It’s a part of the natural cycle of life. When trees fall and the wood dies, it needs a way to return to the earth and become soil once more: it rots away. Unfortunately, the same applies to the wood that we use to build our homes when exposed to the right conditions. Wood rot can come in two forms, wet rot and dry rot. While these two forms of wood rot have different ways of growing and spreading, they both have one thing in common: they require moisture.

Today, let’s take a dive into these two kinds of wood rot, how to identify it, and ultimately, what needs to be done to get it fixed!

Types of Wood Rot

Wet Rot

Wet Rot due to humidity and growth of molds wooden roof structures

What Is It?

Wet rot refers to a species of fungus that eats wood, especially wood that is in buildings. The way that wet rot lives and grows is by using the moisture present in the wood and digesting nutrients contained in that wood. After it has consumed enough moisture and nutrients, the wet rot will begin creating and releasing spores into the air, so that those spores can land on other moist wood surfaces to begin the life cycle anew.

There are actually several species of fungus that make up wet rot, but they generally require a moisture content of about 50% for their spores to begin the process of taking root and growing.

Common Causes of Wet Rot

Wet rot often happens in sites where a moisture problem has occurred and remains ongoing. Whether this is an external problem like invasive moisture coming through a foundation crack, or interior like leaks in your plumbing, wet rot will take advantage of it when that moisture begins soaking into nearby wood structures within your home. Here’s a list of examples of how wet rot can get the moisture it needs in your home:

  • Roof problems such as leaks.
  • Leaks in your plumbing.
  • Water trapped in areas around your shower or bath.
  • Damp air seeping through the walls of your home or even your concrete foundation.
  • Condensation such as from near your shower or even your windows.

Signs of Wet Rot

There are a variety of symptoms that may signal wet rot setting into your home’s wooden structures. Here’s some of the most common signs of wet rot that you may encounter:

  • Discoloration in your wood—the affected area may look darker or lighter than the rest of the wood. This is because there is white wet rot and brown wet rot.
  • Change in the wood texture—the affected area of the wood structure may feel soft and bouncy, almost like a sponge.
  • When dry, the wood looks cracked and close to falling apart if touched.
  • There is an earthy, damp smell in the air.
  • Paint flaking off your walls can also be a sign of wet rot.

Different types of wood rot exhibit different signs and you may need a professional to help you accurately identify it so that the problem can be properly resolved.

Differences Between White Wet Rot and Brown Wet Rot

There are several species of fungus that make up what’s called wet rot. In the United States, one of the most common species of wet rot fungus is cellar fungus, also known as Coniophora puteana. But these different species of wet rot fungus can be divided into two groups based on their appearance: white rot and brown rot. Let’s take a look at why:

  • White Rot
    • Along with its light or whiter appearance, white rot also tends to have a soft and spongy kind of feel. This is because of how white rot works to degrade and consume what’s called lignin in the wood. Lignin is what gives wood it’s rigidity, so when it gets consumed by the white rot, it leaves the wood feeling soft.
  • Brown Rot
    • As the name suggests, brown rot has a darker appearance and sometimes can blend in with the color of the wood it’s growing on. These kinds of wet rot fungi are unable to consume the lignin in wood, only alter the lignin as they try to get to the sugars and cellulose.

Where Can Wet Rot Be Found?

The typical sites where wet rot occurs range from roofs and attics to cellars, crawlspaces, and basements. It can also show up in the wood of your window frames. But there are other parts of your home that wet rot could appear—if you have wooden structures that should become exposed to prolonged moisture elsewhere in the house, such as from a plumbing leak, wet rot will have a chance to appear just as well.

Wet Rot: How to Fix It?

First and foremost, you should try finding out where the source of moisture is located so that a reoccurrence doesn’t happen. Once you’ve located and resolved the moisture problem, you’ll be able to treat the affected area of wood with a fungicide. There are also products such as wood hardeners for wet rot situations but be sure to use that fungicide to get rid of the wet rot fungus.

Should the wet rot be severe enough, however, then the wood may need to be replaced, preferably with fungicide treated wood.

You should also consider preventative measures to protect your home from future moisture problems such as waterproofing and foundation repair. This can protect your cellars, crawlspaces, and basements from wet rot and the damages it can cause.


Dry Rot

An up close look at Dry Rot
An up close look at Dry Rot

What Is It?

While most brown rots are categorized as wet rots, there is a variety of brown rot fungi that cause what we know as dry rot. The reason for the term “dry rot” is because of how the fungi like Serpula lacrymans require less moisture than the other white and brown rots. While wet rots generally require a moisture content of around 50%, dry rot only requires around 20% to 30% moisture content to begin growth. Dry rot also gets its name from the appearance it gives the affected wood: dried and cracked.

Common Causes of Dry Rot

Similar to wet rot, dry rot can be caused by linger moisture caused by some fault in your building’s construction. Here’s a list of common causes for dry rot:

  • Elevated levels of damp and humidity
  • Poor ventilation in the house
  • Leaking gutters
  • Moisture seeping through walls

Signs of Dry Rot

During the early stages, dry rot may be hard to spot as their spores activate and begin to grow hyphae, white strands that penetrate into the wood like roots and begin breaking the lumber down. But when enough of these hyphae grow, eventually they will gather together until they become a visible mass known as mycelium. This is when you will likely first detect the presence of dry rot.

The dry rot mycelium will resemble something like a strange cotton-like substance on the wood. At this stage, it will begin to spread to further infiltrate and break down more wood for nutrition and growth.

Eventually, the dry rot will become a mushroom-like fruiting body that will begin producing new spores to release. This is when dry rot becomes the most obvious.

Throughout the process, the affected wood will likely show symptoms such as:

  • The wood looks very dry and brittle, like it may crumble at the slightest touch
  • Wood splitting and cracking into small pieces, they may look blocky like cubes
  • The wood may have shrunk—wooden structures affected may lead to bouncy floors, loose supports, and creaky floorboards
  • The wood looks discolored, darker
  • Dry rot carries with it a musty and earthy smell
  • Appearance can range from fluffy white mycelium to fruiting bodies that resemble a cross between a mushroom and a pancake
  • Fruiting bodies will have red coloration or red dust particles—these are spores that will be released to help the fungus spread
  • Can also appear as yellow or grey-white patches on the wood surface

Where Can Dry Rot Be Found?

Dry rot can be found in a number of places in your home. So long as wood is present and enough moisture is available, dry rot can grow in your home’s walls, floors, and supports. Dry rot is also capable of surviving and growing in masonry and plaster so long as enough moisture is present—this is why dry rot can be more troublesome than wet rot.

Dry Rot: How to Fix It?

After dry rot has been detected, you’ll want to first determine the source of moisture that helped it grow in the first place. Once that source of moisture has been addressed, you’ll need to take these steps to free your home of dry rot:

  • Identify all affected areas of wood
  • Clean nearby surfaces with fungicide to eliminate spores and other traces of dry rot
  • Replace the affected wood with new wood that has been treated with fungicide
  • Nearby masonry must also be cleaned and treated

Preventative measures should be taken to ensure that another moisture problem doesn’t occur that can cause dry rot to return. Consider speaking with a professional about waterproofing and foundation repair to prevent excess moisture from entering your home.

Preparing Your Home Against Wood Rot

Wood Rot Fungicide
’58 Foundations Specialist treating wood with fungicide to prevent wood rot

As the saying by Dutch philosopher Desiderius Erasmus goes, “Prevention is Better Than Cure”. Having wood rot in your home can compromise the structural integrity of your home and result in costly repairs. As with many other species of fungi, those responsible for wet rot and dry rot are reliant on moisture to activate their spores and begin their life cycle. By controlling the moisture in your home and prevent moisture-related problems from occurring, you can keep your home free from wood rot for many decades.

Whenever it rains, much of that water comes to rest against the sides of your home’s foundation. Should the hydrostatic pressure be too great, it could lead to moisture seeping through your foundation, or worse, cause a crack that can lead to greater leaks and more moisture invasion. Not only can it cause water damage to your foundation and lower level, but that excess moisture can make its way to the rest of your home and into the wooden structures, resulting in wood rot.

Here are some ways that you can fortify your home against invasive moisture, so that wood rot is kept at bay:

  • Crawlspace or Basement waterproofing
  • Repair your foundation of cracks and other damage
  • Maintain and clean your rain gutters
  • Improve the grading around your house so that the land slopes away
  • Extend your downspout
  • Treat your wooden structures with fungicide to prevent infestation and outbreaks of wood rot
  • Use a dehumidifier to better control the moisture in the air of your home

There’s no telling whether your home will be struck by wet rot or dry rot. Due to their difference in moisture requirements, it is important to maintain proper moisture levels in your home to ensure that neither has the chance to take root and compromise your wooden structures.

The reality is that fungi, especially wood rot fungi, will always be a factor in the lives of homeowners. They will always be a part of our world as one of the ruling groups of decomposers. Scientists around the world are still trying to better understand the precise ways that white rot and brown rot fungi interact with different types of wood. As concluded by a study on SpringerNature, “Understanding the moisture requirements of decay fungi is key for interpreting wood durability test data, for analyzing the protective mode of action of new wood protection systems and for accurate modeling of degradation processes and the resulting service lifetimes of wood products.”

One day, we may have the improved knowledge to build homes that can better ward off wood rot. Until then, it pays to be proactive in preventing wood rot from taking place at all.

Wood Rot Fungi and Humanity

The presence of fungi on our planet extends hundreds of millions of years before the dinosaurs and will likely be here long after humans are gone. This also goes for wood rot fungi, as the environment provides more than an ample supply of means to survive, and it plays a vital part in the circle of life. As explained on, “Lignin accounts for 30 percent of the organic carbon on Earth. Therefore, white-rot fungi—the most efficient lignin-degrading organisms—play a critical role in the movement of carbon from the atmosphere to organisms and vice versa.” But perhaps there is a way that we can go beyond just fighting wood rot as a potential peril of homeownership. Maybe we can make use of the way these fungi live.

On, goes on to describe how brown rot fungi can serve practical purposes for our future, “Understanding the two-step mechanism could lead to new biotechnology approaches. With these approaches, scientists could turn wood cellulose into biofuels or bioproducts—efficiently and cost-effectively.” Wood rot fungi may play a role in our departure from an oil-based economy as science continues to learn more about them.

While we are still researching into roles that wood rot fungi may play in our future and how we may better coexist with these fungal species, it doesn’t mean we have to let them wreak havoc in our homes. Take action against invasive moisture so that wood rot fungi can do their job elsewhere, while you enjoy the safety and comfort of your home! Give us a call at (866) 485-6695 and we’ll have a specialist provide you with a basement waterproofing or crawlspace repair estimate and a zero-obligation price estimate!


Sources for Links:

Hungry Fungi: White-Rot Fungi Eat All Components of the Wood They Decompose

Understanding How Brown Rot Fungi Degrade Wood Could Lead to New Tools for More Efficient Biofuel Production

Wood-Water Relationships and Their Role for Wood Susceptibility to Fungal Decay