Before you apply any stain or finish to your logs, check all wood surfaces for deterioration, decay, dirt, mold and mildew. You can usually distinguish mold and mildew from dirt spots by touching the suspect spot with a cotton swab soaked with chlorine bleach. If the bleach clears the spot, then it is mold rather than dirt.

Repair decayed wood using appropriate restoration techniques. If you detect signs of excessive moisture (darkened wood, excessive mold and mildew) remove moisture sources and treat the wood with borates to prevent wood rot.

Remember that consistent preparation is important because your finishes highlight wood grain and texture, and seal in any blemishes left during the preparation process.
Periodic cleaning of your exterior walls is important to appearance and to help prevent growth of mold and algae on the walls. When you clean your exterior walls, always be careful to do it in ways that cause the least harm to your finishes.

  • Always use mild solution of cleaners on the wall.
  • Strong cleaners may damage your finish! If in doubt, try your solution in an inconspicuous area before proceeding.
  • Always use a mist setting on water nozzles, not a forceful jet.
  • Always use soft bristled brushes or non-abrasive pads for cleaning.
  1. Mill Glaze

    On new wood, remove mill glaze by allowing wood to weather for 90 days, by sanding, by power washing or by using Log Wash or Wood ReNew from Perma-Chink Systems, Inc.
  2. Clear Finishes

    Always avoid clear finishes which don't block the damaging ultraviolet rays of the sun. Even clear finishes that advertise UV blockage will not perform as well as pigmented finishes. UV light breaks down the lignin, a complex chemical that makes up about 25 percent of a log's substance and acts as the "glue" that holds wood fiber together.

    If you like the gray look of weathered wood, you can approximate it without sacrificing your logs by using finishes that contain gray pigments. You can use clear finishes on the interior logs.

    Remember, exterior walls weather unevenly, depending on exposure to sunlight and water. All things being equal, the North and East sides of the house require the least maintenance. Regularly inspect exposed log ends.

    Regular inspection of your exterior finishes will help ensure the beauty and protection of your precious logs. In addition, regular maintenance results in the lowest cost of maintaining your finish because it delays the requirement to completely remove old deteriorated finishes.
  3. Old Finishes

    If you are going to recoat over existing finishes, evaluate the adhesion of the existing finish by applying and peeling masking tape from the surface in a few representative areas. If very little finish is removed with the tape, then the adhesion should be adequate to provide a base for your new stain. If significant amounts of stain remain on peeled tape, then remove the old finish before application of new.

    If you are going to completely remove your old finishes, you have a few options. If the old finish is seriously degraded, strong cleaners may completely remove it. However, in protected areas, removal is usually difficult with this method.

    We suggest that for a complete finish removal you use a chemical finish remover along with a pressure washer.

    Just be sure to thoroughly clean all chemical residues from the wood surfaces to avoid any interaction they may have with your newly applied finishes. Additionally, carefully follow the manufacturers use and safety instructions.
In years past, most log homes were small second summer homes and/or hunting or fishing camps. Today's typical log home is a family's primary residence that involves a substantial investment of at least one hundred thousand dollars. With this in mind it is no wonder that log home owners are concerned about protecting their homes against wood destroying organisms.

Prior to the 1930's, most log homes were constructed from large logs from which the sapwood was removed leaving dense, insect resistant heartwood.

Most log homes are now made from fast grown pine, spruce, or fir consisting mostly of sapwood. Some are constructed of more insect resistant wood species such as cedar, cypress or hemlock. However, even these woods lose their resistance over time and become prone to infestations.

One major pest control company estimated that 40% of the log homes they inspected had some type of active insect or decay infestation. Approximately 14,000 log homes are constructed each year. This includes homes made from both milled and hand peeled logs. Some homes are supplied as kits while others are constructed by the manufacturer. In addition to log homes, timber frame (also known as post and beam) structures are becoming popular. They too suffer from a high risk of beetle and decay infestations.

Typically, a pest control company is contacted by an owner to solve an existing problem. Although it would be easier and less expensive to do a preventative treatment to a log home during the construction process, it rarely occurs. Many log home suppliers are reluctant to admit that their product is subject to insect and decay infestations. Some of the more responsible manufacturers have taken it upon themselves to pretreat their logs with borates, thus preventing many of the problems associated with log homes.
Treating Log Homes

Spot Treatments

Spot treatments are rarely effective in controlling infestations of wood boring beetles in log homes. Since emergence holes are created at the end of a beetle's life cycle, larvae may be active in many areas of the home with no visible signs of an infestation. Isolated Old House Borers can sometimes be located and eliminated using one of the wood injection systems.

If the larva has already made its emergence hole, it can be used to access that particular beetle larva. Frequently an Old House Borer larva has reached a stage where it is large enough to be heard but has not yet made its' emergence hole. In order for a spot treatment to be effective, larvae must be located within a couple of inches.

The best way of locating an individual larva is by using a stethoscope and marking the loudest spot with chalk. This process works best at night when beetle larvae are most active.

Pockets of decayed wood can be treated using one of the borates. The treatment will not restore the integrity of the wood nor should it be used in place of correcting any moisture problem. Decayed areas should also be excavated and filled in with appropriate materials in order to prevent further water infiltration.

Borate Treatments

The first step before treating any log home with a borate is make sure there is no water repellent finish on the wood. Some water repellent finishes are clear and colorless, so there is no way to determine if a water repellent is present by just looking at it. The best way to determine the presence of a water repellent is to spray the wood with water. A quart plant mister works well. If the water beads up or does not soak into the wood within a minute or so, there is something present which will inhibit the penetration of the borate. When checking for the presence of a water repellent pay particular attention to areas under roofs, eaves, and other sections of the home protected from the sun and weather. Water repellents last much longer in these protected areas. If an intact water repellent is present, it must be removed by pressure washing or other means before treatment. If interior logs surfaces are going to be treated, it is important to check them too, even if you are positive that they have never been coated or treated. If the home has been lived in for a year or more, interior logs will acquire a coating of cooking oil, especially around kitchen and dining areas. This oil residue must be removed with a strong detergent prior to treatment.

Why is it so important to remove any water repellent before treatment? First, the borate must be allowed to penetrate into the wood to get where insect larvae are feeding in order to do any good. Second, if the borate does not penetrate and dries and crystallizes on the surface, it will create white deposits that may be difficult to remove. These deposits can usually be cleaned up with warm water. But if a stain or finish has been applied over them, they are almost impossible to remove without stripping. Most log home owners are particularly demanding about the appearance of their home and do not appreciate white logs. The number one cause of complaint regarding borate treatments to log homes is not efficacy but cosmetic damage.

Once log surfaces are cleaned and dry, a borate may be applied according to the manufacturer's recommendations. Some people, upon learning that borates penetrate damp wood faster than dry wood, have attempted to aid penetration by wetting the logs with water just prior to applying the borate. This will not work since once a log is dry just wetting the surface does little to raise the moisture content of the interior wood. In addition, wetting the logs fills the surface of the wood with water, allowing less borate solution to adhere to the wood. This decreases the amount of active ingredient being applied to the logs. After the borate treatment is completed and the logs are dry, stain or water repellent should be applied to exterior surfaces. This is where many pest control operators get themselves into trouble.

Results & Expectations

Borate treatments can be quite effective in preventing and eliminating most wood destroying organism infestations. However, the last stages of Old House Borer larvae are resistant to low levels of borate and can survive for several months after a borate treatment. Emergence of Old House Borers has been reported as long as a year and a half after treatment. Younger beetle larvae will be eliminated and eventually the infestation will end.
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