters.

The logs immediately turned black with mold.

The contractor has told her that he’s applied a “BRAND NEW” EPA Approved mildecide for interior use. He told her it’s so nontoxic that you could lick the stuff but it kills the mold. It is not bleach.

He says that he has applied oil to the interior logs twice to displace the water in the logs.

He is now sanding and intends on applying a waterbased stain and top coat.

Are you aware of a newly approved interior mildecide?

Will oil displace water in logs?

Can you apply waterbased stain and top coat on top of a log that has been oiled?

I’m thinking he’s telling some whoppers to this old lady.

He could be referring to Modec 500.

Non-Toxic to humans but lethal to mold. Same chemical used to remediate Anthrax a few years ago at the Capitol and US Post Offices.

It may be a sap-stain. black and stringing along the timber?

Sap-stain no big deal.



I disagree, Sapstain follows ray cells into wood and is not a surface fungi.
-Some oils serve as food for fungi.
-Oil will not displace water in logs as it only penetrates a short distance and because of EPA regulations, will not last very long anyway.
-Adding heat apparently brought logs up to a temperature at which fungi became active.
-Water-base finish over oil is bad.

Contact PermaChink for a proper method or product to address fungal discoloration and for answers about finish bonding problems now that the builder has complicated matters by taking inappropriate measures. The home may require corn blasting and fungicide treatment, or less may do it. Tap that builder with a magic wand.

I talked to my buddy at PermaChink and he told me that he had an almost identical situation recently. Here’s what he found…

It’s not biological… not mold, not fungi.

Heating the interior of the home evaporates moisture from the interior surface of the logs. Because of the moisture gradiant, moiture from the log interior is drawn toward the log’s surface. As moisture moves through the wood it carries with it water soluble materials, mostly extractives from heartwood cells, many of which are tannins. These are responsible for the staining.

If this is the case, it will be very difficult to fix. Why it only happens sometimes, I don’t know.