Let’s talk about something most of us don’t think about until it’s a problem – mold popping up in closets packed with who-knows-what. I recently dealt with this firsthand and realized how easy it is for mold to sneak in and start growing quietly behind all that stored stuff. The problem is, closets are kind of perfect for mold, and you usually don’t notice it until it’s already made itself at home.
Mold doesn’t need much to get going – just a little moisture, something organic to feed on, and a lack of airflow. Closets tend to check all those boxes, especially if they’re jam-packed. Here’s how:
If mold is going to grow, it’ll usually start in spots that don’t get much attention – like:
It’s not always easy to spot mold right away, but here are some clues that might tip you off:
If you want to keep your closet mold-free, you’ve got to be a little proactive. Here’s what’s worked for me:
Once it was empty, I noticed a patch of mold tucked away in the back corner. I pulled back the carpet to get a better look—not terrible, but enough to raise a red flag. What really got me was when I popped off the baseboard and saw mold behind it, too. The baseboard itself and the drywall behind it were both contaminated. At least it hadn’t involved the sub floor material. That was a good sign I had caught it early.
Now, if you’ve spent any time around mold, you know the visible growth is just a symptom. The real issue is why it’s growing. I had to figure out where the moisture was coming from. On one side of the closet is the bathroom with a shower I installed myself – not a likely culprit. The other wall is an exterior wall, and there were no signs of water intrusion. My best guess? Condensation from a cold winter that settled into that corner.
The carpet was clean, and the subfloor looked fine – no signs of moisture damage there. Still, I needed to be sure. Time to bust out some tools. I used a moisture meter to test the wall – it was dry, readings were low, and the meter indicated the moisture in my dry hand was nearly triple of the wall. Then I grabbed my infrared camera. These things are great because they show temperature variations, which can point to cold spots and potential moisture issues.
The thermal image showed that corner was about 60 degrees, with a clear heat signature from the water heater on the other side of the wall. That red area showed heat coming through, but the corner itself was cold and dry—perfect conditions for condensation to form and mold to grow.
Zooming out, the door frame had another cold zone. Between the lack of airflow, the cold wall, and the stacked-up stuff, that mold never stood a chance of staying away.
This is an old house, with minimal insulation in the walls and single pane windows. We have to stay on top of keeping it high and dry.
I took some liquid detergent and a damp towel and I cleaned the spot.
Then I let it dry for two days.
Then I bought some paint and painted the corner. The guy at the paint store said he could match it better, but I said no, it’s good. It’s a closet.
The final step was to kick the carpet back in and call it good.
Closets can seem like a safe, out-of-sight spot to stash things, but they can also become mold havens if the conditions are right.
I have found mold in my own closets before. I used to live up near Bear Valley, California. My granddaughters loved to snow ski. They had their own bedroom in our house and used to stash their ski stuff in a closet. Damp, wet cold stuff. They packed it in good too. This was way back before I was a home inspector and didn’t know what I now know about mold. It took a bit more work to get that closet cleared out, but even then, I knew better than to use bleach or vinegar.
It is important that I express just how fast mold can creep in when the air is still, the walls are cold, and a few blankets or boxes can trap that moisture.
Regular check-ins, better airflow, and keeping things dry go a long way toward keeping mold out and your stuff in good shape!
Remember to also be aware of any changes to original construction like penetrations (e.g. phone lines, cable, gas, etc.) and structual differential settlement (i.e. roofs or walls moving and separating).
