How to Prevent Wood Rot

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In its natural form, the decomposition of wood is a normal process, which converts fallen foliage, branches, and logs into nutrition for the soil. We call this occurrence wood rot, and once rotted, wood becomes unusable. When wood rot occurs in processed wood as in furniture and homes, it creates a problem.

Wood rot can lead to a variety of structural problems like deterioration of posts, beams, joists, and wood flooring. When wood rots you have to replace it, which can prove to be a costly project often running into tens of thousands of dollars. Wood rot is often difficult to detect because it begins in concealed or restricted spaces.

In this post, we take a look at some of the primary causes of wood rot and the different types that commonly occur. Then, we move on to the precautionary steps that you can take to prevent wood rot from occurring in the first place. So, let’s jump right in!

Why Does Wood Rot Occur?

Small wooden cabin

Wood rot occurs when moisture and fungus combine to attack wood to make it powdery and weak. Fungi needs continuous moisture to survive and it does not grow on dry wood. There are as many as five million types of fungi in the air. Many varieties of fungi like yeast and mushrooms are beneficial to us, whereas others are destructive. Wood rot falls under different categories according to the varied effects they have on wood.

Types of Wood Rot

Fungi affect the wood in different ways and we name each type of rot according to the way each fungus affects wood. Here are the three types of wood rot:

Brown Rot

nice abstract patterns left by termites

We also call this type of rot “dry rot” because it makes the surface of the wood dry-looking. Dry rot affects the cellulose structure of the wood, giving it a deep brown color. The result is that the wood breaks into cube-shaped bits and we call this process “cubical fracture.”

Brown rot needs a temperature of 65°F to 90°F to survive. Once brown rot starts to grow, it spreads rapidly.

White Rot

Close up of rotten sash window frame




With white rot, the wood becomes whitish or yellowish and acquires a spongy texture. With white rot, the fungus attacks the lignin content of the wood. White rot also needs temperatures in the range of 65°F and 90°F to survive.

Soft Rot

lying birch tree in a forest

The decomposition process of soft rot is slower than that of white or brown rot. It has a higher temperature tolerance than the fungi in the other types of rot. Soft rot thrives in temperatures ranging from 0°F to 110°F. The fungi that cause soft rot cause the cellulose of the wood to break down and creates a honeycomb-like structure on the residual wood.

Where is Wood Rot Most Likely to Occur?

Wood rot appears in persistently damp areas and most of these areas are in concealed locations. Due to this reason, it can go undetected for a long time, until perhaps exposed during a remodeling project. Here are some of the primary areas where you can expect to find wood rot:


Rotten old wooden window

Modern windows have waterproof designs, but even a small gap in the caulking can allow rainwater to seep in and soak the wood within. If portions of the wood are concealed, that area will continue to be damp, promoting fungal growth. Older wood is more at risk because of the presence of cracks in the wood and paint where water can accumulate.

Exterior Doors

Grungy details of ruined building in European city Odesa Ukraine

Just like with windows, a door can have cracks and gaps between the siding and the door where water may enter and accumulate. Because this is a concealed spot in the door, homeowners may miss it and only notice it when it is time to replace the door. On removing the door frame, they will see the wood rot. At that stage, the only remedy will be to replace not only the door but also the frame, thereby shooting up the cost of the project.

Outdoor Decks

Stock photo of deck of residential house

Wood that we use outdoors usually has some form or the other of water-resistant treatment. However, the wood is never completely waterproof, and especially in outdoor decks, on the bottom of painted balusters and posts, water can accumulate at the joints exposing the wood to the risk of rot.


Water damaged ceiling and wall

The high humidity and moisture content of a basement is the perfect setting for the proliferation of fungi and thereby wood rot. Although a basement is made of concrete, the walls are surrounded on the outside by soil which can make the inside so humid that water vapor can accumulate on the inner surfaces.

This explains why a basement smells musty and that mustiness is due to the accumulation of fungi. Since the basement is a place seldom frequented, and also dark and secluded, wood rot can develop for a long time before being detected.

Wet Rooms

abandoned school hall in Pripyat

Any room like a kitchen, bathroom, or laundry room that has plumbing and is exposed to water regularly can develop wood rot in the wooden fixtures. You are most likely to see wood rot develop in locations of leaky plumbing around the woodwork.

Damaged Roofing

Man Collecting Water In basin From Ceiling

If shingles are missing or damaged, there can be leakages that will allow water seepage, and wood rot can occur in the decking of the roof, rafters, and wooden beams in the attic.

How to Prevent Wood Rot

KEMEROVO, RUSSIA, DECEMBER 10, 2018. Piles of planks and timbers

Now that you are aware of the different types of rot, where it is likely to occur, and why it occurs in the first place. Let’s have a brief look at the basic steps that we can take to prevent wood rot:

  • Use pressure-treated lumber wherever possible, especially if the wood is going to be in direct contact with the ground.
  • If your project involves wood that is going to be outdoors, use paint or sealant on the outer surface of the wood.
  • Avoid leaning objects like tools, old wooden structures, and ladders on your siding.
  • Ensure to clean all the gutters periodically to avoid stagnation of water.
  • Try to limit the direct exposure of wood to the ground, to limit moisture accumulation from the soil.
  • Maintain a slope on horizontal sections of wood to prevent the accumulation of rainwater.
  • Prevent plants and creepers from growing across the wood, as this will also increase the moisture content.
  • Apply anti-fungal chemicals to any wood that is likely to be outdoors or exposed to moisture.

A common question we get is if bleach prevents wood rot?


Wood rot is something that can occur to even the best and most superior types of wood. Prevention, as we all know, is better than cure. In fact, in this case, there is no cure. Wood that has been affected with rot needs to be discarded. To prevent wood rot from occurring, the best way is to keep the wood dry. If you keep your wood dry, it will never deteriorate due to wood rot.

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