Log Home Restoration - Have You Seen This on Your Log Home?
By Earl D. Johnson
While working around the southeastern United States, I have come across many newer log homes (between 1 and 3 years old) that the finish is not only failing, but the stain looks like it has black specks all through it in some places. I'm not talking about Artillery Fungus. That looks like little dots. These are specks or spots (for the lack of a better description). It is not in just one area, but can be found on all sides of the home. Sometimes worse on the shaded sides. Some of the black specks (or spots) can be wiped off by hand while others can not. The stain is of course faded more on the west and southern sides of the home, but seems to have no bearing on the amount of spots.
After taking a trim board down on a particular house and having it analyzed, it was determined that the spots were Black Mold! Returning to the house armed with chlorine, we begin to wipe off the mold using a chlorine and water solution. It came off great!...Until we got to areas where the stain was more intact like shaded areas, under eaves and other less worn areas. The chlorine did not remove it. Under closer examination, we determined that the mold was under the stain. Yes, under the stain!
Remember, we were seeing this on many different houses and are still seeing it today.
Well, One day we were working on a house stripping the old sealer off and next door was a newly constructed log home that had recently been "dried in." We don't do much new construction and I wanted to inspect it closer. I walked over to have a look at the house. It was laid out nice, wrap around porch, two story decks on the back, cathedral ceilings, it was nice.
As I approached the front, it was unfinished (had no sealer on it). I could see the typical strap marks on the logs, footprints where people had walked on them while still on the ground, and these black spots! That is not unusual on bare wood especially if the contractor has taken a long time to finish the job due to weather or other issues that do happen. Well, not too alarmed, because usually at this point the mold and mildew is cleaned from the logs and allowed to dry before sealing, (or at least that is what we do). So as I walk around the house, what do I find? This guy with an airless sprayer just having a ball! Stain flying everywhere! He was getting the job done! (Or use your own phrase). I could not believe what I was seeing. The wall that was getting sealed was just like the front wall, footprints, strap marks and yes mold!
I stopped him to ask if he thought it was alright to stain over an un-prepped surface. His answer did not really surprise me. He told me, in a rather unfriendly tone, "Unless someone is around to stop me, it gets sprayed." I did not know him and there was no signage on his truck. The builder was gone and no way to contact him. We had a short conversation, and I walked away.
I hope this is not the normal practice when finishing log homes, but it does help explain what I have been seeing on my jobs. Mold under stain can be caused by many legitimate reasons. Wood stored in damp locations prior to construction can cause major mold and mildew problems. Moisture content of the logs above 18% when sealed is another factor. These issues are supposed to be addressed prior to sealing (usually) by pressure cleaning the home using a chlorine/TSP solution. The chlorine not only removes mold and mildew, but also kills the spores deep into the wood. TSP is used for removing dirt, clay and other pollutants from the surface leaving the pores of the wood open and ready to receive the sealer.
However, from my experience and coming to my own conclusions, it seems likely that some newly constructed homes are never properly cleaned prior to sealing. Two things are happening. The mildew although maybe not seen at the time of stain application is growing and at some point shows up through the existing stain and keeps growing. Also, the stain is failing prematurely because of not only the mold between it and the wood surface, but also the stain never adhered properly to the wood because of the mold as well as the moisture content of the wood itself. If the wood had been dry (at least at 15% moisture content) the mold would not have appeared to begin with.
Now the problem becomes how to remedy the issue. No easy way out now. The original stain must be removed either by chemical stripping if it is an oil stain or cob blasting if it is a latex. A chlorine solution is then applied to kill any remaining mold or mildew. Oxalic Acid is then used to neutralize the chlorine and stripper in the wood then the wood is allowed to dry completely to a moisture content of at least 15% or lower. The only way to know the moisture content is to use a moisture meter to probe the wood. Anything else is just a guess. At this point the new stain/sealer can be applied and should be applied within at least a two week timeframe. Any later than this and you risk running into more mold and mildew problems.
If your home has black spots or specks on the wood and a chlorine solution will not remove it, there is a good chance you have mold or mildew under the stain. It could be a couple of other things, but that is another story. The best advice is to call a professional and they can determine whether there is mold or mildew or some other problem causing your stain to not look it's best. Log home restoration is more than washing the logs and spraying a fast coat of stain on the wood. For the new log home owner, it is best to do your home work before jumping in what might be a costly adventure.
Earl D. Johnson is the owner of Taskmasters Wood Maintenance. Living in a log home that my wife and I renovated and built two addition rooms allowed us to deal with every aspect of log home maintenance. Our business is log and cedar home, deck and dock restoration. We enjoy sharing our knowledge to help educate the homeowner on proper maintenance techniques so they will have the ability to make informed decisions when planning for their home maintenance and restoration. Be sure to visit our website @ http://www.taskmasters3.com