How To Prevent Mildew On Unpainted Wood: 3 Essential Tips

Knowing how to prevent mildew on unpainted wood would make you worry less and make mildew problems manageable. If you believe that unpainted woods are more prone to mildew growth than a painted one, then you should read this article.

Amongst all organic matters, wood would likely be at the top that mildew loves to thrive. With that circumstance, some choose to paint their wood, believing that it could prevent the mildew from emerging.

how to prevent mildew on unpainted wood

Wood has long been part of constructing traditional and modern houses, from interior to exterior. Given that wood is a raw material and susceptible to mildew, choosing the best wood for your house is as crucial as picking house design.


What Is Mildew?

To prevent mildew on unpainted wood entirely, it is best to understand first what mildew is. As you know, mildew is one of the variants of fungi closely related to mold.

Mildew is commonly seen as patches of white or gray on any surface with flat growth, unlike mold. Usually, distinguishing mildew from mold is hard, but once you familiarize their difference, it will be easy for you to deal with them.

In the same case with mold, mildew can grow in any area and in changing environmental conditions. Yet, mildew commonly thrives in organic matters, such as food, paper, wood, plants, and other organic materials.

Due to the high humidity, moisture exposure, and presence of bacterial contamination, mildew can grow rapidly through its spores that travel in the air. If you are not bothered with mildew, well, you should understand that mildew spores are a risk to your health, especially when you suffer respiratory problems.

Another thing is that you might find mildew irritating because of its smell. Therefore, you must recognize what does mildew smell like to become guided on possible interventions that you may take.


What Causes Mildew On Unpainted Wood?

As mentioned above, mildew can ideally thrive in different areas and environments. For that reason, it is imperative to know what causes mildew on unpainted wood.


Wood condition

The first thing you might consider is the current condition of your unpainted wood if it is used for either indoor or outdoor. Basically, unpainted wood is prone to mildew since there is no protective material like paint used.

Moreover, mildew would like to thrive on unpainted wood as it gets old. As time goes by, the wood also matures, and it can no longer withstand various environmental conditions, which are perfect for mildew growth.

Lastly, a newly harvested wood is vulnerable to mildew due to its watery condition. Therefore, drying the wood before using it is suggested, mainly if it will be used for indoor matters.


Exposure to moisture

Moisture exposure would be one of the best reasons mildew grows on unpainted wood. If you look closely at the surface structure of wood, you will notice small holes, almost like a sponge.

These holes trap moisture which destroys the wood in the long run. It could also be the perfect breeding ground for mildew, given that moisture, organic material, and oxygen are within.

Usually, unpainted woods outdoors that are used in fences, patio, and outdoor wooden furniture and woods used in attic and basement are most likely to experience mildew infestation.


Things that prevent mildew on unpainted wood


1. Keep it dry

When it comes to preventing mildew growth on unpainted wood, the best thing to do is keep it dry or store it in a dry environment. The chances of mildew would be lessened because it cannot survive in a dry condition.

This would only apply to indoor woods, since unpainted wood outdoors would possibly get wet due to weather conditions. On the other hand, if your woods aren’t used, you have to store them in a dry place or at least cover them dry.


2. Apply protective coat

If you are not supposed to paint your wood, considering a suitable sealant is the best thing to consider. Applying sealant to your wood would not likely prevent mildew, but also protect from other elements.

Additionally, proper sealant helps preserve the wood, while preventing the wood from rotting. 


3. Chemical treatment

Using chemical treatment to prevent mildew on unpainted wood is more convenient than natural remedies. As you know, there are various chemical formulas available in stores that solve the problem of mildew on wood.

There are different wood preservatives that provide protection from weathering and direct contact with mildew spores. Here are some best selling products available online:

  • Barrettine Premier Wood Preserver
  • Ronseal Total Wood Preservative
  • Cuprinol 5 Star Complete Wood Treatment
  • Osmo Wood Protector
  • Sadolin Quick Drying Wood Preserver

Even when you apply such protective coating or wood preservatives, you can still use mildew killer solutions on your wood. Just make sure that you are equipped with safety gear and keep it away from children.



Knowing how to prevent mildew on unpainted wood provides you an edge for home maintenance. While you have to be aware that even painted wood can develop mildew, you might as well learn how to remove mildew from painted wood.

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