How to get mold and mildew stains out of carpet

How to remove mildew and mold from carpet

1. 1

   Size it up and protect yourself

   Check how big the moldy area is and what caused it. If it's larger than about 10 square feet, came from sewage or flood water, or the padding is soaked, skip to the professional and replacement advice below. Otherwise put on rubber gloves, eye protection and an N-95 respirator, and open a window.

   Why: The EPA's mold guide suggests professional help for larger areas and contaminated water, and protective gear limits how many spores you breathe while you clean.

2. 2

   Test, then blot with dish-detergent solution

   Mix ¼ teaspoon of clear liquid dish soap in a cup of lukewarm water. Test it on a hidden patch of carpet, then apply it with a white cloth, working from the outer edge of the spot toward the center. Blot; don't scrub.

   Why: This is the Carpet and Rug Institute's first step for mildew. Mild detergent loosens the soil the fungus is growing on, and blotting from the edge in keeps it from spreading.

3. 3

   Follow with an ammonia solution

   If the stain remains, mix 1 tablespoon of household ammonia in a cup of water, test it on a hidden spot, and blot it on the same way. Use this on synthetic carpet only, not wool.

   Why: The ammonia solution is the Carpet and Rug Institute's next step for mildew. It's alkaline, which helps lift what the detergent leaves, but it can change some dyes and damages wool.

4. 4

   Rinse with plain water

   Mist or dab the spot with plain warm water and blot, repeating a few times.

   Why: Detergent or ammonia left in the pile stays sticky and attracts soil, so the spot turns dark again.

5. 5

   Dry the spot fast

   Blot until no more moisture comes up, then put a thick pad of white paper towels on the spot with a weight on top. Run fans and a dehumidifier until it's completely dry, within 24 to 48 hours.

   Why: Mold needs moisture. The EPA says drying wet materials within 24 to 48 hours usually stops mold from growing, and the weighted pad pulls up water before it wicks back.

6. 6

   Fix the moisture and check again

   Find the source: a leak, a damp slab, condensation, a potted plant, or high humidity. Keep indoor humidity at or below about 60 percent, and check the spot again over the next week.

   Why: Cleaning removes the growth you can see, but mold returns wherever the carpet stays damp.

What a mold stain on carpet actually is

Mold and mildew are fungi. On carpet, they feed on soil, spills and natural fibers whenever the pile, backing or pad stays damp. That makes it a biological stain: living growth plus the pigment it leaves. On fabric, Texas A&M notes that the color of a mildew stain is partly the shadow of tiny pits where the fungus has eaten into the fiber, so some discoloration can stay even after the mold is gone.

Carpet adds a problem fabric doesn't have: the backing and pad. You can only clean the top of the pile. If the stain came from water that soaked through, the mold you see may be the edge of growth underneath, which is why a musty smell after cleaning is a warning sign. The mildew smell guide covers the odor side.

When to clean and when to replace

Clean it yourself when the spot is small, on the surface, and came from a spill, a plant pot or a little condensation. Replace or call a professional when the carpet was soaked by a leak or flood, the area is larger than about 10 square feet, the water was contaminated, or someone in the home has asthma or other health concerns.

The EPA notes that porous materials like carpet may have to be thrown away if they get moldy, and Georgia's extension service says moldy padding should always be discarded. Carpet can often be saved if it's dried within 48 hours of getting wet.

By situation

Area rugs

Take a small rug outdoors before you clean it and shake or brush off loose growth there. Kentucky and Iowa State both say to brush mildew off outdoors so spores don't spread through the house. Then clean and dry it as above, flat or over a rail where air reaches both sides.

Carpet that got soaked by a leak or flood

Extract the water with a wet/dry vacuum, pull up and replace the saturated pad, and dry the carpet with fans and dehumidifiers within 24 to 48 hours. If mold has already grown on the pad, discard it. After contaminated flood water, professional cleaning or replacement is the safer choice.

A stain is left after the mold is gone

Georgia's extension guide suggests hydrogen peroxide for stubborn mold stains on carpet, after a test. Use 3% drugstore peroxide on a cloth and blot. It can lighten dyes, so test it on a hidden patch first. If the mark doesn't fade, it may be fiber damage.

Musty smell but no visible mold

Mold often hides under carpeting. Check the pad and the floor underneath at the edge of the room or near the smell. A professional can inspect if you can't find the source.

Wool carpet

Wool is a protein fiber and is damaged by alkalis and chlorine bleach, so skip the ammonia step. Use the dish-detergent solution sparingly and call a professional for anything more.

What not to do

• Don't brush or beat mildew off indoors. It sends spores into the air and spreads them to other damp spots.
• Don't pour chlorine bleach on carpet. Bleaching agents destroy carpet dyes and some fibers, and the EPA doesn't recommend bleach as a routine mold cleanup step. Removal and drying matter more.
• Don't mix ammonia with bleach. Together they release toxic chloramine gas.
• Don't soak the spot. Extra water reaches the backing and pad, slows drying and gives mold exactly what it needs to come back.
• Don't scrub. Scrubbing pushes the stain deeper and frays the pile into a fuzzy patch.

Other methods that work

Professional cleaning

Georgia's extension service recommends professional shampooing or sponge-cleaning with carpet cleaning products for moldy carpet, and restoration specialists for valuable rugs.

Caution: Hot-water extraction adds moisture, so make sure the carpet will be dried quickly afterward.

White vinegar

Vinegar is widely suggested for musty spots, but no extension stain guide recommends it for mildew stains. It's traditional, with weak evidence.

Caution: Never use it with chlorine bleach, and test it first.

Stain still there?

The mold came back within weeks

The carpet or pad is still getting damp. Find the moisture source, check the pad underneath, and lower the humidity. If the pad is moldy, replace it.

The spot turned darker after cleaning

Detergent residue is attracting soil. Rinse again with plain water, blotting between rinses, and dry it with a weighted pad of paper towels.

Safety

• Wear gloves, eye protection and an N-95 respirator when cleaning mold.
• Never mix chlorine bleach with ammonia or acids; ventilate the room.
• People with asthma, allergies or other breathing problems should leave mold cleanup to someone else.

Never mix cleaning products; see chemicals you must never combine.

Questions

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