How to Remove a Stain on Cedar Siding

Cedar siding is known for its durability, its ability to effectively bind with finishes and for having beautiful warm, yellow-red tones.
However, over time cedar siding can succumb to the elements and accumulate stains. Stains on cedar siding are typically caused by moisture-induced mold and mildew. Mold and mildew can cause unsightly black and brown stains and if not properly taken care of, these stains will grow, penetrate deeper into the wood and become more and more difficult to remove. Follow these basic steps for removing and preventing stains on your cedar siding.

Step 1

Spray the area with a garden hose with a sprayer attachment to remove dirt and particles. Do not use a high-pressure washer as this can damage the surface fibers of the wood.

Step 2

Scrub the area with a bleach-free commercial mildew remover or with oxygen bleach. Both of these products will kill mold and mildew and deeply clean the wood. Scrub using a soft, plastic-bristle scrub brush. Do not use a metal scrub brush as this will also damage the surface fibers of the wood.

Step 3

Rinse the area with fresh water.

Step 4

Follow up the mildew-cleaning agent by scrubbing the area with a solution of water and a bleach-free, ammonia-free household detergent such as liquid dish soap.

Step 5

Rinse the area with fresh water and allow the wood to dry.

Step 6

Refinish your cedar siding every two to four years, depending on the moisture levels where you live. Use a finish with synthetic resin, as natural resins have ingredients that are favorable for mold and mildew growth. Refinish your cedar siding directly after cleaning stains if the stain growth was extensive.

Things You Will Need

  • Garden hose
  • Plastic bristle scrub brush
  • Commercial mildew remover or oxygen bleach
  • Household detergent

About the Author

Mason Howard is an artist and writer in Minneapolis. Howard's work has been published in the "Creative Quarterly Journal of Art & Design" and "New American Paintings." He has also written for art exhibition catalogs and publications. Howard's recent writing includes covering popular culture, home improvement, cooking, health and fitness. He received his Master of Fine Arts from the University of Minnesota.