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How to Clean Mold & Fungi Off the Outside of a Log Cabin

Marlene Affeld

Log homes are functional, durable, warm and inviting. For centuries woodworkers have favored log construction as the material was readily available, natural and fairly easy to work with. Log homes can be found around the world, from humid tropical climates to arid deserts. Log homes are subject to the ravages of wind, rain and cold weather. A moisture buildup in the logs can cause mold and mildew. Following a few simple steps, you can remove mold and fungi from you home and restore it to its original beauty.

  1. Use a stiff broom or brush to remove dust, pollen and surface soil. Carefully inspect the logs and locate areas where mold or fungi is visible.

  2. Mix a solution of 1 part household bleach with 4 parts water and 1/2 cup biodegradable dishwasher soap. Scrub the logs with the solution and a stiff brush. Apply generously. Scrub from the bottom of the foundation and work up to the top.

  3. Rinse with water from the top of the logs down. Use a garden hose with a pressure nozzle, or a power washer, to rinse the logs.

  4. If the logs are severely stained, you can treat them with a commercial preparation of oxalic acid concentrate, available from hardware stores or building supply centers. (Oxalic acid costs about $100 for a five-gallon container.) Apply following manufacturer's label directions. Allow logs to air dry.

  5. Wash painted surfaces with a mixture of 1/2 cup baking soda, 1 cup vinegar and 1 gallon water. Use a sponge or rag to apply, then scrub lightly and rinse with water. This mixture is effective around window and door trim, porches and steps.

  6. Reseal the logs with a penetrating oil-based stain. Do not use a nonpenetrating surface finish such as varnish or polyurethane. Talk to knowledgeable professionals at home supply and building supply stores or log restoration companies. Some sealers have a mold inhibitor already in the stain, and there are additive products that can be mixed with stain to prevent mold. Follow manufacturer's application directions.