Making My House A Home

What Causes Black Spots On Hardwood Flooring?

by Bruce Burke

Big, black stains from pet urine is a common problem people encounter when they remove carpet and expose the flooring underneath. Knowing what causes this problem and what you can do about it can help you maintain your hardwood floors and can also help you take care of your home.

Why does pet urine stain hardwood flooring black?

When an animal, like a cat or a dog, pees on hardwood floor, a chemical reaction takes place between the ammonia in the urine and the tannins in the wood. This can cause the wood to stain to a very dark--or even black--color. Often pet urine is cleaned up quickly enough to prevent this chemical reaction from taking place, however, homeowners with carpet cannot prevent the urine from soaking into the hardwood floor beneath. This can cause black stains to build up on hardwood for a long time, creating layers of black stains.

What can you do about black spots on hardwood flooring?

If the hardwood flooring was originally stained a light color, like blond or ash, you can easily bleach the wood using hydrogen peroxide. Unless the stains are very deep, hydrogen peroxide will remove the damage. You can do this by following these steps:

  1. Fill a spray bottle with hydrogen peroxide.
  2. Spray a "test" area on the hardwood floor. To do this, spray your hardwood floor with one small spot of hydrogen peroxide.
  3. Wait one day.
  4. Check the area you sprayed with hydrogen peroxide to ensure that it has not reacted badly with the hardwood floor. If the area looks good, move on to the next step.
  5. Cover the dark areas of the hardwood floor with the hydrogen peroxide. Apply to the hardwood floor generously.
  6. Leave the hydrogen peroxide to sit on the stain overnight.
  7. Check the stain in the morning and repeat as necessary.

If the hardwood floor has a dark finish, using the hydrogen peroxide to bleach the stain will lighten the floorboard to a color much lighter than the finish around the stain. In addition, if the floors are stained blond but the stains themselves are too deep in the wood, the hydrogen peroxide might not fix the problem. In cases like this, you may have to completely refinish the hardwood floors.  

To find out more about refinishing your hardwood floors, or to get a quote for service, contact a reputable hardwood flooring contractor in your area. He or she can answer your questions and tell you whether or not refinishing is the right answer to your problem.

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