Warning Signs: How to Tell If You Have Mold Behind the Walls


It’s the real-life monster that no one wants in their home. It’s the four-letter word that causes homeowners to scream in terror. It’s mold, and it’s a problem for many homeowners. For some people, indoor mold spores can cause symptoms ranging from sneezing and eye irritation to serious lung problems. The good news is that if detected early, mold can be safely removed before it becomes a catastrophe.

How do you know if it’s mold?

The bad news: Mold loves to hide. How do you find this evil house guest before it’s too late? Your nose knows.

Your sense of smell is the first line of defense against mold. You can often smell mold before you can see it. If you notice a musty smell in your home, there’s a good chance you have mold. If you think you have a mold problem, get on your hands and knees and smell the electrical outlets. As silly as it sounds, this is not a practical joke. Outlets have better access to the area behind walls, and smelling them can help pinpoint the mold problem. If mold is there, you’ll be able to smell it.

You should also investigate the areas in your home where mold loves to hide. Basements and bathrooms are likely places, but check out our infographic revealing the six secret places mold loves to hide: chimney, roof, windows, washing machines and under wallpaper.

If you’re still not sure, it’s time to call in a professional. Professionals can test the air for mold spores and determine if and exactly what type of mold is present.

Ready to get started on mold protection? Make sure you are doing it right.


Infographic: 6 Secret Place Mold Loves to Hide

So what do you do if you find mold?

If you do have mold, it’s important to tackle the problem quickly and safely.

Hire a professional to properly remove the mold and clean the area. Once you have ensured the source of moisture has been eliminated and everything is clean and dry, you can safely close up and refinish the affected area. When it comes to mold, too much precaution is just enough.

Of course, the best offense is a strong defense. Preventing the problem is key to a healthy home.  Keep your home well-ventilated and dry, and use mold resistant drywall and insulation.

Think it might be time to call in help? We maintain a database of professionals we trust and you can too.

 Link to CertainTeed's Find a Pro page

September is Mold Awareness Month. For more information on mold and mold removal, visit Mold: The Unwelcome Houseguest.



  1. I needed to leave a comment, man do I’ve a hard time writing
    a blog. Im endeavoring to kick start one on my website and I must
    its not easy at all. I really do admire people like yourself who are
    able to reveal anything with ease. Keep up the good work!

  2. Thanks for the recommendation about checking bathrooms and basements for mold. My mother’s house smells damp and musty, but I haven’t found any signs in any of the bathrooms. I forgot to check the basements, but I bet a mold removal service would find it down there.

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