Wood Rot Part 3 -Unicoi Ludd

Wood Rot Part 3. 

We've learned that keeping wood dry is the key to preventing decay. We've also learned that barrier methods of preservation, coatings such as paints, varnishes & urethanes are effective at keeping wood dry as long as they are intact and well maintained. We have also learned that these are not practical or effective when wood is in direct contact with the soil, as with fence posts, piles or sills. Now we'll discuss chemical treatments that discourage fungi, microbes & bacteria. This post will deal with the common treatments and the next will deal with more natural methods. We are probably all familiar with the "preassure treated wood" commonly sold in the lumber store. The wood is placed in a pressure vessel and infused with chemicals that make the wood distasteful to our wood destroying enemies. These chemical treatments fall into some general categories like water or oil soluble, borates, LOSP etc. the most common are those that use the anti microbial properties of copper such as ACQ, CAC & CCA. These are the greenish tinged lumber in the big box stores. The treatments are done to various degrees which is why some say "ground contact" and others don't. These chemical treatments have proven very effective over the years and the chemical composition has been changed to reduce the toxicity. You should research the specific product you intend to use to know the level of toxicity & safe handling procedures. Leaching of these chemicals into the soil may be a concern, so I'll let you make your own decisions. Another common preservative are Borates- again the purpose is to make the wood unappetizing to fungi etc. Borates are a generally less toxic treatment, but are water soluble and will slowly leach out of the wood. LOSP stands for Light Organic Solvent Preservative - an example is Kerosene (also used to preserve burlap bags) and the last are oil based, most commonly Creosote. That black, tarry stuff on utility poles with its distinctive smell, it is not generally sold to the public any more. Be aware that if you use old poles or creosote treated wood, you should protect your skin. Creosote causes photosensitivity and just the saw dust from cutting up a pole can give you the worst sunburn you've ever had. All theses treatments work by discouraging fungi etc from eating the wood fibers the same way - toxicity. At this point I'll say a word about what a lot of you are thinking - "what about used motor oil"? Yes, soaking or painting motor oil on wood will discourage fungi & microbes and greatly increase the life of fence posts. Most municipalities, State & Federal policies DO NOT LIKE THIS! So it would be wrong for me to suggest that placing fence posts loosely in a metal barrel, filling with used motor oil and allowing to soak for a couple of months would be an excellent preservation method. Not only would such a procedure render the wood toxic, it also imparts considerable water repellency. But that would be frowned upon by the afore mentioned entities and viewed as an "oil spill" so I won't recommend it. Post # 4 will deal with natural preservation methods.