Wood Rot 101: What It Is, Where to Find It, and How to Fix It

by Joost Nusselder | Updated on:  June 13, 2022
I love creating free content full of tips for my readers, you. I don't accept paid sponsorships, my opinion is my own, but if you find my recommendations helpful and you end up buying something you like through one of my links, I could earn a commission at no extra cost to you. Learn more

Wood rot is a type of decay that occurs in wood. It is caused by fungi, bacteria, and insects that feed on the wood. Wood rot can weaken the structure of a building and make it more susceptible to damage from wind, rain, and snow.

There are three main types of wood rot: brown rot, white rot, and soft rot. Brown rot is the most common type of wood rot, and it results in the wood turning brown or black. White rot turns the wood white or yellow, and soft rot causes the wood to become spongy and weak.

Wood rot can be prevented by treating the wood with a preservative, such as boric acid. Preserving the wood will not only prevent rot, but it will also extend the life of the wood.

What is wood rot

Wood Rot: A Fungal Infestation That Can Break Down Your Structure

Wood rot is a natural process that occurs when wood is exposed to moisture and fungi spores. When wood is damp for a prolonged period, it creates the ideal conditions for wood-eating fungi to form and spread. The fungi digest parts of the wood that give it strength and stiffness, ultimately resulting in decay.

Types of Wood Rot

There are two commonly recognized types of wood rot: dry rot and wet rot. Dry rot is caused by a specific type of fungus that can survive in very low moisture content, while wet rot is caused by a range of fungi that require higher moisture levels to thrive.

How Does Wood Rot Affect Your Building?

Wood rot can affect any part of a building that is made of wood, including the structural elements, finishes, and decorative features. It can start in a small area and spread throughout the entire body of the wood, leaving it weakened and vulnerable to breakage.

How Does Wood Rot Start?

Wood rot starts when wood is exposed to moisture for a prolonged period, creating the ideal conditions for fungi spores to form and spread. The fungi digest parts of the wood that give it strength and stiffness, resulting in decay.

How Can You Notice Wood Rot?

Wood rot can be pretty hard to notice at first, but there are some signs that you can look out for. These include a musty smell, a soft or spongy feel to the wood, and a lack of structural integrity.

What’s the Difference Between Dry Rot and Wet Rot?

Dry rot and wet rot are similar in that they are both caused by fungi that break down wood. However, there are some key differences between the two:

  • Dry rot is caused by a specific type of fungus that can survive in very low moisture content, while wet rot is caused by a range of fungi that require higher moisture levels to thrive.
  • Dry rot is more commonly found in buildings, while wet rot is more commonly found in fresh wood.
  • Dry rot is more widely recognized and classified than wet rot, which has numerous types and effects.

Why is it Important to Learn About Wood Rot?

Learning about wood rot is important because it can have significant effects on the structure of your building. If left untreated, it can ultimately result in the need for costly repairs or even the complete replacement of the affected wood. By understanding how wood rot works and how to prevent it, you can ensure that your building remains strong and stable for a long time to come.

The Perils of Rotted Wood: How to Identify and Deal with It

Identifying rotted wood can be a guessing game, but with a trained eye and appropriate aids, it’s possible to determine the culprit. Here are some general practices to aid in identifying rotted wood:

  • Check previously damaged areas or patches of dampness.
  • Look for soft, shrunken, or rotten boards.
  • Check for cracks, splintering, and textures that have begun darkening.
  • Continuous fungal growth or musty smells are also signs of rotting.

Dealing with Rotted Wood

Once you’ve determined that you have rotted wood, it’s important to take action to remedy the issue. Here are some steps to take when dealing with rotted wood:

  • Determine the cause of the rotting. Is there a leaky pipe or a moisture issue?
  • Remove the affected wood and replace it with new timber.
  • If the rotting has spread, it may be necessary to call in a professional to assess the damage.
  • Be sure to take care of any moisture issues to prevent future rotting.
  • If caught early, rotted wood can be peeled away and the area can be treated with a fungal remedy.

Remember, identifying and dealing with rotted wood is an important part of maintaining the safety and integrity of your home. By keeping an eye out for the signs of rotting and taking appropriate action, you can ensure that your home remains a safe and healthy place to live.

Understanding the Culprits Behind Wood Rot

Wood rot is caused by fungal growth in damp wood. This fungal growth is triggered when timber becomes damp enough to have 20% or more moisture content, and isn’t able to dry out quickly or is repeatedly dampened. The fungi that cause wood rot are naturally present in the environment and are classified as either dry rot or wet rot, depending on the type of moisture that creates the ideal conditions for their growth.

The Role of Cellulose in Wood Rot

Cellulose is a natural element found in wood that gives it its structural function. When wood is exposed to moisture, the cellulose breaks down, creating the ideal conditions for fungi to grow. The fungi feed on the cellulose, ultimately resulting in the decay of the wood.

The Effects of Wood Rot on Buildings

Wood rot can affect the structural integrity of a building and cause significant damage if left untreated. It can weaken the wood to the point where it breaks or falls apart, resulting in costly repairs. The effects of wood rot can be seen in the finishes of a building, such as peeling paint or warped wood.

Recognizing and Preventing Wood Rot

It’s important to note that wood rot can go unnoticed for a long time, as it often starts in areas that are not visible or easily accessible. However, there are some common signs to look out for, such as a musty smell, soft or spongy wood, and fine brown dust. To prevent wood rot, it’s important to keep the wood dry and well-ventilated, remove any fallen leaves or debris that can trap moisture, and hire a professional to inspect the wood on a regular basis.

The Scientific Process of Wood Rot

The process of wood rot starts with the presence of moisture, which creates the ideal conditions for fungi to grow. The fungi then feed on the cellulose in the wood, breaking down its structural integrity. As the fungi grow, they produce spores that can spread and carry the rot to other parts of the building. Ultimately, if left untreated, wood rot can result in the need for significant repairs or even the replacement of the affected wood.

Dry Rot vs Wet Rot: What’s the Difference?

Dry rot and wet rot are two types of fungal growth that can affect wood and masonry in buildings. While they both require moisture to grow, there are some key differences between the two:

  • Dry rot is a more serious form of decay that can spread onto and destroy much of the timber in a property. Wet rot, on the other hand, is less serious and is usually confined to where the timber becomes and stays wet.
  • Dry rot is associated with a specific type of fungus, while wet rot can be caused by a range of fungal species.
  • Dry rot spores can remain dormant for long periods of time until they come into contact with moisture, while wet rot spores require a constant source of moisture to grow.
  • Dry rot can spread quickly and cause significant structural damage, while wet rot is relatively slow-growing and usually only affects the surface layers of timber.

How to Identify and Remove Dry and Wet Rot

Identifying the presence of dry or wet rot in a property can be a highly technical process that may require the help of a professional. However, there are some signs that you can look out for:

  • Dry rot often appears as a white or greyish growth that can spread quickly and concentrate in certain areas.
  • Wet rot is usually associated with a leak or other source of moisture and can cause affected timber to become soft and spongy.
  • If you suspect that your property may have dry or wet rot, it’s important to confirm the presence of the fungus before taking any action.

Removing dry or wet rot from a property may require a range of treatments, depending on the severity of the problem. Some possible options include:

  • Replacing affected timber with new, sound timber.
  • Using treatments that concentrate on killing the fungus and preventing its feeding on the timber.
  • Clean and dry the affected area, and stop any leaks or sources of moisture that may be causing the problem.
  • Applying a masonry treatment to prevent the spread of dry rot into brickwork or other masonry.

Preventing Dry and Wet Rot

Preventing dry and wet rot from occurring in the first place is the best way to avoid the need for costly repairs. Here are some tips for preventing fungal growth in your property:

  • Ensure that your property is well-ventilated and that any sources of moisture are properly sealed.
  • Regularly check for signs of leaks or other sources of moisture and address them promptly.
  • Use a professional to check for dry and wet rot on a regular basis, especially if your property is older or has a history of water damage.
  • Consider using treatments that can help to prevent the growth of dry and wet rot, such as those that contain boron or other fungicides.

In conclusion, while dry and wet rot may seem similar, they are actually quite different in terms of their causes, effects, and treatments. By understanding the differences between the two and taking steps to prevent their growth, you can help to ensure that your property remains sound and free from fungal decay.

How to Spot Wood Rot Like a Pro

  • Walk around the perimeter of your home and check for any signs of damage or discoloration on the siding, windows, and roof.
  • Look for swelling or paint that is peeling away from the wood.
  • Check the gutters and downspouts for excessive moisture or rotting.

Perform a Test with a Screwdriver

  • Poke the wood with a sharp tool like a screwdriver to see if it feels soft or spongy.
  • If the wood is firm and hard, it’s probably not rotting.
  • If the wood sinks in or breaks away easily, it’s a sign of rot.

Use a Flashlight to Detect Hidden Rot

  • Shine a flashlight on the wood to detect any hidden rot.
  • Check the edges and joints of the wood where rot is most likely to form.
  • Look for mold or fresh wood shavings, which are signs of recent rot.

Get a Professional Opinion

  • If you’re not sure if you have a wood rot problem, it’s best to get a professional opinion.
  • A contractor or home inspector can perform a more thorough examination and help you determine the best course of action.

Prevent Wood Rot from Happening

  • Annual weatherproofing can help protect your wood from moisture and rot.
  • Remove any standing water around your home and add gutters if necessary.
  • Prime and paint your wood to hide any spots where moisture can seep in.
  • Slope the ground away from your home’s foundation to prevent water from pooling.
  • Use treated wood or a protective coating to prevent rot from taking hold.

Wood rot can start anywhere there is wood and moisture. However, some areas are more prone to attack than others. The following are the primary areas where wood rot can take hold in your home:

  • Exterior trim, including fascia boards, window sills, and door frames
  • Decks and porches
  • Roofing and siding
  • Attics and crawl spaces
  • Bathrooms and kitchens
  • Basements and foundations

Dealing with Wood Rot: A Comprehensive Guide

The first step in dealing with wood rot is to identify the type of rot that has affected your structure. There are two main types of wood rot: dry rot and wet rot. Dry rot is caused by a fungus that attacks the wood’s cellulose content, while wet rot is caused by a variety of fungi that thrive in moist conditions. Here are some ways to identify the type of wood rot:

  • Dry rot: This type of rot usually appears as a white, powdery substance on the surface of the wood. The affected wood may also be lighter in color and may crumble easily when touched.
  • Wet rot: This type of rot usually appears as a dark, damp area on the surface of the wood. The affected wood may also be darker in color and may feel spongy or soft to the touch.

Inspect the Affected Areas

Once you have identified the type of wood rot, it’s time to inspect the affected areas to determine the extent of the damage. Here are some things to look for:

  • Check for any changes in the texture or color of the wood.
  • Look for small, white or dark spots on the surface of the wood.
  • Grab a screwdriver or other pointed tool and try to poke it into the affected area. If the wood feels soft or crumbly, it’s likely that the rot has spread deeper into the structure.
  • Test the strength of the wood by applying pressure to it. If it feels weak or gives easily, it’s probably been affected by rot.

Remove the Affected Sections

Once you have identified the affected areas, it’s time to remove the rot. Here’s how to do it:

  • Use a saw or other cutting tool to remove the affected sections of wood. Make sure to cut away any portions of the wood that have been affected by rot, as leaving even a small amount of rot behind can cause it to spread.
  • If the rot has affected a structural element of the building, such as a beam or joist, it may be necessary to replace the entire element.

Prevent Future Problems

After you have removed the affected sections of wood, it’s important to take steps to prevent future problems. Here are some things you can do:

  • Keep the wood as dry as possible. This can be done by ensuring that the building is properly ventilated and that any leaks are repaired promptly.
  • Use materials that are less likely to be affected by rot, such as pressure-treated lumber or naturally rot-resistant woods like cedar or redwood.
  • Perform regular maintenance on the building to ensure that any potential problems are caught early.
  • If you’re not experienced in dealing with wood rot, it’s always a good idea to consult with a professional to ensure that the job is done correctly.

Preventing Wood Rot: How to Keep Your Home Safe and Sound

Once you’ve addressed the potential causes of wood rot, the next step is to keep your wood clean and dry. Here are some tips:

  • Clean your wood regularly to remove dirt and debris that can trap moisture and cause damage.
  • Check your wood for signs of rot or damage regularly, especially in areas that are exposed to moisture.
  • If you have exterior timber that’s exposed to rain or moisture, consider applying a protective coating to help keep it dry.

Work with a Professional

If you’re not sure how to prevent or fix wood rot, it’s always best to work with a professional. They can help you identify the type of rot you’re dealing with and offer the best solutions for your specific situation. Here are some things to keep in mind:

  • Make sure you find the right professional for the job. Not all contractors are experienced in dealing with wood rot, so it’s important to do your research and find someone who has the necessary expertise.
  • Don’t be afraid to ask questions. A good professional will be happy to explain the work they’re doing and why it’s necessary.
  • Be prepared to pay a higher price for quality work. While it may be tempting to go with the cheapest option, making sure the job is done right the first time will save you money in the long run.

Take Action

Preventing wood rot is an important task for any homeowner, but it’s especially important if you live in an area that’s prone to moisture or if you’ve had problems with wood rot in the past. Here are some steps you can take to get started:

  • Set aside some time to check your wood for signs of rot or damage.
  • If you find any areas that need attention, take action right away to prevent the rot from spreading.
  • Consider installing a moisture barrier or other protective measures to help keep your wood dry and prevent future problems.

Remember, preventing wood rot is a task that requires ongoing attention and care. By taking the steps described above, you can help ensure that your home stays safe and sound for years to come.


So, wood rot is a fungal infestation that affects wood. It’s a natural process, but can be prevented by maintaining the moisture levels of the wood. You should look out for the signs of wood rot, and get it checked by a professional if you suspect any. So, don’t be afraid to ask! You can do it! Just remember to use this guide as a reference and you’ll be fine.

I'm Joost Nusselder, the founder of Tools Doctor, content marketer, and dad. I love trying out new equipment, and together with my team I've been creating in-depth blog articles since 2016 to help loyal readers with tools & crafting tips.