Hello,
Can anyone direct to the right location to learn what these stains are? Is it resin stains or something else? Thanks
It does not look like resin to me. Typically, resin you will see oozing from knots and such.
That looks like something from the outside and between the logs coming into the house.
What was on the outside of the logs in that location? Was there staining, of some sort, recently?
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Nothing out of the ordinary on the exterior. It was pretty dry so it could be old staining
Have to agree with Larry. Resin usually will crystalize. This looks more like wood stain. Was the exterior darker in color? Just wondering if there was seepage somewhere if the exterior had been re-stained.
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If this is the same course as years ago when I took it, it was worth my time.
And here’s a thread dedicated to taking the course:
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I think @msenty may have some info for you
Great course Larry. Because of the number of True Log construction in my area, that was one of the first certifications I got. It’s been very helpful for me and my clients’ have always appreciated the “extra” knowledge that I can share with them.
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“Tobacco juice”, an indication of air leakage, poor ceiling air barrier, and condensation. I believe this comes from ceiling insulation; the mechanism is condensation that forms on non-monolithic air barriers like Kraft faced fiberglass. Glue on the Kraft paper mixes with bulk moisture due to condensation and runs down the ceiling. Typically observed on the top courses of logs, where the vaulted ceiling meets the logs.
I did see it last month on a conventional construction home with an I-joist ceiling with closed cell spray foam insulation. The house tested very tight with a blower door, but the issue was still condensation IMO. I suspect the “tobacco juice” was from glue on the I-joists or possibly the OSB.
I haven’t been able to find anything definitive on the internet, but I have seen this issue numerous times. It’s a cathedral ceiling issue, most often log home.
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Oh wow. Tobacco juice describes it perfectly. Thank you.
Who would be the best contractor to evaluate the problem?
Thanks Mike! I’ll keep this in my “back pocket” when and if I run across it. 
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Find someone with building science training to perform and analyze blower door testing results and infrared imaging. Do an internet search; “energy audit”, “blower door testing”. They should have Building Performance Institute certification as a “Building Analyst Technician” plus infrared certification.
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Thank you sir
“Tobacco juice”; I’ve also seen it when log courses are sealed with oakum, a rope type product with resin. Oakum is used to seal cast iron plumbing pipe, but it was popular in 1930’s log cabins. The issue seems to come about when the log cabin is converted to year round use and is heated full time. Again, IMO, condensation leaches out the resin.
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I get the stains coming from the courses, but what about the checkings?
What about checks? It’s unrelated to “tobacco juice.” It’s a natural condition that happens with all large sized timbers and logs.
Thanks. Looking back at the pics, it first appeared that the checks were seeping. Looking again, it looks like seepage was from the course and into the check.
If ever there was a perfect time for the lick test, this is it.
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It crossed my mind 
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