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wood rot

Wood Rot

Wood rot can have a dramatic, terrible effect on your home. Learn these problem signs, so you can catch the red flags early and get your property back into good health.

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Crawl spaces are known for having issues with humidity, and increased levels of moisture can cause wood rot. This may not seem a big deal, especially because crawl spaces are often a forgotten part of housekeeping, but it has a great impact on your home’s structure. 

Rotten wood can cause a slew of problems in your home, such as high energy bills, uneven floors, jammed doors, and cracks on your wall. Many homeowners have to continuously fix these issues in their homes without ever knowing what the true cause is. Luckily, wood rot has very obvious problem signs you can detect, so you can spot them early. 

Take action before things get too bad. Here’s everything you need to know about detecting wood rot in your crawl space. 

wood rot

How to Detect Wood Rot in Your Crawl Space 

If you have a crawl space with vents or if you have constant flooding problems in said crawl space, it’s quite possible you have wood rot. Even if you keep your crawl space clean and tidy, and the wooden structure is brand new, if it’s not fully waterproofed, the humidity has probably already started to take over. 

When thinking of taking care of a home’s structure, many homeowners don’t think about the crawl space. It’s meant to separate the home from the damp or frozen ground and to provide easy access to plumbing and electrical wiring. If it’s doing its job and all the pipes below are working, why check up on it? 

Well, your crawl space’s condition matters a lot more than you think. Here are all the problem signs you should look out for to determine whether or not your crawl space’s wood is rotting. 

Mold and Fungi on The Wood 

It’s no secret that humidity causes mold growth. However, when most homeowners think of mold and fungi, they only picture it as a surface-level growth—something that can be removed and scraped off. Although some fungal growth can be surface level only, some of it, especially the kind that causes wood rot, grows internally in structures. 

Wood is absorbent, so it contains moisture if it’s in a humid space. From there, the mold will grow and will begin debilitating the wood until it weakens and breaks apart. 

There are different types of mold and fungal growth that happens on wood, such as: 

  • Brown Rot  

Dry rot got its name because many believed that it was a fungal growth that did not need water to survive. We have since learned that this is not the case, so it was given the alternative name “brown rot,” though it will still be called dry rot from time to time. Its scientific name is Serpula Lacrymans. 

When rotting due to brown rot, wood will be broken apart into squares or rectangles. It isn’t spongy or soft like most fungi are known to be, and the wood looks dry despite the moisture. Brown rot is often confused for termite damage. This type of fungus is capable of absorbing moisture from afar, so even if you think the humidity levels aren’t all that high in the crawl space, as long as there is moisture in the air, the fungus will grow. If spotted in time, wood with brown rot can be saved. 

  • Red Dust  

Red dust on wood is a sign of brown rot. It’s a great way to differentiate if your wood is actually rotting or is infested with termites. The red dust is fungal spores on the surface of the wood. In this condition, the fungus hasn’t fully grown yet and is waiting for the proper humidity levels in order to do so. 

If you find red dust on wood and you dust it off, don’t think that the fungus is gone. Remember, the fungus has internally affected the wood’s structure and is doing heavy damage from within. If you remove the red dust, it’s likely you’ll find more a few days later. 

  • Decay Fungi  

Decay fungi look a little more like regular fungi. It makes the wood soft and squishy to the touch. It shrinks the wood, which spells trouble for your home. The shrinkage that occurs with this fungus is detrimental to your house’s structure. Without the strength and size of a healthy wooden beam, the property will begin to sink. 

Damage to wood caused by decay fungi almost always needs to be replaced. There’s no going back once the wood isn’t solid anymore, so if you don’t have an encapsulated crawl space, constant check-ups need to be done, so you don’t have to spend all that money replacing the wood. 

  • Surface Mold  

Surface mold is the kind that only affects the wood superficially. It doesn’t harm the wood’s internal structure and the most it will do is cause discoloration. That said, just because it doesn’t damage the wood doesn’t mean that everything is fine with your crawl space’s condition. The kind of mold that only affects wood superficially might be indicative of humidity that could affect other parts of the crawl space, such as the soil or the concrete. 

Concrete is permeable, meaning it can absorb moisture. When concrete absorbs moisture, it runs the risk of pitting and flaking, especially if said moisture was absorbed during the winter, what with the freeze-thaw effect. This can lead to cracks and breakage in the concrete, which cause as much structural damage to the home as rotten wood. 

House Structure 

A house with a crawl space is supported by the concrete and wood that the crawl space is made of. As soon as said concrete and wood start to fail, the house lacks proper support. If the damage becomes too severe, you’ll have to repair more than just the crawl space. 

  • Uneven Floor  

A good indication of wood rot is sagging and uneven floors. Because the wooden supports are weak and soft, they are unable to hold up the flooring. Sagging floors aren’t very noticeable at first, but you definitely don’t want to get to the point where you do start to notice. If the sinking is too severe, there will be little you can do to salvage the wood in the crawl space. 

Summer is North Carolina’s most humid season. During the summer, you’ll want to continuously check the supports in the crawl space. Fungi take up to 10 days to germinate and deteriorate the wood, though nothing will be visible for at least 21 days. To avoid having to replace the wood completely in both the crawl space and your home, touch the wood every few days to determine its soundness. You can also use a level ruler to check the floor’s evenness, but this can get tiring after a while, especially if you have a big house. 

If you have no waterproofing done on your crawl space, this will be a year-round problem. You would have to check the crawl space repeatedly and it will be a concern until some waterproofing renovation is done. 

  • Jammed Doors 

If your doors won’t close properly and they keep getting jammed, you might need to check your crawl space. Because wood rot affects the support beam’s abilities to hold the house up, the floor begins to sink. This can cause your doors to jam and stop working properly either because of the uneven floor or the uneven door frame. 

  • Cracked Pillars and Walls 

As the floor sinks, the pillars in the house begin to settle. This causes cracks and breakage because the pillars are unable to support the rest of the house without a proper foundation. If you have an uncovered crawl space, especially one with vents, and your pillars and walls are cracked, you’ll need to do more than just fix the cracks. 

  • Plumbing Issues  

When pipes get wet and the water freezes, they run the risk of bursting over time. Water expands by about nine percent once frozen, and this breaks apart the pipe’s structure. If you frequently have problems with frozen pipes under the crawl space, it’s possible you’ll experience problems with the wood in due time. 

Other Methods 

There are other ways to tell if your wood is rotting that don’t have to do with the structure of your house or the wood itself. If you have an uncovered crawl space and have been living in your house for a long time, you may have gotten used to the following signs. However, as insignificant as the signs may seem, they indicate a much bigger problem that should be looked into.  

  • Smell and Humidity 

Because of the stack effect, 50 percent of the air you breathe in your home comes from the crawl space. The air in crawl spaces is always a bit warmer than the air in your home. Hot air always travels to where it’s colder because it’s less dense, so the air in the crawl space rises and invades the space above it. 

When a crawl space is humid and full of mold, all that musty air will rise. If your home has above average humidity levels and the air smells old and moldy, it’s possible it’s coming from the crawl space. Smelling all that polluted air is bad for your throat, lungs, and sinuses in the long run, so keeping the humidity levels in your crawl space as low as possible is a must. 

  • Concrete  

If you are unable to access your crawl space to check the wood itself, you can always check the concrete surrounding your crawl space. Concrete is permeable and can hold moisture as much as wood does. 

There are several ways of checking the moisture content in concrete. Visually, you can check for any kind of discoloration. Depending on how the concrete was mixed, moisture can cause a chemical reaction that brings out the salt content in the concrete, which causes discoloration and staining. You can also check for concrete pitting, which is when the surface layer of concrete begins deteriorating because of the freeze-thaw effect. If the concrete surrounding your crawl space is unsound due to high levels of moisture, it’s very likely that your wood is too. 

Wood trot


Most crawl spaces in North Carolina are equipped with vents. This is because of the common misconception that the humidity in a crawl space can be aired out. Local building laws have yet to be rewritten to reflect what contractors now know is true: that it’s impossible to air out a crawl space and it’s better to try to keep the moisture out completely. 

Complete waterproofing of your crawl space can seem like a daunting idea, so you might try to go for something a little simpler. However, when it comes to humidity in your crawl space, less isn’t more. 

  • What Vent Covers Do and Don’t Do  

Vent covers are placed over your vents to cover them up. They come in different sizes and materials and are pretty simple to install. They keep a lot of water and air from entering the crawl space through the vents and also make it more difficult for animals and insects from making a home out of the crawl space. The humidity levels in a crawl space drop by an increased amount once the vents are covered up. They are especially useful in places like North Carolina, where flooding is frequent. 

However, vent covers will not stop wood rot. They may delay wood rotting, but it’s something you will have to deal with eventually if all you have set up are vent covers. Unencapsulated crawl spaces are still capable of getting flooded due to leaking, either from the pipes or from a plumbing issue within the house. 

  • What Truly Works to Deter Wood Rot  

So, if vent covers don’t work by themselves, what’s the solution? To truly keep your crawl space’s humidity levels acceptable, you will need to call an expert to fully waterproof your crawl space. This involves cleaning out and replacing any rotten wood from the crawl space, then insulation, encapsulation, and the installment of an interior drainage system, a sump pump, and a dehumidifier. All of this may sound overwhelming, but it is the only way to make sure your wooden support beams and concrete stay strong and sound. 

The insulation is meant for thermal control while the encapsulation is meant to keep the crawl space completely isolated from the outside world. Any water that comes through will be immediately intercepted by the interior drainage system and pumped out by the sump pump so it won’t be a problem. As for humidity, the dehumidifier is meant to keep the moisture levels low. 

Once you realize your wood is rotting, what can you do? You could always call a professional to assess the damage and see how salvageable the wood is, but if you aren’t able to call one right away and want to check the damage yourself, here’s what you need to look out for: 

  • Unsalvageable Wood Rot  

Unsalvageable wood rot cannot be cleaned, dried, or repaired. It’s the kind of rot that requires you to completely replace the wooden support. Usually, the kinds of fungus that cause the wood to be unusable are those that make the wood shrink and soften up. Once the wood’s internal structure has been debilitated so heavily, it will never be able to support the house’s weight the same way it used to. Even if you manage to eliminate the fungal growth, the wood is still smaller than it used to be and likely to snap under the weight of the house. 

Softwood rot needs to be removed and replaced as soon as you detect it because it’s the type of fungus that quickly spreads to other support beams. While you’re dealing with one part of the wood rot, the fungal growth will be spreading to other support beams. If you rely on clearing this kind of fungal growth on all the wood in your crawl space, the entire infrastructure will have been debilitated by the time you’re done. 

  • Salvageable Wood Rot  

If the wood hasn’t been softened up or shrunken down, it can be saved if the fungal growth isn’t too severe. However, the process of clearing wood from any fungal growth might be a little too difficult for the average homeowner, even those with a DIY background. To salvage the wood, it must first be dried out and the humidity levels in the crawl space need to be as low as possible. This cannot be done with a normal, household dehumidifier because they aren’t potent enough to properly dehumidify a moisture-filled area like a crawl space. An industry-grade dehumidifier is required. 

Next, either a fungicide or a wood preservative must be used to kill the fungus. This can be dangerous to handle because many of them contain harmful chemicals. The most effective fungicide products are only available to professionals, so most off-the-shelf products won’t get rid of the problem completely. Finally, a hardener is applied to strengthen the wood and fill any holes and cracks. Some hardeners are only to be used on door frames and wooden tables; these are not strong enough to help crawl space support beams hold up an entire house, so the hardener needs to be chosen carefully. 

If you’re aware that the moisture levels in your crawl space are too high, you might have a lot of questions. How soon will the wood begin to rot? How long can I wait until it becomes a big problem? As mentioned previously, wood rot is extremely difficult to take care of yourself. Not only is fungal growth hard to get rid of, but the products needed to do the job properly also aren’t always available. You will definitely need to call an expert eventually. 

But just because there’s moisture in your crawl space doesn’t mean that the wood will begin rotting immediately. So how will you know when it’s time to deal with the problem? 

  • If You’re Able to Access the Crawl Space  

The moment you notice spores or fungal growth anywhere in the crawl space (whether it’s on the wood or not), it’s time to deal with the problem. The fungus and mold can and will eventually transfer over the wood, so action must be taken before it happens. 

Some fungi can be very sneaky when it comes to rotting wood. The wood doesn’t always show discoloration, so what you can do is test your wood’s strength by using a screwdriver. Any kind of softness is indicative of fungal growth. Even if the wood looks fine otherwise, something needs to be done before the fungus spreads. 

  • If You’re Unable to Access the Crawl Space 

If you’re unable to check on the wood in your crawl space, look for problem signs elsewhere in your home. Mold on carpets, in the kitchen, and in bathrooms are usually a good indicator that the humidity levels are extremely high. Crawl spaces are usually a lot more humid than the rest of the house, so if things are moldy upstairs, the crawl space is probably in worse condition. 

The smell is another good indicator. Because of the stack effect, most of the air you breathe comes from the crawl space. If the fungal growth has gotten so intense that you can smell it, it’s time to call someone in for crawl space repairs. 

Call Tar Heel Basement Systems for Crawl Space Repairs 

There’s nothing more important than making sure your house is structurally sound. This is why you need experts who can provide the best solutions when it comes to repairing your crawl space. Tar Heel Basement Systems has been proud to serve Winston-Salem and Raleigh, NC, since 2003. We are always on hand to help homeowners feel like their houses are stable and secure. 

Contact us today to schedule a free crawl space inspection and repair quote. Once one of our experts assesses your crawl space, you’ll have a better idea of what you’re up against, what we can do to repair it, and how much the repairs will cost. Don’t hesitate; we can have your crawl space looking brand new in no time at all. 

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