Mold Under Carpet: How to Know It's There

A musty smell is the most common clue. It tends to get stronger when the room is closed or humid. Another sign is dark spots or stains on the carpet surface, especially along baseboards or near walls. You might also see a faint gray or green tint in the fibers.

Press your hand or a dry cloth on the carpet. If it feels damp or leaves a wet mark, moisture is present. That moisture can feed mold even if you cannot see it. Also check the padding and the subfloor by lifting a corner, but do this only if you are comfortable and the area looks dry enough to handle.

• Musty or earthy odor that returns after cleaning
• Visible dark spots or streaks on carpet fibers
• Damp or cold feeling underfoot
• Warped baseboards or peeling paint near the floor
• Increased allergy symptoms like sneezing or itchy eyes
• Carpet that does not dry out within a day after spills

Start with your nose. Walk through the room and notice any musty smell, especially near baseboards or under furniture. Then use a flashlight to look for color changes or water stains on the carpet surface. Run your hand over the pile to feel for dampness or a slimy texture.

You can also place a clean, dry white cloth on the carpet and press down with a book. Leave it for a few hours. If the cloth comes up damp or stained, moisture is wicking up from below. That is a strong sign that mold may be growing underneath.

If you cannot find the source of moisture or the mold covers more than a few square feet, bring in local water damage pros. They have tools to measure moisture levels in the carpet, padding, and subfloor. They can also dry the structure properly and remove affected materials.

Act quickly because mold can spread within days. Check your insurance policy to see if mold damage is covered. Policies vary, and your insurer decides what is covered. Also, if anyone in your home feels unwell from the smell, see a doctor for advice.