Steam Carpet Cleaning can Cause Mold Growth in Your Home

Carpet is the largest filter in your home. Being a soft, porous surface, carpet fibers collect airborne particles including mold spores. Simply opening a door or window invites mold spores into your home. Having your carpet steam cleaned can activate mold spores hiding deep in your carpet causing a potentially hazardous environment.

Officially known as Hot Water Extraction, but commonly called “steam carpet cleaning,” this method injects hot water into your carpet while simultaneously vacuuming it out. Steam cleaning is actually misnomer, however. The ‘steam’ is actually just hot water forced through high pressure jets to appear as steam. In an unregulated industry with low barrier to entry, steam cleaners can easily create mold in your carpet and home.

Mold Spores Everywhere

These tiny seed-like pods have one mission: Seek and Destroy! They waft through the air and hide in tight spots, like our carpet. They wait for the perfect conditions to start to grow. While we are not mold experts, we understand that mold spores seek moisture and organic material. When introduced to these two factors, mold spores begin to consume organic material. They then release more spores creating a potentially harmful indoor environment.

Why Mold Grows on Carpet

If a steam cleaner has left your carpet too wet, it has a good potential for mold growth. Mold needs dark, moist areas that contain organic matter, which a wet floor has. Most of today’s carpet contains synthetic materials. The backing however contains latex glue, an organic food-source. Most older carpets also have jute backing, another organic food source.

The latex glue within carpet backing can support mold growth. A larger concern however is the carpet pad and subfloor below it. Carpet pad contains the same sponge-like material you wash your car with. Carpet pad can actually hold water for weeks if not months! Worse, the wet carpet pad sits on top of raw wood, a plentiful food-source for mold!

Three Dangerous Steam Cleaning Habits to Look Out For

Danger #1: Dragging the Wand

Searching “steam carpet cleaning” on YouTube will show plenty of videos where cleaners over-wet their customer’s carpet. The first dangerous habit occurs when a carpet cleaner drags his wand slowly across the carpet. This injects a lot more water into the carpet for a deeper cleaning. However, the excess water is likely absorbing into the sponge-like pad beneath! The wand is connected to a vacuum system; however, the excess water does not always get vacuumed out. Carpet backing is a mesh, similar to a fishing net, so water passes right through it. This can give mold spores the chance to grow.

The carpet backing and wood subfloors commonly harbor mold when present. Plus, the dark environment under your carpet blocks mold-killing Ultra Violets light. This creates the perfect environment for mold to grow. The carpet may look very clean after an excessive steam cleaning, but mold that could soon follow.

Many carpet cleaners drag the wand to skip manually scrubbing the carpet. Thoroughly agitating the carpet fibers after applying detergent requires less water pressure, and water. But because dragging the wand requires less effort than manually scrubbing the carpet, it is often skipped unfortunately.

Danger #2: Excessive Water Pressure

Another mold-causing habit is turning the water pressure up higher than the 400 pounds per square inch (PSI) industry standard. Many carpet cleaners on YouTube that recommend an 800+ PSI, which is entirely too much water pressure. Considering the sponge-like pad just beneath those fibers, excessive water pressure can wet that pad for weeks! Even with high water pressure, the carpet may seem dry soon after, but the pad is likely still wet.

Similar to the air-cooling fins on a motorcycle engine, carpet fibers dry in a similar way through evaporation. This means the carpet will dry faster than the pad and subfloor beneath. If flooring is wet for more than two days, carpet mold can occur.

Danger #3: Choked Vacuum

Along with the first bad habit, many steam cleaners leave V-shaped lines in the carpet. This offers appeal while letting the customer know that the area has been cleaned. Leaving the wand on the carpet for extended periods of time creates a closed vacuum circuit. This reduces sufficient air flow and water delivery back to the vacuum waste tank. By not lifting the wand periodically, the technician reduces water lift and leaves excess water in the carpet.

It is important that your carpet cleaner lifts the wand off the carpet almost continually. Lifting the wand off the carpet between wand strokes allows for stronger air flow and increased water extraction. Once the wand is returned to the carpet pile, the vacuum removes more water as airflow builds. Keeping the wand on the carpet for long periods of time reduces airflow and extends dry time.

How to Reduce Carpet Mold

All carpet cleaners want to deliver great results for customer satisfaction. Unfortunately, many apply too much water, which can lead to carpet mold. It’s true that using more water gets the carpet cleaner, but at a potentially heavy cost to your health and pocket book. Unfortunately, replacing carpet that contains mold is the only option. Salvaging carpet after mold is impossible as it is too porous for complete removal.

When contracting with a professional carpet cleaning company, we recommend you request the water pressure to remain under 400 PSI. We also recommend having the technician move the wand at about the pace of walking. And our third recommendation is to have them lift the wand off the carpet each time they move the wand to a new stroke position. This will greatly reduce the possibility of over-wetting your carpet. If you suspect mold under your carpet, have a professional environmentalist evaluate your carpet.

Steam Cleaning Alternatives

Dry Compound Cleaning

This carpet cleaning method uses cellulose powder, a type of wood flour, to clean your carpet fibers. A technician first pre-mists your carpet then brushes in the cellulose powder. The powder acts like tiny sponges that absorb the soils quite well. The carpet is then vacuumed thoroughly extracting out the powder with the soils attached to them. The carpet usually dries within an hour of pre-misting, so the chance of mold growth is unlikely.

Dry Compound Cleaning can include carcinogenic solvents within the cellulose to allow for better cleanability. It is best to ask the carpet cleaning company to provide you with a Safety Data Sheet (SDS). This informational sheet allows you to see what the cellulose powder contains prior to use.

Very Low Moisture (VLM)

Very Low Moisture is a common dry carpet cleaning method that uses a encapsulating detergent as the cleaner. The process involves pre-spraying the carpet with the special detergent that loosens the soils. The technician then uses dry pads to absorb soils and moisture into the pad. As the carpet dries, the detergent encapsulates remaining soils and crystalizes to a powder. Dry vacuuming the carpet removes the crystals that have trapped the soils. The carpet dries in only a few hours.

The Very Low Moisture method is somewhat controversial as the encapsulating detergents differ greatly in their effectiveness. I have seen some encapsulating detergents that leave a sticky, soil trapping residue. However, I have also seen other detergents that dry to a brittle crystal. The brittle crystal traps the soils and allows the method to work correctly. Overall, VLM eliminates the possibility of carpet mold, though clean is relative to the detergent used.

SteemDry (Wet-Dry Extraction)

Exclusively offered by EverClean Carpet Cleaning of Nashville, TN, SteemDry combines the benefits of Hot Water Extraction with dry-pad absorption (VLM). SteemDry delivers deep cleaning results with only a few hours dry time because it uses up to 70% less water than traditional steam carpet cleaning!

Our technicians first apply hot water containing soap-free, nontoxic detergent to loosen soils before extracting it out with powerful vacuums. While the carpet is moist, we scrub the carpet fibers clean using dry pads to extract additional soils and moisture for clean, dry results. SteemDry delivers the most thorough results of the dry cleaning methods because it includes both hot water extraction and dry-pad absorption. SteemDry also eliminates the possibility of carpet mold because the carpet dries in only a few hours.