How We Got Rid of Mold in Bathroom Cabinet (Step By Step)

If you have mold in bathroom cabinets, you’ll find this guide helpful.

Mold occurs naturally and can grow on any surface. It thrives in mold-friendly environments, such as damp and humid spaces.

Your bathroom cabinets are a perfect breeding ground for mold because they often contain moisture from things like sponges or wet towels.

Also, bathrooms can be one of the most humid places in your home during and after taking a shower.

This is compounded when your bathroom doesn’t have an exhaust fan or windows to effectively remove the hot humid produced when showering.

In this guide, we will review a case involving mold growth caused by high humidity. We will the steps that were taken to resolve this condition and prevent mold regrowth.

Uncovering The Mold in Bathroom Cabinet

In this case, the homeowner kept smelling musty odors every time they opened the lower cabinet in the bathroom.

The smell was stronger in the cabinets directly under the sink location.

They mentioned that it had been an ongoing issue for several weeks. They kept cleaning the bathroom areas with bleach and other cleaning solutions, but she was still unable to get rid of the smell.

When the bathroom was inspected, we noticed that there were no signs of water damage, but we could smell a strong, musty odor – like wet clothes that have been stored in a dirty hamper for days.

Upon closer observation, we noticed that there was some suspected fungal growth (possibly mold) around the drain lines for the vanity.

In most cases this is an indication that there is some issue between the wall and the back of the vanity.

A small section of the vanity was pulled from the wall and we observed mold growth on the back of the cabinet.

We recommended the removal of both bath vanities to find the leak and remediate the affected areas. The steps below were taken to help the homeowner address the condition in their home.

Here’s What We Found

Upon closer observation, we were unable to locate any leaks when the vanity was removed. However, we observed a significant amount of mold growth on the wall and the back of the cabinet/vanity.

The issue here was that the openings around the drain lines were not sealed to prevent hot air from collecting between the wall and the back of the cabinet.

This hot air would meet cold surfaces which in turn creates condensation. 

Steps We Took To Get Rid Of The Mold Growth in Bathroom Cabinet

Containment was set up in the area to protect occupants from any potential mold exposure.

The contained areas were placed under negative pressure that exhaust to the exterior of the home.

This process allows the air scrubber to collect the spores in the HEPA filter and exhaust the filtered air outdoors.

The affected vanity and countertop were removed. We noticed that one vanity was severely damaged and needed to be discarded.

The other vanity had minimal growth and could be salvaged

The cabinets were wrapped in 6 mil poly sheeting and removed from the home. One section was discarded, and the other was taken to be treated and sealed to prevent any regrowth

1. Removed vanities and the countertop affected by microbial growth.
2. HEPA Vacuum the wall and surrounding areas
3. Treated the area with Benefect Decon 30.
4. Installed air mover to aid in drying out the area.
5. Sealed the area around the drain lines that caused hot air to seep between the wall and the back of the vanity
6. Final cleaning of work area includes wiping down solid surfaces, HEPA vacuum floors, and carpet.

The vanity that was salvaged was treated by the following methods:

1. HEPA vacuuming the affected surfaces.
2. Used Benefect Decon to clean and sanitize the affected surfaces.
3. We placed the vanity outdoors to expedite the dry-out process.
4. Moisture readings were taken to verify the materials were dry.
5. The surfaces were sanded to remove any discoloration and rough-edges.
6. A moisture sealant “SPAR URETHANE” was applied to seal all the surfaces at the back of the vanity- this will prevent any moisture wicking into the material. Two coats were applied, as suggested by the manufacturer.
7. The material was allowed to dry over the weekend.

Final Thoughts

As you can see from this case, mold can grow as long as it can find a moisture source. 

Moisture sources in your bathroom can come from leaks, spills, leaving wet clothing in bathrooms areas for long periods, and from high relative humidity.   

The relative humidity according to ASHARE should be between 30-60%.

When humidity levels become higher, mold growth can and will occur. Therefore, its important to make sure you run your bathroom exhaust fan while showering and for about 30 minutes after. 

Taking this simple step can help to remove the hot humid air that accumulated in the bathroom while showering.