Log Home Exterior Inspection Guide
1Frequency of Log Home Exterior Inspection. A thorough cleaning and inspection of the exterior of a log home should be done at least annually. We recommend performing the inspection in the spring so that there will be plenty of time with good weather to do any maintenance that is needed.
2Clean logs and wood surfaces. Remove dirt, dust, pollen, loose wood fibers, and insects, as well as mold, mildew, and algae, which are not always visible, using a log home chemical cleaner such as CPR, Log Wash, or Wood ReNew. Apply the cleaner from the bottom of the wall to the top in order to minimize any streaking. Thoroughly remove the cleaner by rinsing the logs from top to bottom using a pressure washer at a low pressure setting. Since pressure washers can remove stain and damage logs if the water pressure is too high, test a small area if the pressure seems high. If the water pressure cannot be adjusted low enough, you can move away from the logs to lessen the pressure of the water hitting the logs.
3Inspect the condition of stain.
A. MOST IMPORTANT DECISION OF THE INSPECTION: Deciding whether to apply a maintenance coat of stain and/or clear topcoat. A maintenance coat must be applied while the existing stain is in good condition. On one hand, applying a maintenance coat too soon can make the stain too thick and hurt stain breathability. However, after the existing stain fails, it is too late for a maintenance coat, because stain or clear coat applied over failed stain will not adhere to the logs. Where stain has failed, the owner will need to remove the stain and other log products down to bare wood, and then go through the clean, prep, and log product application process to protect the logs.
The Bottom Line: Since the consequences of waiting too long to apply a maintenance coat are so costly, if there is any question about whether the existing stain can last another year, apply a maintenance coat of stain and/or clear topcoat now.
B. Apply a maintenance coat of stain and/or clear topcoat when the existing stain is in good condition, and one or more of the following exist:
1. Water does not bead up well on the existing stain.
2. The stain or clear topcoat has lost its sheen.
3. The stain color has begun to fade.
Stain is OK. Stain has lost its sheen. Needs a maintenance coat.
Stain is OK. Stain has lost its sheen. Needs a maintenance coat.
Stain is OK. Stain has lost its sheen, and begun to fade. Needs a maintenance coat.
Stain is OK. Stain has lost its sheen, and begun to fade. Needs a maintenance coat.
C. When any of the following exist, the stain has failed, and it is too late to apply a maintenance coat:
1. Stain is cracking, flaking, or peeling, or
2. Stain has lost its adhesion to the point that the stain can be removed with a fingernail.
Stain has failed due to peeling.
Stain has failed due to peeling.
While the stain on these logs looks like it may have just lost its sheen, the scratch test shows that the stain has failed since the stain has lost adhesion to the logs.
D. While not all log home stain systems use a clear topcoat, a clear topcoat is applied over most premium log home stains. Since exterior log surfaces need the UV protection of the pigments in stains, a clear coat should never be applied to exterior log surfaces unless it is used as a topcoat over stain. If your stain system includes a clear topcoat, when a maintenance coat is needed, there are two options: (1) if the stain color has not faded, apply only a clear topcoat, or (2) if the stain color has faded, apply a stain coat as well as a clear topcoat. However, if your stain does not use a clear topcoat, when a maintenance coat is needed, apply another coat of stain.
E. It is important to remember that all sides of a log home may not need a maintenance coat of stain and/or clear topcoat at the same time. Since south and west sides of a home typically have more UV exposure, it is likely that those sides of a log home will require a maintenance coat of stain and/or clear topcoat more often than the other sides of the home. You should only apply a maintenance coat when and where it is needed. Besides the cost of the maintenance coat, applying a maintenance coat before it is needed can impair the breathability of the stain.
4Inspect logs. After logs are clean and dry, walk slowly around your home, carefully inspecting the logs and looking for evidence of rot and checks (i.e. cracks) in the logs. Pay extra attention to logs that are more exposed to weather, such as log ends, ends of ridge beams and purlins that extend to the edge of eaves, uncovered portions of logs that extend beyond eaves, bases of log or wood posts, and walls that face prevailing winds. Also inspect logs on the lower courses—especially logs that are adjacent to a deck or walkway, since back splash from rain or runoff water hitting a deck or walkway can keep nearby, lower logs wet, and lead to fungus growth and log decay. If you find evidence of rot, do not panic. The log can be repaired or replaced. But do not put off the repair or replacement. Rot will spread.
A. Logs, Log Ends, and Bases of Log and Wood Posts:
1. To check for rot, do any logs or log ends have any dark, discolored areas, and even, in some cases, have mushrooms growing on those dark areas of the log? If so:
(a) Tap the area with a small hammer to listen for a hollow sound.
(b) Press the area with a sharp tool, looking for softness.
(c) A hollow sound or softness means that decay has probably begun.
(d) If the area of rot is small: After removing the rot, consider installing one or more borate rods, and repairing with wood epoxy products.
(e) For a larger area of rot: Log and/or log end replacement will be needed.
Dark spots on logs indicate decay. Stain is too thick, not allowing logs to breathe.
Darkening exterior of logs indicate that logs have begun to decay. The cut into these logs shows the extent of the decay.
Darker color of the bottom log indicates that it has decay.
Bottom log on the right is rotten, and the two lowest corner log ends are rotting.
Log end rot.
Log end rot.
2. If log ends do not have evidence of rot, but water does not bead up, apply a maintenance coat of stain and/or clear topcoat and an end grain sealer to the log ends.
3. If the base of any log or wood post has signs of rot, (a) the entire post may be replaced, or (b) if the rot is confined to a small area at the base of the post, it is possible to (1) only remove the portion of the base end of the post with rot, (2) mount the remaining post base on a screw jack, and (3) wrap the base of the post and the screw jack with a decorative metal covering, such as copper. Bases of exterior log and wood posts should never be in direct contact with the ground or a solid surface such as concrete, rock, wood, etc., because doing so will expose the base of these posts to constant moisture, leading to fungus growth and rot. Water contacting log ends is much worse than on the sides of logs, because the end grains of logs naturally absorb much more water than other log surfaces. Exterior log and wood posts should always be mounted above the ground or solid surface, preferably on a screw jack, which has the additional benefit of being adjustable to compensate for any log settling.
Rot in the base of a log post.
Extent of the rot in the base of this log post is confirmed by cutting into the post.
Rot in the base of a log post.
Note that even though there were minimal exterior signs of rot in the base of this post, the rot was so extensive that the post had lost its structural stability.
Replacement log post is mounted on a screw jack to keep the base raised above the porch surface to protect it from water.
Replacement log post is mounted on a screw jack hidden by a decorative copper cover, providing easy access to the screw jack.
B. Log Checks. If there are checks (i.e. cracks) in exterior log surfaces that are at least 1/4 inch wide:
1. Clean the check cavity using a log home chemical cleaner to remove dirt, dust, pollen, loose wood fibers, and insects, as well as mold, mildew, and algae, which are not always visible. For best results, using a medium-bristle brush, brush any dirt, loose material or other contaminants from wood surfaces.
Log checks need to be cleaned and caulked.
Log checks need to be cleaned and caulked.
2. Thoroughly remove the cleaner with water using a water hose or a pressure washer at a low pressure setting, and let it dry,
3. Coat the inside of the check with a borate-based preservative to protect the log from any rot that may be inside the check, and let it dry,
4. If the wood in the check appears weak or soft, consider solidifying it with liquid epoxy,
5. If there is room in the check, put backer material in the check cavity, leaving a depth of 3/8 inch to 1/2 inch for caulk, and
6. Seal the check with premium log caulk in the color that best matches the stain on the logs.
5Inspect the condition of chinking and caulking.
A. Are there any cracks in the chinking or caulking? If so, the probable causes are:
1. The logs have moved farther apart than the chink or caulk could stretch,
2. Backer was not used, which limits the stretching capability of chink and caulk,
3. The thickness of the chink or caulk was either too thin or too thick, and/or
4. The age of and/or cumulative UV damage to the chink or caulk.
Caulk in the check in the lower log is cracking. The existing caulk in that check needs to be removed, and all of the checks need to be cleaned and caulked.
Chinking has cracked. Need to remove the old cracked chinking, clean the joint, and apply new chinking.
Chinking has cracked. Need to remove the old cracked chinking, clean the joint, and apply new chinking.
B. Has the chink or caulk separated from either side of the log joint? If so, it was probably caused by the surfaces on the sides of the joint not being properly cleaned and prepped prior to application of the chink or caulk.
Chinking has separated from the log due to improperly cleaning the logs prior to chinking. Need to remove existing chinking, properly clean the log joint, and apply new chinking.
Chinking has separated from the log due to improperly cleaning the logs prior to chinking. Need to remove existing chinking, properly clean the log joint, and apply new chinking.
Caulk is separating from logs. Need to remove the old caulk, properly clean the log joint, and apply new caulk.
C. Are there bubbles in the chinking? Sometimes called blisters, these bubbles can be caused by applying chinking in direct sunlight, which can cause moisture under the chink to expand. Blisters in chinking can also be caused by puncturing closed cell backer rod during installation that can cause a gas to be released (called outgassing).
Blisters in chinking.
D. Solutions to conditions in 5A, 5B, and 5C above:
1. When chink or caulk has cracked or separated from one or both sides of the log joint:
(a) Remove the damaged sections of chinking or caulk,
(b) Clean the joint using a log home chemical cleaner to remove dirt, dust, pollen, loose wood fibers, and insects, as well as mold, mildew and algae. For best results, using a medium-bristle brush, brush any dirt, loose material or other contaminants from wood surfaces.
(c) Thoroughly remove the cleaner with water using a water hose or a pressure washer at a low pressure setting, and let it dry,
(d) Apply a borate-based preservative to both sides of the joint to protect the logs from rot, and let it dry,
(e) Install backer material in the joint, leaving a depth of 3/8 inch to 1/2 inch for chinking or caulk, and
(f) Seal the joint with premium log chinking or caulk.
2. When there are bubbles in the chinking, puncture the bubbles, and gently push the chinking together. After a few days, apply a small additional amount of chinking to smooth out the area.
E. Why use backer material?
1. Backer material serves as a bond breaker, providing a surface to which the chink or caulk will not adhere. The use of backer material on the backside of the joint ensures that the chink or caulk adheres only to the log or other surface on each side of the joint, which allows the chink or caulk to stretch to its full capability with the movement of the logs.
2. Backer material also allows you to adjust the thickness of the chink or caulk, which is important because chink or caulk can crack if it is too thin or too thick. We recommend a sealant thickness of approximately 3/8 inch, but no less than 1/4 inch or more than 1/2 inch. If the depth of the joint is too shallow for backer rod, water resistant tape can be used as a bond breaker. Even if a joint is too shallow for backer material, we recommend caulking it
6Verify that logs are protected from water and moisture.
A. Make sure that water from sprinklers cannot reach the logs, even on windy days.
B. Make sure that gutters and downspouts are clear and functioning properly without leaks.
C. Remove or trim any bushes or shrubs that are within 36 inches of any logs. Plants hold moisture, which can increase moisture on nearby logs. Plants near a log home can also hinder air circulation, which is needed to help keep logs dry.
D. Adjust the grade of the ground around your log home, if needed, to ensure that water flows away from your home.
E. Remove anything else near the home that could cause water to pool near the foundation or splash toward the logs. The goal is to redirect any rainfall or water away from the logs.
7Look for signs of mold and mildew (or algae) on logs. Mold and mildew are fungi that can grow in moist environments with low light levels. They can grow on many types of surfaces, including wood. Since mold and mildew refer to the same living organisms, we will refer to them both as mold. Molds are usually white or black in color, but can be just about any color. If you see discolored areas on your logs, it may be mold. However, if the discolored area is green, it is probably algae. Surface mold and algae are fairly easy to remove with several cleaning products. Chlorine bleach and water solutions have been commonly used in the past to kill and remove surface mold. While it is effective at killing mold, chlorine bleach has the potential to damage wood fibers as well as surrounding plants. Furthermore, chlorine gas, which can be hazardous or fatal, can be released if chlorine bleach is mixed with other household chemicals, such as ammonia. Other more environmentally-friendly cleaning products have been developed that remove mold from wood surfaces. One popular type of these environmentally-friendly cleaners contains oxygen bleach (sodium percarbonate). Regardless of the cleaner that is used, since chemicals from the cleaners can prevent stains from adhering to logs, it is imperative that the logs be rinsed very thoroughly after cleaning to make sure that the cleaner is completely removed from the logs.
Dark areas on these logs are signs of mold. Stain appears to be OK. Need to clean mold off of logs, and determine if a maintenance coat of stain or clear coat is needed.
Signs of mold on logs. Stain has failed and is deteriorating.
8Look for signs of infestation or damage from insects or pests.
A. Carpenter Bees: Round holes in logs about 1/2 inch in diameter.
B. Smaller insect holes in logs.
C. Termite damage and/or termite mud tubes (from the ground up to the wood structure).
D. Signs of gnawing on logs.
E. Signs of birds pecking on logs.
F. Bird, wasp or dirt dauber nests.
For solutions to insect problems, call Log Home Resource Center at 800-441-1564.