Use a pressure hose to wash down the logs. It is easier to see evidence of log damage if the the logs are clean. When the logs have dried, carefully examine each log. Inspect the foundation, crawl space, attic and under the eves. Tap along each log with a hammer. If the log is rotted internally, the hammer will cause a hollow sound. Poke at the spot with a screwdriver point or ice pick. If the log is easily penetrated, it is rotted. Mark sections of log rot with colored plastic tape. (Log rot is often caused by moisture buildup. Logs along the foundation are most affected. Snow accumulation and rain-splash often cause severe damage.)
Inspect the roof. Look for "swags" or settling where the roof has bowed. Examine the roof joists.
Eliminate termites or other insect infestation evident in the logs. Termites and carpenter ants can cause extensive damage to a log home. Make sure that the infestation is controlled before proceeding with repairs.
Enlist the services of a log-home professional if the log rot is extensive. A complete inspection and consultation will save both money and time. Many of the repairs can be accomplished by the do-it-yourself homeowner, however if the home's structural integrity is compromised, professional equipment and experience are recommended.
Chip out small areas of rot with a hammer and chisel. Remove all rotted material until sound wood is encountered. Apply a coat of petroleum-based shingle oil to coat the wood. Fill in the damaged area with epoxy, following directions on the oil container.
Cut out larger portions of damaged logs with a saber saw equipped with a metal cutting blade. The blade will cut through nails, spikes or posts that may be holding the log in place. Use a pry bar to help remove the cut portion of log. Use a chain saw to cut a new section of log to fit the spot where the log was removed. Choose a log of similar type and style as the section you removed. Use 2-inch wood screws to attach metal plates on both ends of the replacement log, joining the new log to the adjoining log section.
Cover repaired section with shingle oil to preserve the wood and replace the caulking.