How to Stop Wood Rot From Spreading
Got wood rot? Cut it out
Removing the damaged wood is the first step in stopping wood rot.
Wet wood rot requires a lot of moisture, whereas dry rot does not.
Using pressure-treated wood can reduce the risk of wood rot.
- Chisel
- Utility knife
- Power drill (optional)
- Putty knife (optional)
- Sanding block (optional)
- Wood hardener
- Wood putty (optional)
- Fungicide (optional)
Wood rot is a fungal infection that sets into damp wood, and it can spread quickly once it does. Although wood rot is not usually harmful to your health, it can cause wood to become soft or brittle. If the damage is extensive on a support post or beam, there could be a threat to your home’s structural integrity. Let’s discuss how to stop wood rot from spreading so that you can mitigate the damage to your home.
Identify and Address the Source of the Moisture
Wood rot is caused by a fungal infection, but the fungus responsible for the rot will only take root in wood that has a moisture content of 20% or higher. If you’re dealing with wet rot and not dry rot, eliminating the source of the moisture can stop the infection from worsening and spreading to other nearby wood sources. As such, your first order of business should be to figure out where the water or humidity is coming from and get a solution in place right away.
This solution could involve hiring a local plumber to repair a pipe leak, a window specialist to replace a leaking window, or a roofer to patch a roof leak. If you can’t identify the source of the moisture yourself, call a water damage restoration company near you for help. Dry rot repair costs can be quite high, but ensuring the damage doesn’t continue getting worse is well worth the investment.
Dry the Area
Next, you should dry the area to prevent mold growth, which can contribute to the damage and even create health issues. If you find signs of water damage and wood rot inside your home, use a wet-dry shop vacuum to remove standing water and puddles, and then run blower fans and dehumidifiers for 24 to 72 hours to remove moisture and prevent mold growth after water damage.
Identify the Type of Wood Rot You’re Dealing With
Photo: JulieWestlind / Adobe StockNext, you should take a step back and try to identify the type of wood rot you’re dealing with, as different types demand different solutions.
Wet rot will smell moldy or musty, the wood will feel soft or pliable, and you may notice white-colored mushrooms growing on the wood. If the resulting damage is minimal, you may be able to stop here, as wet rot won’t continue to do damage once you dry out the wood. If the damage is more severe, though, be sure to continue with the following steps.
Dry rot will smell earthy or mushroomy, the wood will look crumbly or have cubical fault lines on the surface, and any mushroom growth will have a brown or orange coloration. Dry rot can continue spreading through wood even after you dry it out, so you’ll need to remove any affected wood and repair or replace it.
Apply Wood Hardener
Use a foam brush or the included applicator to apply wood hardener to the affected area. Be sure to wear a respirator, gloves, safety goggles, long sleeves, and pants, and always work in a well-ventilated area. Wood hardener contains high levels of volatile organic compounds that can irritate skin and eyes, creating fumes that can be dangerous to inhale. You may want to consider hiring a local handyman service for this part to keep yourself safe.
Apply a Sealant
Finally, apply a waterproof sealant over the wood. For outdoor wood, consider an oil-based polyurethane or a marine varnish for maximum protection. For indoor wood, you can use a water-based polyurethane or leave the wood bare, especially if you removed the source of the moisture. To help prevent wood rot issues in the future, you can opt for a wood sealer that includes a fungicide to help keep wood rot fungus at bay.
Common Areas to Find Wood Rot
Some of the most common areas to find wood rot include damp basements, under leaky windows and doors, under roof leaks, behind plumbing fixtures, on any outdoor wood that’s in direct contact with the ground, and in shady, wet outdoor areas. Dry rot doesn’t require much moisture to thrive, so it can be found anywhere on your property where there is wood and even small amounts of moisture.
What does dry rot look like? Dry rot often has rusty-colored mushroom-like structures on the wood. It grows larger and spreads faster than wet rot. Dry rot makes the wood appear brittle and crumbly.
Wet rot often has off-white mushroom-like structures that are smaller than dry rot’s fruiting bodies. It creates soft and spongy wood.
Though the terms are used interchangeably, wood rot and dry rot have different meanings. Wood root is a broad term that describes various types of fungal decay in wood, while dry rot is a specific type of wood rot caused by the fungus Serpula lacrymans. Dry rot can thrive at a low moisture level and spread rapidly across plaster and even masonry to infect new areas of wood.
Signs Wood Rot Is Spreading
You can look out for a few things that indicate that wood rot is spreading.
White “cobwebs” spanning out over the surface of the wood: Before the fungus that causes wood rot starts growing mushrooms, you’ll notice white growth on the surface that looks like cobwebs. If this growth continues spanning over the surface after treatment, your wood rot is spreading.
Darker areas of wood that grow larger: Since wood rot fungi requires moisture to set in, you may notice wet areas of wood that look darker before the fungi take hold. This indicates a moisture issue and not necessarily wood rot, but it often leads to rot.
More mushrooms forming on the wood: You may find that areas of the wood with mushrooms growing on them continue to get larger. This is a sign that the mycelium of the fungi growing inside the wood is taking up more and more of the material.
Signs of wood rot on nearby materials: If you notice any of the above signs on nearby wood or even drywall or plaster that weren’t there initially, it’s a sign that the rot is getting worse.
The source of moisture isn’t addressed: Wet rot will continue worsening as long as there’s moisture in your wood, and dry rot can return if you cut out the affected area but don’t address the underlying moisture problem. Where there is moist wood, there will eventually be wood rot, so a source of moisture is a sign that rot will set in.
How to Prevent Wood From Rotting
Getting rid of wood rot can be tricky and expensive, so it’s better to prevent it from setting in in the first place. There are a few things you can do to help avoid wood rot problems.
Keep your wood dry. Wood rot fungus can only form where there’s moisture. Correct leaks and moisture issues immediately to keep wood dry and prevent rot.
Keep wood away from the soil. Soil naturally holds onto moisture, so any ground-contact lumber will eventually rot. Use gravel or other drainage material beneath ground contact wood to avoid moisture from wicking up into it.
Apply and reapply sealants. Waterproofing sealants are your best option for avoiding wood rot on outdoor wood. Use waterproof paint, oil-based poly, marine varnish, or other sealants specifically made for exterior use. Plan on reapplying every one to two years.
Reduce the risk of infection. Tree stumps, wet firewood stacks, and even wood chips can get infected by wood rot fungus, which makes it more likely to infect wood in and around your home. Remove these items or keep them dry to reduce your risk.
Use pressure-treated wood. Pressure-treated wood contains chemicals that naturally resist fungal growth. It’s best for any outdoor projects that will see exposure to moisture and runoff.
Keep plant growth away from the wood. Finally, trim trees away from fascia boards and bushes away from window and door trim. Plants hold moisture against wood, so maintaining some distance can avoid moisture problems.
DIY vs. Hiring a Pro to Repair Wood Rot
It’s possible to DIY minor wood rot issues, especially if the damage is only topical and on decorative wood, like window or door trim. Just be sure to identify and correct the source of moisture before you begin, and wear the proper safety gear when working with wood hardener.
You should hire a water damage restoration expert if you can’t identify where the moisture is coming from, if you have major damage that goes beyond the surface, or if you suspect you have dry rot that may have spread too much to contain on your own. Finally, always call a professional if you find signs of wood rot on structural components, as making mistakes and not eradicating the infection could lead to expensive and dangerous structural damage and instability in your home.
Frequently Asked Questions
Black mold and wood rot are both types of fungi that form in damp or wet areas, but they cause different problems. Black mold grows on the surface of wood or other materials, while wood rot affects the structure of the wood material. Additionally, inhaling or contacting toxic black mold spores can make people sick. Wood rot spores are not known to cause illness in humans.
Water damage doesn’t always cause mold and wood rot, but it can. Both mold and wood rot require moisture in the wood to form, so water damage that continues to leave water or moisture behind can lead to both issues. Water damage and mold often go hand-in-hand, but you can prevent mold growth after water damage by addressing the source of moisture and drying out the area quickly. The same goes for wood rot. The longer you let water damage go, the higher the risk of mold and rot.
Learning how to repair rotted wood is something that you can do after stopping existing wood rot from spreading. After removing the wood rot, you can put new wood in place of the ruined wood or use wood putty to repair minor damage. However, because wood rot is difficult to eradicate without expert help, you may want a professional to do it. Do not attempt repairs in the area until you are certain that all the damaged wood and signs of wood rot are gone.
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