Steam Carpet Cleaning Can Cause Mold

Steam cleaning carpet can cause mold growth below the carpet if done improperly. Carpet is actually the largest filter in your home. Being a soft, porous surface, its fibers collect airborne particles including mold spores. Simply opening a door or window invites mold spores into your home. If your carpet has been steam cleaned in the past, and it took more than two days to dry, you could have mold growth beneath it.

Officially known as Hot Water Extraction, but commonly called “steam carpet cleaning,” this method injects hot water into your fibers while simultaneously vacuuming it back out. Steam cleaning is actually misnomer, however. The ‘steam’ is really just hot water forced through high pressure jets appearing as steam in form, but not function. In an unregulated industry with a low barrier to entry, unscrupulous companies can leave you fibers too wet, which can create a hazardous indoor environment.

Mold spores are tiny seed-like pods that have one mission: seek and destroy! They waft through the air and hide in tight spots, like our carpet. As they lie dormant, they wait for the perfect conditions to start to grow. While EverClean, LLC is not certified as a mold expert, we understand that mold spores seek two things: moisture and organic material. When introduced to these two items, mold spores begin to break down the organic material, which can create a hazardous environment within your home.

Why Mold Can Grow Under Carpet

mold on wood subfloor

If a steam cleaner has left your carpet too wet, there is a potential for mold growth on the backing. Mold requires dark, moist areas that contain organic matter. Most of today’s carpeting contains synthetic materials; however, the backing contains latex glue, an organic food source. Most older rugs also have jute backing, another organic food source.

The latex glue within the primary backing can support mold, though a bigger concern is the pad and subfloor below. Carpet padding is made from the same sponge-like material you wash your car with. The pad can not only hold water for weeks, but months! Worse, it can transfer the moisture to the raw wood beneath it, a plentiful organic food source for mold.

How Carpet Mold Can Start

1. Wand Dragging

carpet cleaning vacuum wand

Searching “steam carpet cleaning 800 psi” on YouTube will show plenty of videos where cleaners over-wet their customer’s flooring. The first dangerous habit occurs when a cleaner drags his wand slowly across the floor. This injects more water than usual into the fibers for a deeper cleaning. However, the excess water is absorbed into the sponge-like pad beneath.

While the carpet cleaning wand is connected to a vacuum system, the excess water absorbs into the pad. While it may appear solid, carpet is actually a mesh, similar to a fishing net, so water passes right through it. This allows the pad to absorb excessive water.

Below the carpet is a dark environment. When wet for extended period of time, it can harbor mold and mildew. Plus, the dark environment blocks mold-killing Ultra Violets light. The carpet may appear clean and even feel dry after an excessive steam cleaning; however, if the pad and subfloor are wet, mold could follow.

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

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 cleaning companies 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 rugs may seem dry soon after, but the pad is likely still wet.

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

3. Choked Vacuum

carpet cleaning wand marks in carpet

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 fibers.

It is important that your cleaning company lifts the wand off the carpet in between strokes. Lifting the wand off the floor between wand strokes allows for stronger air flow and increased water lift. Once the wand is returned to the fibers, the vacuum removes more water as airflow builds. Keeping the wand on the fibers for long periods of time reduces airflow and extends dry time.

How to Reduce Carpet Mold

All cleaning companies want to deliver the best results for their customer. Many however apply too much water, which can lead to the pad getting wet and the potential of mold. It’s true that using more water gets the fibers 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 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 fibers and subfloor. If you suspect mold growth, have a professional environmentalist evaluate your carpet, pad and subfloor.

Steam Cleaning Alternatives

Dry Compound Cleaning

This cleaning method uses cellulose powder, a type of wood flour, to clean your fibers. A technician first pre-mists your fibers 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 fibers usually dry 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 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.

Dry Carpet Cleaning

dry carpet cleaning bonnet

Dry Carpet Cleaning, or Very Low Moisture, is a common method that uses a encapsulating detergent as the cleaner. The process involves pre-spraying the fibers with the special detergent that loosens the soils. The technician then uses dry pads to absorb soils and moisture into the pad. As the floor dries, the detergent encapsulates remaining soils and crystalizes to a powder. Dry vacuuming the floor removes the crystals that have trapped the soils. The fibers are dry 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 mold, though clean is relative to the detergent used.

SteamDry Carpet Cleaning

steamdry carpet cleaning in Nashville tn

Exclusively offered by EverClean, SteamDry combines the benefits of Hot Water Extraction with dry-pad absorption (VLM). SteamDry 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 fibers are moist, we scrub the them using dry pads to extract additional soils and moisture for clean, dry results. SteamDry delivers the most thorough results of the dry cleaning methods because it includes both hot water extraction and dry-pad absorption. SteamDry also eliminates the possibility of carpet mold because it dries in only a few hours.