Log Home Restoration: Why Clear Sealers Should Not Be Used
I have found through the years what seems to be a common thread among most newly constructed log homes, and log home owners who seek truthful answers concerning their log home restoration.
Most, if not all of the log homes are sealed with a clear sealer or a clear sealer with toner added to give the log home the "natural look." Most are only 1 to 2 years old and are turning black in places. The logs are looking gray as well as a substantial amount of wood discoloration caused from water splash back along the bottom run of logs at or near the decks and at the dormers along the roof line.
Most, if not all of the log home owners like the "natural" look of the logs when first sealed and want to keep that look. Most expected the sealers to last longer than 1 or 2 years, and most if not all are dissatisfied with the overall performance.
After understanding what a "natural" or "clear" sealer is, you may want to reconsider what to put back on your log home or log cabin. If a clear has been applied to your logs, it is not a stain, but rather a sealer. Clear sealers do little more than repel water to some degree. Although it may provide some protection from water, it can actually do more harm than good by sealing water in as well as sealing water out.
Actually, UV rays are far more detrimental to the logs than water. Therefore blocking the sun rays is of greater importance than blocking the water. Blocking sun rays or "UV" rays is accomplished by adding Iron Oxide pigment to the stain or sealer. The pigment not only blocks UV rays, but it also reflects the UV rays as well as adds color to the coating. The more pigment that is added, the darker the color. Therefore, the darker the color, the more protection from UV rays. So if the darker colors provide the most protection, then it stands to reason, the lighter
colors (or clear) provides the least protection.
Everyone loves the "natural" look on their logs. The problem is that the natural look is either a clear sealer or a clear sealer with a toner usually of a honey color to mimic that natural look. Here in-lies the problem; Light toners have very little pigment, therefore very little protection.
So, it is a trade off. The natural look (that everyone loves) with little protection, or a darker color with more protection.
Please be aware that if you use a natural or lighter color, you will have to re-coat every year, and then you may have trouble with mildew and graying wood. It is recommended to use the darkest color but still suit your taste. A "middle of the road" color such as a pecan is a good choice. Still relatively light, it has a substantial amount of pigment to provide reasonable protection from the elements.
Earlier I stated that a clear sealer could do more harm than good. Most (but not all) clear sealers do exactly that, they seal the wood. They do seal water out just like advertised, but they can also seal water, dirt and mildew in. If the wood is not completely dry, (dry being considered at least a 12% moisture content or lower,) the water trapped behind the sealer is going to escape. As this happens, micro cracks are formed on the backside of the sealer and are invisible to the eye. When the logs contract and expand (due to temperature changes) these cracks will surface. When this happens, the logs can then absorb more moisture and attract mildew compounding the problem. The cycle continues until the sealer fails, the logs turn gray and black mildew is present.
Now there are two options; wash the logs with bleach which will kill the mildew, let the wood dry and apply another coat of sealer. Not the best choice considering the sealer to be re coated is already cracking and failing, but oftentimes this method is used as a cheap remedy.
The other option (recommended) is to remove the failing sealer by using a chemical stripping process and then apply a pigmented oil based stain. You not only will have a coating that will not crack or peel, but with a dark pigment, you will get much better performance than with a natural or clear sealer.
Unless the log home owner is willing to do the extra maintenance required to keep that "natural" look, a good quality oil based pigmented stain would be a more particle finish to use during the log home restoration process.
Douglas Johnson
Taskmasters Wood Maintenance
