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3 Reasons Why You Should Never Use Bleach To Clean Mold

Bleach is NOT the answer for many mold issues.

Chlorine bleach is often regarded as the answer for removing and halting mold growth. It is usually the first thing many reach for when cleaning a mold contaminated area. While bleach may be effective in certain applications, it will not exonerate mold on a porous surface. Bleach can actually contribute negatively to certain mold problems.

Bleach loses effectiveness over time.

Chlorine bleach rapidly looses its effectiveness. If you leave a glass of chlorinated water out on the counter for a few days, the chlorine will evaporate. This happens within the container as well. This evaporation process indicates that it will be hard to ascertain the true potency of your chlorine bleach solution, as the chlorine can escape through plastic. It may have been sitting at the store, or in your home for some time, diminishing the ability to perform.

Bleach does not kill mold on porous surfaces and can actually contribute to mold growth.

Chlorine bleach can only kill surface mold. Because mold can grow deep roots within porous surfaces such as wood and drywall, bleach will not assist you in exterminating mold. The chlorine cannot penetrate to destroy the growth at its roots; it remains on the surface while the water component of the bleach reaches further, which can actually feed the mold growth.

Bleach is toxic.

Chlorine bleach produces fumes that pollute the air and can become harmful to humans and pets. Chlorine bleach also generates a by-product called dioxin, which is linked to cancer. Use over time builds up these pollutants in the environment.

What should you use to kill mold?

If you have ascertained that it is safe to clean up the mold, there are a variety of options available. The most important step is to determine the cause of the moisture and make any necessary changes to assure that mold will not return and the area is properly ventilated. Some issues will need to be resolved by cutting out the moldy material and completely replacing it. This will make certain that the mold roots are removed and will not return.

Some people use vinegar, borax, hydrogen peroxide, tea tree oil or ammonia to kill mold, especially on small areas and non porous surfaces, as well as sanitizing mold and mildew on clothing. More specific biocides may be needed if you are dealing with a porous surface that you cannot remove, such as wood framing.

Safety First

Proper treatment for mold growth will depend on the surface it has populated. Always consult a professional before attempting to remediate a mold problem yourself. If you don’t have experience with mold remediation the EPA recommends that any mold problem larger than 10 square feet be examined by an expert.

Brian and Krystle Reeves manage MoldBlogger.com, a website dedicated to providing a place to share and receive information that will better allow individuals to fight and conquer toxic mold and the consequences of mold exposure.

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27 thoughts on “3 Reasons Why You Should Never Use Bleach To Clean Mold

  1. Thank you so much for this! We’ve always used bleach for mold clean-ups and this is very good information to have! We will have to be more careful from now on.

  2. We tried using bleach on sub flooring and drywall in a fixer to kill mold and it never worked. We had to cut it out completely and replace.

  3. Our daughter was planning to use a basement room for her adult daughters bedroom but discovered mold.She is on limited income and believes she can remove the mold herself. Are there any organizations who could help her achieve this at a greatly reduced cost so the space could safely be used in the basement

  4. I just set off 3 Mold Bombs..I was treating with bleach and though it seemed to work before my eyes..it kept returning in small spots..was wondering if I should spray or paint the wood beams in crawlspace as well?

  5. What happens if I thought I got rid of all the mold and take care of repairs only to have the mold come back where I can’t see? Will it destroy the home? Will it be unhealthy to live in?

  6. I have a tenant moving in and there is mold on much of his furniture including his mattress. He’s cleaning thnigs off with a bleach and water solution. How can I convince him that he needs to replace this stuff? How do I show him that he is contaminating a previously non-mold environment?

  7. MOST IF NOT ALL MOLD CONTAMINATION ISSUES
    DWELL STRONGLY AROUND UNCORRECTED ENVIRONMENTAL FACTORS, TEMPERATURE FLUCTUATIONS,WATER AND OR MOISTURE ISSUES,
    AIR FLOW AND NOT TO FORGET – THE LACK OF PREVENTIVE MAINTENANCE.A LITTLE SMART PREVENTIVE MAINTENANCE TODAY WILL SAVE THE CHECK BOOK PLENTY.

  8. I have been given a building that it would cost me 12 to $15,000 to build , I have seen obvious signs of mold on a wall . Built as a one room 30′ x 30 ‘ room ,recently added wall through center ,being on a low set income retirement ,it is tough to think of scrapping a perfectly great shop building ,which otherwise I can’t afford to build ,and will never be able to have one ,so if anyone can advise me on this only two year old structure ,it will be greatly appreciated . Thanks , TIM

  9. GREETINGS,
    BLEACH AND MOLD REMEDIATION.
    LOTS OF TALK ABOUT WHAT IS BEST FOR MOLD REMEDIATION PRACTICES.
    A POINT TO REMEMBER IS THAT ALMOST ALL FUNGICIDES AND OR ALGAECIDE CHEMICALS ARE WATER BASED OR REQUIRE WATER ADDITION FOR DILUTION.6%+BLEACH IS THE ALL AROUND DISINFECTANT FOR THE CRAWLSPACE JOB. KILLS, CLEANS, SANITIZES! THE TRICK IS THAT IF THE EXISTING CONTAMINATION LEVEL IS OUTRAGEOUS STRUCTURE REPLACEMENT IS DEEMED NECESSARY. BLEACH REQUIRES ADEQUATE FORCED VENTILATION [FANS]. ALWAYS TAKE CAUTION WHEN USING ANY BLEACHING AGENT WITHIN A CONFINED SPACE…!

  10. How do I get all of the mold spores out of the air after I removed the source? Also does anyone know what I can use on my cat’s mold rash that is safe and natural? Your help would be greatly appreciated. Thank you.

  11. When killing mold on porous surfaces like drywall and wood, I use Concrobium at Lowes, there are other out there as well. This usually does not remove the discoloration, it not designed for that, because of it’s non-toxic nature. I use it on the job when I see mold. Get it nice and damp, not to wet and it should be go to go. If you need to get rid of discoloration and your not painting, you could try bleach after the mold killer has all dried, then reapply mold killer after wards

  12. Sorry, forgot the the number 1 step. Correct the moisture problem 1st, otherwise this is all temporary.

  13. So true. Moisture is the culprit. Any attempts of cleaning mold without addressing moisture and leak issues will not be successful long-term.

  14. CONCROBIUM IS A GOOD PRODUCT FOR BATHROOM ALGAE REMOVER. NOT STRONG ENOUGH TO ACTUALLY KILL CONTAMINATION.SHEETROCK CONTAMINATION RULE OF THUMB… CUT IT OUT, CHEMICAL TREAT AREA [CHECK INSULATION CONDITION], REPLACE INFECTED MATERIAL.DO NOT CUT CORNERS WHEN ADDRESSING INTERIOR CONTAMINATION.!!
    RE-OCCURRENCE CAN CAUSE MAJOR PROBLEMS.!!

  15. I am a little confused by the title of this article “3 Reasons Why You Should Never Use Bleach To Clean Mold”- “20 thoughts on 3 Reasons Why You Should Never Use Bleach To Clean Mold”. The article breaks down different reasons why Bleach is toxic and overall, ineffective at permanently eliminating mold. Along, with the complexities- involving size of space with mold contamination and the type of material contaminated (from porous services, paper,wood, fabric, drywall, etc), making Bleach a dangerous, unreliable, mainly ineffective substance to combat mold; yet, people’s responses often talk about using bleach, either conveying it as a viable option and/or flat out suggesting the use of bleach in particular circumstances. The comments come across as if people have completely ignored the article’s professional advice. I am confused. After reading this article about why Bleach should not be used to eliminate mold (one of numerous articles I have read that reinforce the same advice), I am walking away with the understanding that bleach is not a wise approach when attempting to remove mold- DIY. I personally wouldn’t play around trying to eliminate mold, as a lay person. Mold and its spores attach to one’s clothes, are inhaled, and if the contamination is considered large enough- Professional Remediation is the recommendation, and certified companies must follow strict guidelines for mold removal. People who think DIY- I would think it’s important to know what amount is considered large, regarding mold contamination. Don’t assume safety or diminish the possibility one’s mold problem could be serious or dangerous, (to do DIY). I am not a person who fuels scares about mold, or whatever theories exist about Black Mold. I just think mold is not something to blow off, perceived as “just a mildew-type thing”, not dangerous, etc. My belief is that one address mold contamination, of any size, with research, and safety in mind.

  16. I am working on a job where the gutter down pipe ended right next to an outside corner and water found its way into walls through the siding. I pulled siding and found a mix of black and a ring of live spores embedded into drywall. KT covered about 15 s.f. so what I did was cut out drywall And used HEPA filter vac to clean up. And then I use vinager to clean all areas that were in with mold then spray peroxside on all and let air dry 24 hrs then rebuild

  17. I use trisodium phosphate & distilled water, then bleach and distilled water, more phosphate, acetic acid (vinegar), then I run over the whole thing with borax, or Boraguard termite & mold inhibiting treatment, then a borate/borax infused paint product specifically made for mold treatment. I have hot and cold foggers that will saturate an area with a alkali fog of borax or borate compound in water vapor or steam. I have used pelletized dry ice to remove the mold itself. That procedure is similar to sand blasting, but the dry ice is solid CO2 which is sublimated so it goes straight from pellets to a gas, and the sand, so to speak, just evaporates away. After that you really really need to run over everything with a borate mold inhibiting paint, or wood treatment. Citrus terpenes work well too. These would be orange peel oil, or lemon peel oil. You may not want to use these on woods you might want to stain or paint in the future.

  18. Just using the chlorine bleach is not a solution you can use other natural ways to remove black mold which definitely stop the growth of toxic black mold otherwise that black mold will reappear again and again. You can use tree oil, grapefruit, vinegar, baking soda etc which is a natural remedies and prevent black mold. You cna just go through these simple steps to clean Toxic black mold. http://www.floodaz.com/how-to-kill-black-mold/

  19. Any thoughts on my shoe closet where the shoes repeatedly grow small gray spots I presume are mold? Would placing a closet fan help with circulation as I keep my windows open all the time but live near the beach in San Diego.

  20. So instead of spraying a little bleach and rubbing, I should remove my entire back door, replace it and just hope the mold stays away?

    This is interesting advice.

  21. I did a lot of research on this, and the one thing I found out. Mold likes the same conditions we do. It needs organic food (like drywall, wood, etc), It needs water (high humidity usually), and a temperatures between 40 and 120 degrees F, tho it can survive lower and higher temps (but not below freezing for long, and generally not above 160 F) Removing the water is the best solution in most cases. Then use one of those products like Concrobium. But remember, it has a survival instinct. As soon as it is threatened by any kind of contact it releases spores. This includes spraying it with bleach. The only way I know of to slow that down is put a tent over the infested area and vacuum out the air through a filter to outdoors. There are over 5000 species of mold, 70+ of “black” mold. Some of these are linked to respiratory problems.

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