How to Deal with Mold on Your New Deck?

The deck, that wonderful space in your home where you can do so much more than just relax, is truly a versatile feature. Whether you’re gathering with friends, enjoying some peaceful downtime, or hosting a delightful outdoor event, the deck is where it all happens. And let’s not forget about its aesthetic appeal—it adds a touch of charm to your outdoor space, depending on the material it’s made from. But there’s more to it than meets the eye; the deck’s durability is a crucial factor to consider.

Once upon a time, lumber was the go-to choice for deck construction. However, as time went on, its limitations became apparent, and we had to bid farewell to this once-beloved material. Enter the new kid on the block: composite products. These modern marvels have revolutionized deck building by combining the best properties of different materials while mitigating their drawbacks. That’s why composite decking offers many advantages over their lumber counterparts, thanks to their remarkable resistance to the elements that can wreak havoc on traditional decks.

Since decks reside outdoors, they face the brunt of Mother Nature’s whims, especially in areas prone to heavy rainfall or high humidity. These environmental conditions create the perfect breeding ground for mold to thrive. Unfortunately, even the sturdiest decks in these regions are not spared from this uninvited guest, and outdoor features, in particular, fall victim to its unsightly presence. The appearance of mold can tarnish the beauty of your deck, regardless of whether it’s made from composite materials or not, as mold doesn’t discriminate.

Dealing with Molds on Your Decks: What Causes Mold Growth on Decks?

Living in an area with high rainfall and humidity can take a toll on your outdoor deck. It becomes a battleground for the elements, facing harsh weather conditions head-on. And let’s tell you, when it comes to your deck, those conditions can lead to an unwanted guest: mold.

Imagine mold sneaking in from unexpected places, quietly making itself at home before spreading to more noticeable areas. It’s like a stealthy invader, taking advantage of the dampness of exposure to the elements. You see, decks exposed to damp weather provide the perfect breeding ground for mold to thrive. 

So, when you spot those unsightly mold patches on your deck, it’s a clear sign that moisture is lurking somewhere, creating an environment that supports their growth. It’s like nature’s way of saying, “Hey, there’s a moisture party going on here!”

Understanding the connection between moisture and mold is the first step toward reclaiming your deck. By identifying the source of moisture and addressing it, you can prevent those pesky mold colonies from taking over.

Dealing with Molds on Your Decks:  What Kind of Decks Are Affected by Molds?

Let’s face it: mold can grow almost anywhere if the conditions are right. But here’s the kicker—different surfaces have different levels of vulnerability regarding mold growth. Take timber decks, for example. They practically roll out the red carpet for mold. These little troublemakers can infiltrate the very heart of the timber, causing it to rot and decay, especially in lumber decks. It’s like they’re throwing a party and inviting all their moldy friends!

Now, let’s talk about composite decks. Mold doesn’t have quite the same effect on them. Sure, mold can still make an appearance, but it’s a much slower and less menacing process. Moisture doesn’t pose as much of a threat to composite decks unless you have some seriously damp and humid weather going on. 

Before moisture can even think about sneaking into the core of a composite deck, those pesky mold spores start forming on the surface. But don’t worry! With a good cleaning and some regular deck maintenance, you can easily take care of this mold issue. Mold takes its sweet time to cause serious damage to composite decks, so you’ve got some breathing room.

But how can you address molds when you notice them on your decks?

Checking for Molds on Your Decks and Where to Check

Before you can with molds on your decks, you must know where to look and what you are looking for. Hence, what are the types of molds particular to surfaces?

Two types of molds are particular to surfaces, and their color identifies them. They are:

  • Black mold: This mold is not black, but it features a dark-greenish tone or a mixture of other colors, and it is the most common mold type found on surfaces. These molds can also pose severe health threats if left unattended.
  • White mold: Unfortunately, this is less popular than black mold. This mold thrives on wood and moisture; a whitish color does not characterize it. Instead, you notice discoloration on the affected surface or white-like spots.

After knowing what molds look like, it is clear that inspection is the only way to identify molds on your decks and take preventive measures against them. Where should you then check for these molds after knowing how to identify them? Some of the places to check include:

  • Look beyond the top surface, as it only creeps to the top surface when it has matured into a serious concern. Hence, it would help if you remembered to look under your deck so you are not caught off guard when it appears on the surface.

Ridding Your Deck of Molds

There are techniques or measures used to rid your deck of molds, and what are these techniques? They are:

  1. Pressure washer: This might seem like a direct technique, but it is not because when you use the obvious application, you might cause damage to your deck. These are tips to guide using a pressure washer;
  • When using a pressure washer, use a fan tip end on the pressure washer because you need an even flow generated from the hose. This even flow also allows for even pressure distribution, so the pressure is not concentrated on one area on the deck’s surface.
  • When using a pressure washer, let your aim be precise on the surface you are cleaning.
  • If you notice you have not gotten the hang of the pressure washer, it is best to be safe and hire the services of a professional cleaner.

You should note that the process and tips outlined above must be repeated several times before returning your deck’s surface to its original state.

  1. Eco-friendly options: The above technique can sometimes be dangerous to the ecosystem if misapplied. This is why eco-friendly techniques are considered safer and better, although they can be tedious. Some of the eco-friendly and natural techniques include:
  • Using tea tree oil: Mix two teaspoons of tea tree oil into a bottle containing two cups of water and mix vigorously.
  • Fermented vinegar: Vinegar is perfect for cleaning molds, as its chemical composition allows them to remove molds quickly. Once you apply fermented vinegar across the affected surface, leave for about 20 minutes before you clean it with a damp sponge.
  • Use a mixture of clove and baby oil on the cleaned surface after removing the molds on the surface.

In case it was not mentioned earlier, molds are highly resistant (stubborn), so you must repeat the process several times to get the clean surface you desire.

  1. Hiring a professional cleaner: Hiring an experienced cleaner will demand an extra cost. Still, it is better to spend this additional cost on professional cleaners and have your deck looking its best than on deck repairs because it was damaged while ridding the surface of molds yourself.


Dealing with mold on your deck can be done in different ways. You can take corrective measures to stop the mold from causing severe damage, and there are preventive measures to stop the mold from developing. The preventive measures involve addressing the root cause of mold growth and moisture, but it is another topic for another day.

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