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

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.

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.

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.

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.

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.

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.