Black Stuff Under Carpet Pad? (Read This First)

By - Ron Singh

Updated -

Everyone wants to live in a clean environment with a pleasant smell. The cleanliness of your home environment boosts both physical and mental health.

Total cleanliness has to do with every home item correctly sought after. For example, your carpet is a prominent part of your house that needs proper maintenance.

You can’t just focus on the surface of the carpet and think it’s all in good shape. It is essential to check everything about it, especially the carpet pad.

Perhaps you recently noticed black stuff under your carpet pad, and it’s bothering you. In this article, we’ll discuss the black stuff under your carpet pad, how it got there and how to clean it.

The primary reason for the black stuff under your carpet pad is glue or rubber residue from previous carpet padding that has turned black. In other cases, it can be due to mold or mildew build-up because of a leak. The black stuff can also be a result of dust accumulation over time.

What Is the Black Stuff Under My Carpet?

Black Stuff Under Carpet Pad

Moisture is dangerous for your carpet. When your carpet gets wet, it becomes a suitable mold-growing environment.

It would help if you kept the carpet padding dry to prevent mold growth. Mold is one of the reasons for the black stuff under your carpet.

The mold gives an unappealing sight and unpleasant smell. Your carpet padding is excellent for absorbing and retaining moisture.

The carpet pad, in turn, becomes a favorable environment for mold to germinate, causing black stains. The moisture problem can be due to a leak under the padding.

Another reason for the black stuff under your carpet pad may be because of rubber and glue remnants from the previous carpet padding.

The staff from leftover glue or rubber pieces is usually complex and rubbery when touched.

 Removing the glue used for the previous one is mandatory when getting a new carpet pad. If you don’t remove this glue, it blackens after some time. 

Accumulating dirt and dust is another possible cause of black stains under your carpet pad. Carpets attract dirt and greasy residue; when this compounds after some time, it leaves a black mark. 

Black Powder Under Carpet Pad

Dust accumulation is the most likely source of black powder under your carpet pad. Carpet attracts dirt.

Thereby after a long time, this dirt builds up. If you don’t clean the dirt, it blackens and becomes a black powder under your carpet.

The latex glue adhesive used for making the carpet begins to break down after some time and turns powdery.

The powder falls to the floor, and when it stays there for a long time, it turns black. Another possible reason for the powder under your carpet is the carpet cleaner or deodorizer you’ve used.

When you use such cleaners, your vacuum must be able to erase it from the carpet completely.

If the machine isn’t powerful enough, powder particles accumulate beneath the padding and turn black if not cleaned up.

What Are Black Spots Under Carpet?

Finding black spots under your carpet isn’t a new or strange experience. However, there are various reasons why you’ll notice black spots under your carpet.

In addition, there are specific ways to identify these spots and the particular reason for each spot.

If you perceive an unsettling smell from the black spot under your carpet, then it’s probably mold.

Mildew or mold spots are a result of moisture build-up under your carpet. A humid sheen on them identifies these spots.

Another possible cause of the black spot under your carpet is the previous carpet’s rubber or glue residue.

These glue or rubber remnants become black after staying for an extended period. If you raise the spots with a rubbery texture, it’s glue residue.

The black spots can also be because of water stains after you’ve shampooed the carpet.

Is the Padding Under Carpet Toxic? 

The padding or underlayment is a cushion beneath your carpet to protect the hard flooring under it.

The padding also adds to the carpet’s thickness and convenience. In addition, the padding acts as a shock absorber for heavy furniture and foot traffic.

Most of you don’t know that carpet padding provides home insulation. However, carpet padding can be toxic depending on the material used in making it.

The padding gets made from foam, fiber, and rubber. The synthetic paddings are from nylon, polyester, and other chemicals that are usually toxic. Most paddings these days are made from polyurethane.

Although it is made from recycled waste and considered valuable, polyurethane contains harmful volatile organic compounds (VOCs). These VOCs are toxic and detrimental to human health.

 Rebounded recycled polyurethane makes bonded urethane, commonly called rebound. Rebond is an environmentally friendly material because it is recycled.

However, it contains a certain level of toxins. Most synthetic carpet paddings contain VOCs and other toxic chemicals that are dangerous.

Carpet paddings made from eco-friendly materials such as jute are non-toxic, except for those who are allergic to it.

Natural fibers such as jute, felt, animal hair, and others are the oldest types of materials used in making carpet pads.

These materials are eco-friendly and should be your best option considering allergies and safer living conditions. 

If there’s mold under your padding, it may be toxic, and you should treat it carefully. In addition, glue or rubber remnants from old carpets can also add to the toxicity of the padding.

Therefore, it’s essential to regularly clean underneath your carpet padding to avoid health risks.

How Do You Treat Black Stuff Under Carpet Pad?

The black stuff under your carpet padding should get cleaned once discovered. It is a common issue that you can treat quite quickly.

There are different causes of the black spot under your carpet, and you must treat it accordingly.

 Finding the exact cause of the black stain under your carpet pad is the first step in cleaning it. The two primary causes of the black spot are mold/mildew or leftover rubber from the previous padding.

Table Showing Steps to Remove Mold And Glue Residue From Under Carpet Pad

Mold/Mildew Glue/Rubber Residue
Put on protective clothing like gloves, masks, and safety glasses.Wear gloves, protective glasses, and other required safety materials.
Raise your carpet padding and confirm if it is mold growth.Take your time and inspect the area the black stuff has covered.
Use a stiff, firm brush to remove the mold gently.Use a good scrapper and clean the rubber residue. Be careful not to damage the floor.
Apply diluted bleach to the spot and let it rest for 15 minutes.Use an enzymatic cleaning product (mineral spirit) to clean out the remaining glue.
Clean the spot with a wet rag and dry the area. Use a steam cleaner to dry it; it helps in killing mold.You can also use sandpaper if the stains cover a wide area and you intend on refinishing the floor.
Ensure the area’s completely dry, then search for the leak or source of moisture. Fix this to prevent further mold growth.Use a vacuum to clean up the glue remnant or sweep it away.
You can use sandpaper if the mold covers a wide area. You’ll have to refinish the wood flooring after sanding it.A vacuum with a HEPA filter is the best option for you.

Please note that this cleaning method is more suitable if the black stuff covers just a tiny area.

However, if the stuff covers a broader area, it’s best to get help from a professional cleaning service.


Cleaning your carpet and beneath the padding should be part of your cleaning routine. Letting black stuff under the carpet pad accumulate is detrimental to health.

Mold or glue residue removal is simple. If you’re too busy or the stain is too much for you to handle, then employ the services of a cleaning agency.

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