Deck Mold Removal

A deck can be a wonderful addition to your home but only if it remains strong and mold-free. Mold is one of the biggest enemies of a deck. With moisture being present outdoors, the mold is bound to find its way onto and into your deck. Typically, mold will begin to appear on the more shaded sides of a deck. Anywhere there is less sun means there is more moisture, making conditions ideal for mold growth.

Once mold infiltrates a surface it only continues to spread if conditions are favorable. Mold can get under wood stains and sealers, causing them to weaken or fail prematurely. Mold will also rot and decay wood if it is neglected, which will jeopardize the integrity of the deck and decrease its longevity.

To remove mold from a deck, clean the surface with a deck cleaner containing tri-sodium phosphate or a mix of commercial bleach and water. We are not fans of bleach on wood; however, sometimes this is the best remedy to get prepped for the finish. If you use bleach, mix at a ratio of one part bleach to five parts water.  Use a pressure washer to clean away the mold, dirt, grime, and blackening. After cleaning a wood deck, the surface should be re-coated with a protective deck stain. Composite decks like Trex should also be protected with the proper sealer.

Black Mold and why it grows in Certain Deck Stains

Exterior deck stains are subjected to the elements, making them prone to natural contaminants. A deck stain is there to shield the wood from harsh weather and the damage it can cause such as rot and decay. In providing protection sometimes the deck stain itself can be compromised.

Black mold is one of the natural occurrences that can affect a wood stain’s effectiveness and longevity. There are several reasons why black mold can grow on, or in, a deck stain. Here are the most common reasons.

Inexpensive or Cheap Deck Stain

Going with a cheap deck stain may save you money initially but may cost you more in the long run. Cheaper deck stains consist of a lower-grade linseed oil that lacks the mildewcides that help fight black mold.

In some areas, black mold is almost impossible to avoid. Hot and humid climates, or areas next to water, are always more prone to all sorts of mold, mildew, and algae. In this situation, black mold can grow on top of a deck stain and jeopardize the overall appearance.

Tip: In this case, use a deck stain that fights against these contaminants and increases the frequency of deck maintenance to keep black mold from becoming a problem.

Oil-Based Stains

Oil-based stains contain both natural and synthetic oils. These oils can potentially feed the growth of mold in the stain itself. All stain manufactures add mildewcides and algaecides to help prevent this. Some like TWP, or Deck Scapes, has an EPA registered wood preservative ingredient which serves as a protector.

Water-Based Stains

Water-based stains do not feed the growth of mold like an oil but stain can attract mold once the stain starts to fail.