Mold Removal & Mold Services - NJ Homeowner's Guide to Mold and Bleach

Mold spores are prevalent both inside and outside of man-made structures. In nature, mold plays an important role in the eco-system. Mold helps to break down carbon-based materials as part of nature’s recycling program. Although mold plays an important role in nature, when mold spores begin to grow inside a building there can be dire health consequences for people who come in contact with the mold spores. Therefore, the timely remediation of mold is important. In order to remove mold, many people turn to bleach. Recent research has shown that bleach may not be the best option for all mold situations.

What is bleach?

Bleach is a common household cleaner than has been used for many years to clean clothing as well as surfaces throughout the house. The first commercial application for the use of chlorine for bleaching came in 1785 by the French chemist Claude Berthollet. In 1799 the Scottish chemist Charles Macintosh invented the first modern chemical bleaching powder.

Most bleach today, that is mass produced for consumer use (such as bleach sold under the name of Clorox), has sodium hypochlorite as its main disinfecting ingredient. Sodium hypochlorite is derived from salt. In fact, many early productions of household bleach used ocean water as an ingredient. 

How do you use bleach to kill mold?

Bleach is used by many people to remediate mold. The most common way to use bleach in mold removal is to mix one cup of bleach with no less than one gallon of water and place the mixture in a spray bottle. Take a damp disposable towel and “pre-clean” the area that contains the mold. Once the area has been pre-cleaned, spray the bleach solution directly onto the area. Allow the bleach solution to sit on the area for at least five minutes. After five minutes has passed, the solution should be rinsed off with warm water.

Safety precautions must be adhered to when using bleach to remove mold. The act of scrubbing can release mold into the air. It is important not to ingest the mold particles. The EPA recommends anyone working near the mold to use at least a level N-95 respirator. It is also important to wear gloves that extend to at least the middle of the forearm. Eye protection is also very important and therefore, goggles should be worn at all times when working with mold. If possible, windows in the area should be opened to allow ventilation of the fumes from the bleach mixture. Lastly, since there is a great possibility that the bleach solution will drip, it is advised that the person remediating the mold wear work clothes that can be laundered immediately after the remediation is finished.

Even proponents of using bleach to remove mold will agree that the bleach solution will not be effective in many situations. The bleach solution is most effective on non-porous surfaces like countertops, glass, tiles, and bathtubs. Bleach solutions should not be used on porous materials like drywall and wood because it cannot completely kill mold. Due to bleach’s ability to remove color some people unfortunately believe that the mold has been removed because the stain is no longer there, however, the mold will reappear quickly since it was never really eradicated.

Is bleach safe to use?

Bleach is a product that is found in many homes and is used often as a cleaner. Although naturally occurring salt may be a main ingredient in bleach, that does not mean that exposure to sodium hypochlorite is completely safe. In fact, according to the Centers for Disease Control and Prevention (CDC) as well as the National Institute for Occupational Safety and Health (NIOSH), even short term exposure to sodium hypochlorite can cause an irritation to the eyes, skin, and respiratory tract. In fact, direct contact with high concentration of hypochlorite solutions can causes severe chemical burns which may lead to cell death and ulceration. 

 Is bleach effective against mold?

Bleach is a powerful oxidizer. In many cases bleach does an excellent job of sanitizing surfaces and removing certain types of bacteria. Bleach may remove mold from non-porous surfaces like glass or tile but in many cases it will actually only remove the discoloration caused by mold growth. People have observed that bleach may remove color but leave the microflora behind therefore enabling the mold to return in exactly the same spot when environmental conditions are right. Because bleach is so good at removing the discoloration, many people incorrectly believe that the mold itself is gone when simply the stain left by the mold is gone. 

In order to survive in harsh conditions, mold spreads its mycelia (roots) deep into porous surfaces. The active ingredients in common bleach make it difficult to soak into the material. In fact, many times the active ingredients stay on the surface but the water that is in the bleach solution is absorbed into the drywall or wood. Mold thrives on moisture so this process, although removing some mold from the surface, may actually be exacerbating the mold problem within the porous material. Due to this, it is not recommended to use bleach on porous materials. This can be a problem because mold is often found on drywall, wood, and other porous objects. If a person is using bleach to treat mold, the most common advice is to replace any porous surface that contains mold. Unfortunately, replacing large patches of drywall can be very expensive.

Are there alternatives to bleach?

When removing large areas of mold, especially from porous materials like drywall and wood, finding an alternative to bleach is a prudent move. There are antimicrobial products that have been created to kill mold on contact. If there is a large section of mold you need to remove, working with a professional mold remediator is often recommended as they will be able to recommend the antimicrobial that will work best in certain situations.