The Log Home Neighborhood

An online log home community for log home enthusiasts.

Problem with log home finishing - need guidance on how to switch from one finish to another product

Hi everyone, new member here.


Let's see, where do I begin?... perhaps with a brief summary, and then the whole story?


Summary: Our 8-year-old house (treated with Sansin) is infested with fungus / mold, and Sansin can't help. We want to switch to Sikkens Cetol (I think), and are not sure how to proceed.


Please bear with me with the long story, I do have some questions (at the bottom), and genuinely need some help.


Long story: built our house 8 years ago, and treated it the right way. The logs were clean to begin with, then we had them pressure washed, and then we sanded the whole house (80-grit with palm-sized orbital sanders) from top to bottom just prior to staining (yeah, we really wanted this to work, and were dedicated). We applied two coats of Sansin stain (Natural 011), then one coat of UV Clear, all in the same season (yeah, we were busy). The next summer, we applied a secod coat of UV clear / stain mixture (4 parts UV clear to 1 part Natural 011). Since then, we had to treat the entire house two additional times because the sheen on the UV clear appeared to be worn out. As the suggestion of the supplier of the Sansin products, each time we used the same 4:1 UV Clear:stain mixture.


Then the horror began.


We initially got black dots here and there, then entire patches of those same black dots. The supplier of the Sansin product was not surprised when we called him, and he said it was just fungus (he himself had to treat his log house for fungus almost every summer, or so he claimed). So he suggested using his recipe: 10% household bleach, applied from bottom to top, then rinsed thoroughly. The problem is that this also took off the sheen of the UV Clear, so we treated the whole house yet again, still with the 4:1 mixture. The next spring, the fungus came back... but worse yet, some of the fungus appears to be thriving *underneath* the UVV clear, which means you can't easily get to it. I have attached a jpeg closeup picture that shows that (as best as I could).


We contacted Sansin, and they were no help at all. They had a fresh-out-of-college girl who contradicted herself every time she consulted her senior colleague, and told us to bring it all the way back to bare wood (!!!) and start over with Sansin products. Yeah right, repeat the same mistake we made eight years ago, which brought us to this hellish situation? Thanks, but no thanks. Insanity is repeating the same gestures over and over again, and expecting different results.


A friend of mine had a log home treated with Sikkens Cetol, he owned it for 23 years, and he applied maintenance coats 3 times total over those 23 years. I have already beat him 3-fold, maintenance wise, in just 8 years with this Sansin stuff.


So my questions are:

1-) Other than killing myself at the job of sanding the whole house again (and it will be worse now because of the sticky UV clear coat), is there an environmentally friendly way to chemically "strip" it or neutralize it, just enough to accept a Sikkens coat? Note that we have a well as water supply so we need to be cautious of what chemicals run off to the ground.

2-) When asked, Sikkens tech support told me I can't apply their product on top of Sansin, and that I first have to bring it back down to bare wood (!!!! again!!!). Does that mean only removing the sheen from the UV clear, or all the way through to whichever depth the Sansin stain has penetrated to? This sounds insane... is Sikkens just being overly cautious for liability reasons?

3-) Is Sikkens the right product to use (after the Sansin fiasco)? I only have a single reference, so any advice would be useful. I think I need to worry about breathability, but the logs are 8 years old...

4-) Do I need any additives in the Sikkens to prevent any future fungus growth? Or any tratment to the logs *before* applying the Sikkens?

5-) I read in a forum that the darker stains are better for fungus protection (and therefore, Sansin's Natural 11, which is a caramel color, was a mistake to begin with). Is there any truth to that, and if so, how dark do I have to go?

6-) I have a neighbour in a log house about 500 feet away, and he does not maintain his house. In fact, it is also covered with fungus. Are fungus airborne? I mean, am I condemned to be permanently attacked by fungus because of this source 500 feet away?

7-) After 8 years, I have to assume that the logs are sufficiently dry that I don't even need to worry about it, right?

8-) Or do I have to hope that lightning will strike and burn the darned thing to the ground so I can build a fake one using Canexel?


Any advice would be greatly appreciated... my wife and I worked so hard for that house, we are heartbroken to see it become a burden. If we could only get over this bad spell, we could start enjoying it again, instead of worrying about how much more work it will represent.


Many thanks in advance,


Views: 5483


Reply to This

Replies to This Discussion

There is not enough information here to even try to guess what’s going on. First off if I remember correctly, there are 2 types of blue stain. One blue stain is the Fungi such as this. The spores of this Fungi is not only air born but they can be carried by birds and by certain beetles and other boring insects. Standing dead (beetle killed) logs are notorious for having this type of blue stain. This Blue Stain Fungi needs 3 things in order to thrive, air, nutrients (food which would be the sugars in the wood) and water. Water can be either liquid or vapor form. Not only will you find this Blue Stain spores in the logs/wood but you will also find it in decorative bark dust and wood chips. Keep in mind that these spores are sticky so they can hitch a ride with just about anything. That’s one reason I always recommend that you wash your house down twice a year, whether you think it needs it or not.

We had 2 log homes in Oregon that were about 500 feet apart. They were built by the same builder with the same species of log. One was covered with this fungi and the other one wasn’t. We stripped it down, applied a 1 to 4 bleach wash to kill the spores and recoated using extra mildewcide. Within 6 months signs of this fungi started showing up again. This time we re-worked the areas in question, trimmed all the bushes from around the home for better air exchange and removed all the bark dust from around the house. We never had any more problems with it after that

With that said, here are some questions that I would need to know. What species of log do you have, are they round or square ? What size are your logs ? What room is in the inside of the infected areas ? What is the distance from the ground to the first course of log. Are there bushes, plants or trees close to the house ? Do you have any bark dust or wood chips spread around your house?

Looking at the one and only picture, it looks like the finish is pretty heavy. One question I would have for Sansin is; How many coats of your product can you apply before it starts to lose it’s ability to breath? Just looking at this one picture, does it have to be stripped? With nothing else to show me, I would have to say yes.

Most of my income today comes from appearing in court as an expert witness concerning lawsuits over log homes. I have heard one to many judges tell a defendant that they were the professional and that they should be aware of their products capabilities and limitations.

This home is not the first home to have problems with a finish nor will it be the last. It seems to me that if the manufacture of any product used in this field or any field as far as that goes really wanted to make their product one of the best, they would solve the problems without trying to guess. If this means going to a home and looking at it in person, so be it, go there, take samples, take them back to the lad and find the right answer. This problem is so big that if you could solve you could be a millionaire within a year.

You ask me what I would do to this home using the little information I have. I can’t give you an answer, I would have to see the home first.

Have a great day.

Jim Bilyeu
Several years ago a friend of mine told me a similar type of a “Horror Story”. He said he was cutting green lumber with his chainsaw and the chainsaw oil was abundantly spilled over the logs. Even though he did immediate cleaning, some time later (as wood extractives surfaced) he noticed dotty blue stained spots right on the locations where droplets of chainsaw oil were spilled. Later on a professional told him that chainsaw oil may contain thousands of nano-sized iron particles that are hard to remove as the oil brings them deeper into the wood, later generating so called “Inky Wood” stain. Roaming through the WEB I incidentally hit the FORINTEC and University of BC page titled “DISCOLORATIONS OF WOOD PRODUCTS”. Page 5 gives more details on iron stain in wood. Here is the link:
Hi Smith Piker, and thanks for that info. I assume you posted about chainsaw oil because of my mention that we sanded the house twice from top to bottom during the prep stage because the builder had splattered our house with chainsaw oil. Again, thanks for the advice, though it does not apply to our situation. The splatter was localized, and we sanded it down thoroughly. We ended up sanding the entire house not because there was chainsaw oil everywhere, but just because in our innocence, we thought the re-sanded areas looked a lot more pale and light than the other areas that had been sanded several days previously.

Furthermore, the fungus started near the second story (areas not affected by the chainsaw oil incident).

Still, useful info to keep in mind. Thanks again.
Dan, You said it started near the second floor. Where would your kitchen and bathrooms be in relation to this area.

Just wondering............

Hmm, the first place I noticed it was the top 3 or 4 logs of the wall on the north-east side (had a door but no windows). Relative to that wall, kitchen is at the other end of the north-west wall, and bathroom is about halfway down the north-west wall. There are no vents anywhere near that north-east wall where we first noticed it.

Note, however, that first noticing it there is no garantee that this is where it first appeared...

OK, here's a couple of things to check. First, check the exterior walls at the bathroom and kitchen areas. Let me know if they have the fungi on them. Second, take a squirt bottle or hose and wet down the exterior walls where the fungi is growing. Watch closely and see if you can tell if any moisture is getting to the substrate of the logs. Is the water soaking in or running off?

I notice you had a moisture meter. Before taking a shower, check moisture content on the exterior wall of the bathroom. A couple hours after taking a shower, check the moisture content again in the same area and see if there has been any change.The spores that you have cannot thrive on less than 18/20 % moisture. This moisture can be in either liquid form or vapor form. If no moisture is getting to the logs from the outside (liquid form) then they are getting moisture in vapor form from inside the home.

Every time you bath or cook, you are putting moisture into your logs.This moisture wants to get out and the only way it can is in vapor form. Now, if your finish can no longer breath for some reason, this moisture is going to be trapped under the finish giving the spores just what they need in order to grow.

It might be interesting to look at these spores under a microscope to see just where these spores are for sure, under the finish or in the finish.................................

One more thing to think about, you have these spores that have to have moisture (water) in order to thrive and reproduce. Now, if oil is used as a carrier in oil base finishes, what is used as a carrier in water base finishes???????

Let me know what you find.....................

Jim Bilyeu
You are absolutely right – I have read your story as well as almost all other contributions published in the forum because (apart from planting flowers) wood is my favourite material. I am studying deterioration of wood with a hope to move into a log home in the future. My previous “cottage” was just a cabin with pine siding boards and I never had mildew problem most likely because the boards did not contain any sapwood. Apart from this, they were kiln dried, so the nutritional materials and resins might have been stabilized or crystallized in the wood.
Also, Mr. Bilyeu recommended you to determine the moisture content in your logs. When my wife was about to plant some tulips she asked me to determine the moisture content in the soil and it was 25% in the top ¼ inch layer but was 260% in the soil taken from 3 inches bellow the ground. Based on this I predict that the moisture content deeper in your wood might be higher then on its surface and maybe the fungus is living deeper in the wood.
Hi Dan, I work for a Log Home builder & He also built my log home, which has a Sikkens exterior finish on it. This is his finish of choice. When he does any log home restoration projects, he uses corn blasting to remove any exterior products, which is a safe and effective method to get back down to the bare wood. My log home is 4 years old and the exterior looks the same as the 1st year that the finish was applied. We've been very happy with the Sikkens product and so have all of our other log home customer's, and we build about 6 homes a year, and are exclusive to the Sikken's product. You should check with Sikkens about additives such as fungucides, or you may need to pre-treat your logs, but I am sure that with today's technology that your problem can be remedied with the proper technical support. I bet that with the right questions asked that you could even get a company representative to come to your home for assistance, maybe:)))) You' ed be surprised what help is availaable when you kindly ask for it. It sounds like you've been through a lot of misguided problems. Good Luck! P.S. I live in WA where it rains all of the time, and our log homes (mine & our customer's do not suffer from fungus issues).
Thanks Diana.

Does your house, by any chance, have jumbo-sized overhangs? I'm sensing and hearing and reading a lot of "blame" on the regular sized overhangs on my house, with statements like "small overhangs mean the walls get wet!". To me, that shouldn't be an excuse for fungus (that's why I treated the walls, to make them stand up to rain), but since you mention it rains a lot in your area, and yet none of the Sikkens-treated houses seem to get fungus...
Hi Dan,

Just checking to see how you are standing in finding a solution to your problem. I would love to talk to you about some of your concerns. I work at Canadian Log Home Supply in Eganville, ON (close to Ottawa). number is 1-800-746-7773. I am not looking to sell you anything you don't want to buy, just try to answer some of your questions and help you not be so confused with all of the steps and products out there. I have also done restoration work on log homes for 22 years, i am sure i have some knowledge that may help you.
Hi Dan, I believe that we have about a 24" overhangs (without checking my blueprints), but we get a lot of driving winds with our rain too. I'll include a pic of my overhangs here.
Take care. Diane
Hi Diana,
I like your pictures as well as your log home. What I see, it looks like there is a considerable amount of sapwood in almost every log and the coating is performing well. Can you please let us know which coating did you use and how old is the structure and the coating. Also, do you know if the logs were kiln-dried before installation or were they just naturally dried (seasoned)? Thanks.


© 2019   Created by Neighborhood Host.   Powered by

Guide to Log Homes | Advertise | Badges  |  Report an Issue  |  Terms of Service