Archive for August, 2015

August 25th, 2015

Cleaning Black Spots From A Cedar Fence

cedar fenceDoes your beautiful cedar fence have discoloration? Never fear. This post will walk you through when and how to clean your fence.

As cedar ages, the wood slowly changes color. Your fence will progress into a grayish (or even silver) shade over time. You cannot simply clean this natural discoloration away.

Black spots or stains, on the other hand, are not the natural progression. Cleaning can remove ugly black marks from your fence.

What causes these black marks?

The most common culprits are tannins, mildew, and mold. Tannins ordinarily leach from cedar wood, and do not normally cause any problems. However, when tannins mix with metal and iron, a chemical reaction occurs and a black stain can form.

Cedar, along with any other wood, is a natural habitat for mildew and mold. The spores can thrive on your fence. Thankfully, cleaning usually removes mildew and mold stains.

First, spot-check the stain. This simple test checks to see if the stain is from mildew and mold, or from tannins. Simply rub a small drop of bleach onto the stain, and wait a few minutes. If the stain lightens, mold is the likely culprit. You can proceed with the cleaning. If it doesn’t lighten, you are likely dealing with tannins. You can

Fill a bucket with a gallon of warm water. Add a little bleach (not too much—it can ruin the wood!).
Using a soft rag, gently wipe the stain. Scrubbing hard can permanently scratch the wood, causing damage. Once you have cleaned all of the black stains, allow the wood to dry in the sun. The stains should be noticeably lighter. You can proceed again until the stains are gone, if necessary.

What happens if your stains did not lighten in your spot test? It means you likely have tannin stains and will need something a little more powerful than bleach to clean your fence.
To clean the tannin stains, you will need a mixture of warm water and a small amount of oxalic acid. Wearing protective goggles and gloves, carefully wipe the tannin stains with a soft cloth dipped into the cleaning mixture. Wipe over the area with a dry cloth, and allow to air dry.

If you are in the Boise area, and unable to clean your fence, or would prefer to stain it to rejuvenate the whole thing at once, consider contacting a fencing contractor in Boise like Boulder Creek Fence. Cedar fencing professionals can help you restore your cedar fence to near new beauty.