Why Are My Wood Floors Turning Black?

Wood floors are a durable choice that not only look great, but are also designed to withstand the test of time.

However, if you’ve had your wood floors for a while you might be curious to know: Why are my wood floors turning black?

In this article, I will cover some important information about maintaining your wood floors, including why they might be turning black.

Keep reading to find out more.

While wood floors are designed to last, this doesn’t mean that they don’t need to be carefully looked after and require specific maintenance.

Why Are My Wood Floors Turning Black

What is Causing these dark marks?

Your wood floors could be turning black for a few reasons, one of which is mold. Mold grows where there is moisture, and black discoloration in your wood flooring can indicate both moisture and mold. That being said, if a significant amount of water spilled over your wood floors, then this could provide the perfect environment for mold to grow.

When the wood itself has turned black or is blackening, the discoloration could be a result of mold, or it may be down to the tannins in the wood reacting with the minerals in the water that has been spilled on the flooring.

It is important for you to know that there is a large distinction between black discoloration that is only on the surface of your wood flooring and in a discoloration of the wood itself. However, typically speaking you can attribute the problem to moisture in both cases.

In the first instance, getting rid of the discoloration is relatively simple. However, if the discoloration is due to the latter, there’s a lot more work involved in the remediation process. 

In both circumstances, whether it’s due to mold or tannins, the remedy involves stripping the finish and bleaching the wood to get rid of the affected area. If you just want to revive it, we go into details here.

What are the best solutions for this?

You can kill the mold and get rid of some of the discoloration using wood bleach, but you may have to stain and refinish part of your wood floor.

Kill the surface mold 

If your floor has started going moldy and turning black because it h as gotten wet, then to kill the mold you will first need to dry out the floor. You can achieve this through placing a big heater and fans in the room, as well as using your central heating to dry out the affected area. You will need to keep the room well ventilated as you do this, as any kind of moisture is what feeds the mold.

If mold is growing on the surface of the floor and it hasn’t penetrated the finish, you can kill it by washing with a solution of chlorine bleach and water. 

Sand and apply bleach to the affected area

The tricky thing about mold is that it grows when the conditions are right for it, even when you can’t see it. This means you often notice when it is too late, as it is likely that by the time you have noticed the wood blackening, the mold has usually penetrated into the wood.

After drying the floor, you will need to sand off the finish with a hand sander so you can apply wood bleach to the affected area. Apply chlorine bleach to kill mold, making sure to neutralize it with a solution of 1-cup baking soda per gallon of water before rinsing and drying the wood.

Stain and refinish the affected area 

Once you have finished bleaching the affected area, you will need to stain and refinish where you have treated the floor. This comes down to the fact that bleaching raises the wood grain and changes the color. 

You can find a stain that matches most floor colors, but if the match isn’t exact, then it’s better to opt for a lighter color than a darker one. Otherwise you’ll be left with the black patch that you’ve worked so hard to get rid of!

The main thing to remember is that you have to remain realistic. Repairs don’t always blend to match the floor exactly. If you want to ensure a seamless result, then sometimes the only way to hide a patch is to sand and refinish the entire floor as opposed to the specific black patch of wood. 

What role do tannins play?

Most tree and plant species contain tannin in varying levels and strengths. Tannins exist in many woods, most notably cedar and redwood. 

As a rule of thumb, the lighter-colored the wood, the lower the tannin content. Oak, walnut, cherry, and mahogany, have higher tannin levels, while maple and birch rank low in tannin content and acidity. To figure out the tannin content of your wood flooring, you will need to know what type of wood it is and do your research. 

Quite often, another reason that your floor can turn black is down to tannins. This is because tannins can bleed through to the surface, leaving a yellowish-brown stain on the surface. These stains are more noticeable on lighter paint colors.

That being said, if you notice your floor or parts of your wardrobe made with the same wood are turning a different color, it could be for this reason.

Is black mold on wood dangerous?

Yes, wood mold can cause allergic reactions in some people. Although mold may not be dangerous in itself, it may produce various toxins that fill the air. 

While it is rare to come across an aggressively toxic wood mold, it’s still not a nice reality to have in your home. As soon as you discover the mold problem, you should try to get rid of it.

In summary 

Your wood floors could be turning black for a variety of reasons, but it is likely a mold issue as a result of excess moisture. 

You will need to establish whether the mold is on the surface, or has discolored the wood itself and find a solution accordingly.