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5 Levels of Mold Remediation

by Joslyn
Moldy Ceiling

What are the 5 levels of Mold Remediation?

According to Vicki Lankarge in her book “What Every Home Owner Needs to Know About Mold & What to Do About It,” mold remediation can be broken up into 5 levels: level one being the least contamination, level four being the most, and level five HVAC and air conditioning systems.

When dealing with mold contamination in your home it can be difficult to decide when a mold remediator is needed or what you can take care of yourself.

In the following 5 levels, you will have a guideline to go by when removing mold from your home :

5 Levels of Mold Remediation

  • Level I (10 square feet or less)

Smaller infestations categorized in level I is mostly found on ceilings or baseboards. Level I mold contamination may be cleaned without hiring a mold remediator, but there are several important safety precautions that you need to know :

1. Do not attempt cleaning mold if you suffer from asthma, allergies, or immune disorders

2. Wear gloves, eye protection, and an N95 disposable respirator

3. Vacate from your work area any infants less than 12 months old, individuals recovering from recent surgery, anyone with a suppressed immune system, or people with chronic lung diseases such as asthma, sever allergies, emphysema, etc.

4. Contaminated materials that cannot be cleaned should be removed from your home in a sealed plastic bag to prevent an infestation in another part of your home.

5. Clean your work area when you’re done with a damp cloth or mop.

6. Make sure all areas are left dry and visibly free of mold contamination.

  • Level II (10-30 square feet)

To remove mold from an area category the size of level II (probably one wall panel), the same precautions used in level I should be taken as well as the following :

1. Moldy materials should be covered with plastic sheets and sealed with tape before any handling or removal of materials. This will contain dust and debris. It may be wise to double wrap in plastic before escorting the moldy material from your home.

2. WHen the mold removal is finished, vacuum the work area with a HEPA vacujum. Clean the area with a damp cloth or mop.

  • Level III (30-100 square feet)

Mold contamination this size (patches of mold on several wall panels), should still be handled with the same precautions as level I and II as well as the following added measures :

1. Seal ventilation ducts/grills in the work area and areas directly adjacent with plastic sheeting.

2. Vacate everyone from your work area until work is completed. Further vacate adjacent work areas of any infants less than 12 months old, individuals recovering from recent surgery, anyone with a suppressed immune system, or people with chronic lung diseases such as astma, sever allergies, emphysema, etc.

  • Level IV (greater than 100 square feet)

An infestation depending on how much greater than 100 square feet may require the assistance of a mold remediator. If not, the same requirements should be followed as were needed in levels I, II, and III along with the following :

1. Every worker must be trained in the handling of hazardous materials and equipped with full face respirators with high-efficiency particulate air (HEPA) cartridges, with disposable protective clothing covering both head and shoes.

2. Make sure workers completely isolate hteir work area from the rest of your home with sheeting sealed with duct tape, including ventilation ducts/grills, fixtures, and any other openings.

3. Make sure workers set up and use a “decontamination room,” or a chamber taped off with plastic sheeting. The outside of sealed bags containing contaminated material should be wiped down with a damp cloth or HEPA vacuumed in the decontamination chamber prior to their removal.

4. Air monitoring should be conducted prior to moving back into your home to determine if it is fit to reoccupy.

  • Level V (Air Conditioners and HVAC Systems)

If there is a small area of mold growth beneath your air conditioning system it would be safe to apply precautions from levels I and II to remediate the mold contamination. However, all remediation procedures for air conditioning units and HVAC systems should be left to professionals. Procedures for level V remediation for areas larger than 10 square feet are the same for all previous levels with the following precautionary measures added :

1. Shut down the HVAC system prior to remediation.

2. Growth-supporting materials that are contaminated, such as the patper on the insulation of interior lined ducts and filters, should be removed and sealed in plastic bags.

3. A variety of biocides – broad spectrum antimicrobial agents designed to prevent the growth of microorganisms – are recommended by HVAC manufacturers for use with HVAC components, such as cooling coils and condensation pans. HVAC manufacturers should be consulted for the prodcuts they recommend for use in their systems.

Further Recommended Reading :

Joslyn from the MoldBlogger team

Source: Lankarge, Vicki. “What Every Home Owner Needs to Know About Mold & What to Do About It.” 52-58.

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Dan Madison April 9, 2008 - 9:15 am

Great information. As you can see, several precautions should be taken when handling mold. I’ve discovered it is easy to aggrevate mold and end up spreading the spores to another part of the house. We had a fairly low level of mold and hired EcoGuard Mold Solutions and they did a great job masking off the infected area and keeping the rest of our house safe. http://www.ecoguardsolutions.com

Bill Gregory May 26, 2008 - 4:42 pm

Really great info and blog! Mold damage and removal can be a serious problem. Negative air containment is very important during remediation. For professional mold abatement in Orange County California visit http://www.gregoryrestoration.com

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Sherry Sloan March 26, 2009 - 7:38 am

Help! We smell mildew but we can’t find it. All five of us agree the smell is in one area but we have checked the floor, rugs, wall, cabinets, closets, furniture, even the attic in that area and still no visible mold or mildew.

Mold Removal Tampa March 7, 2010 - 3:16 pm

This is great info relating to mold damage remediation.. We completely agree with Bill above that neg. air containment is very important to prevent the further growth and migration of mold spores.

Mold Killer Carol August 13, 2010 - 2:21 pm

It is interesting how mold can grow very fast and spread in a home. Definitely not good for your health! So to just leave it and do nothing is a ticking time bomb. Mold remediation is costly but well worth it if you have an infestation of mold that needs to be taken care of. A mold specialist can get to the source of the problem and get rid of the mold so it won’t come back.

Water Damage Lincoln Nebraska June 17, 2011 - 10:28 am

This does a pretty good job of laying out the spectrum of mold infestation.

For instance, if you find a small spot of mold, it may not require a pro. Very good common sense information on moldblogger!

David September 26, 2011 - 8:44 pm

So after 10 months of owning our home, we have found that we have the Black Toxic mold Stachybotrys_chartarum behind our kitchen cabinets and apparently they have been found at different places in the carpet. While we are dealing with a professional contractor to deal with the situation and have had to move out of the house, we are receiving different stories about what items in the home need to be removed and disposed. For example, we were told to dispose of anything plastic, like dishes, toys… But my TV is plastic? And so is my computer? What is the truth… I don’t want to trash a perfectly good computer if I don’t have too. So far it seems like no one is really sure or they don’t want to dissapoint me.

Mold Tampa October 11, 2011 - 12:12 am


Anything that is hard plastic or glass can be cleaned from mold with a solution as simple as soap and water. Once mold gets into carpet, or upholestry it must be cleaned by a professional in order to completely remove it. Any hard surface items do not need to be thrown out, simply cleaned. Hope his helps!

Mold Inspection Riverside, CA January 24, 2012 - 6:29 pm

@David: It depends on how intrusive the mold problem is. Most likely you can clean your TV and computer and keep using them. But you might need to open them up and see if mold is growing inside. If not, you can probably clean the outside and keep them. If mold is growing inside, you’ll need to figure out if you can clean the mold or if it’s grown onto sensitive components. Hope that helps!

Nebraska Mold Removal February 2, 2012 - 11:37 pm

The five levels of mold removal should be helpful to property owners by helping them decide how to proceed with the mold remediation. Very simple yet instructional. Good, simple resource…clearly written. Thanks!

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Mold remediation great neck September 17, 2012 - 6:55 am

Very vital information about mold as it is very dangerous for human beings in many aspects.It cause illness,property loss and many other problems so its better to get rid of mold and mildew as soon as possible.Good info. to share.

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Provided a very vital information regarding mold and mildew and their remediation companies.Its good to call professional for its removal to remain allergic free.

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This is really very great info regarding mold remediation service. The five levels of mold removal should help the property owners to decide them how to proceed with the mold remediation.

Omar Rehman May 20, 2013 - 9:18 am

So, my wife and I purchased a condo over three weeks ago and the soap dish in the master bath fell off the wall. There was black mold around the area. I kept it damp before I could figure out what to do with it. After talking to folks, I removed the surrounding tile and cut away the bad dry wall to replace it. I damped the area when I did it, but I didn’t seal anything or cover anything in the bathroom. Is this going to be a major problem? I threw the bad pieces into a trash bag and sealed it up before taking it outside. Am I at risk for further infestation? Also, would spraying the area down with baking soda kill any residual mold before putting up new drywall? Thanks!

Restoration Express May 29, 2013 - 10:46 pm

Informative post! Many homeowners do not know the level of damage when it comes to mold. This is a good guide in knowing if the problem already requires professional help.

Odour Removal July 22, 2013 - 4:00 am

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Claire October 29, 2013 - 11:43 am

Wow, its incredible what lengths mold remediation companies have to go through in order to truly alleviate a problem. While there are a ton of DIY home remedies, sometimes it really is best to leave this up to a professional. This article is really insightful, especially for someone trying to understand a pricing quote for a remediation project.

Sam Simon November 10, 2013 - 8:09 am

Thank you for posting this blog. Mold, as naturally occurring as it is and despite the fact that we live with mold in various degrees, mold is quite dangerous when it lives inside of your work or living space. We stress that to home and business owners all the time. Sometimes to no avail. Mold Remediation is a serious process and mold removal companies should be wisely chosen.

Sam Simon
Chicago, Illinois

Scott December 9, 2013 - 8:18 am

Thanks David. It can be difficult to education a homeowner about all of the variables that go into a mold remediation. This is very helpful and will give a mold restoration company a nice way to articulate this piece of it. Thanks.

Mold Removal Fort Lauderdale December 19, 2013 - 7:54 am

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platinuminc October 20, 2014 - 4:11 pm

Great information! I’ve been having the same problems on my ceiling, my boyfriend and I, we were planning to burn them with torch light. At the moment, we are just searching for precautions and tips and so far, this blog helped. Thanks!

Scot LaVelle October 27, 2014 - 4:13 am

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Our site http://www.moldhold.com offers an effective source containment product that actually sticks to wet surfaces including mold.

Valerie D December 8, 2014 - 1:48 pm

Thanks for the informative blog. I have bookmarked your site for future reference.

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John Griffin December 9, 2014 - 7:17 am

Good information. In NJ at least mold companies are only regulated as home improvement contractors. When selecting a testing or remediation firm, ask for references and do check them ! You would not believe what we have run into – the scare tactics and price gouging. Hope this helps

Captain Steamer December 10, 2014 - 12:40 pm

A very interesting article, I think people need to know the levels so they can anticipate the clean up.

Jana Michaels January 15, 2015 - 5:02 am

Here in our area of Florida, because of the humidity, mold is a big problem. It is so scary to go into a house where there are children and the parents don’t take the danger seriously! I’m going to have my team refer people to your site to help them see the importance of prevention and properly remediation.

Kimberly January 22, 2015 - 9:52 am

My mom is 65 in hospital. Just had 4 surgerys in less than a month. Also has been hospitalized the last 3 1/2 monthe out of 4. Her home has level 3 to 4 mold in the walls and insulation. Should she be in her house? Also if not, who do I contact to have herself and my sister forced from the home till the mold is properly removed?

Barbara January 29, 2015 - 1:12 pm

My daughter has a 6 month old and had her home tested, they told her she had a 5 for mold, but no one will tell her what that means, can you help me… thank you

Delores Lyon February 10, 2015 - 1:14 pm

I had no idea that mold could get into your HVAC system and then spread everywhere. That sounds like it could be a major disaster! I will definitely be sure to turn off my HVAC system if I ever come across any mold. I need to make sure that my home is clean and mold free. http://www.aeconllc.com

Effective Basement February 20, 2015 - 11:42 pm

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Mould Cleaning Service March 3, 2015 - 8:25 pm

Nice blog. These tips are very informative and useful. I like your post very much. Thanks to sharing the valuable information.

Laila April 16, 2015 - 12:40 pm

I have also heard that you have to be really careful when removing mold because you can release spores into the air where they can attach and grow on other parts of the house. I am pretty sure my friend had a level 5 because his air conditioner smelled really bad in the summer and I honestly thought it was something that had died. That is one of the worst kinds of mold growth because they can spread like wildfire through the air.

Gener Ortiz June 9, 2015 - 5:05 pm

Hi! I am looking for this kind of information. It will definitely help me with my project. Thank you for sharing this informative post.

Johnathan Smith June 16, 2015 - 7:34 am

Mold is a very nasty thing to deal with! Make sure to contact a professional for tips and services.

Bahram August 4, 2015 - 6:38 pm

Well I think I posted a comment on this blog about 10 days ago, but it did not pass being posted. About 10 days ago, we started getting light musk/mold smell which got me really concerned from the A/C air vents… In a matter of few days, it got stronger and stronger and before you know it, it’s in everything in the house from furniture to appliances. The A/C which is a less than a year old Trane is also stopped working (this is where the fumes are coming from)… Is there anyway to remediate this or the house is gone??? it’s on everything and invisible… Even my whole body smells like this crap…

Cheryl Smith October 22, 2015 - 10:55 am

We had some mold that we recently cleaned up. I wish we would have known about using a HEPA vacuum. It would have made the clean up a little easier. Next time, we will have a little more experience.

Norran November 5, 2015 - 6:28 pm

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Mcquedia November 17, 2015 - 3:41 pm

I observed that mould can appear every were like on bread cheese and other things but there is a way we can help stop it

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April Cook July 19, 2016 - 9:53 am

I noticed some mold in my basement and I am scared to see how much there really is. From what I can see it looks like level I. How can I tell if it is in the walls or the HVAC? Will I need to hire a remediator to come and evaluate the damage? Should I do this before I attempt to clean it up by myself? Thanks for all this great information!

Kathrina Lewis July 23, 2016 - 11:07 am

Amazing post. These 5 levels of mold remediation briefly described that how to tackle a problem like mold damage. I have read several articles but i really found this one helpful as it clears me the process of mold remediation. I totally agree with the 5 levels of mold remediation but i also want to differentiate between mold remediation and mold removal . Here is the difference between both of them http://www.floodaz.com/mold-removal/

Erika Brady October 24, 2016 - 9:18 am

I did not realize that there were different levels of mold remediation. I think there is a spot in my home that is a level 1. I am glad that this is not too bad. I do suffer from asthma, so I will make sure I do not clean it myself and get some help. Thank you for this information!

gilbert turo January 16, 2017 - 8:17 pm

Is it ok to live in a house that has mould in a sealed off room?

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Callum Palmer April 23, 2018 - 2:27 pm

Wow, I didn’t actually know that there were different levels of mold remediation. I always just thought that the company came in and took care of the mold. If that is the case, then it is pretty great to have a better understanding of what the people are doing when they remediate the mold from your home.

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jlowy November 16, 2018 - 2:27 am

Pleasure – thank you for reading!

Devin Scott October 14, 2019 - 10:48 am

It’s fantastic to learn that you shouldn’t clean mold if you have asthma. My wife and I are wondering how to clean mold out of our basement if it floods. I’ll let her know that she shouldn’t ever clean mold since she has asthma.

Jerry Woods November 20, 2019 - 7:45 am

It’s good to learn that you shouldn’t try to clean mold if you have asthma. My wife and I are moving into an older house soon and we were wondering how we should renovate the home when we have asthma. I’ll be sure to get a professional to repair the house if there’s mold in it.

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Hello! I am looking for this kind of information regarding Mold Removal in Toronto. It will definitely help me with my project. Thank you for sharing this informative post.

David Norriss December 6, 2019 - 6:20 am

I like how you explained that if a mold infestation is ever 100 square feet or greater then it is better to call in professional mold remediators. They will be able to properly decontaminate and seal off your house from being infected more. This is important because of how dangerous mold can be especially if it is of this size. Thank you for helping people to know when they should call in a mold remediation service.

Travis Smith May 19, 2020 - 1:17 pm

It’s good to learn that you should hire a professional for mold remediation if you have asthma or an immune disorder. My wife and I are moving into an older home and I want to make sure our house is protected from mold since she has asthma. I’ll be sure to tell her that we should hire a professional to check if there’s mold in our house so she doesn’t get sick.


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