Investigating, Evaluating and Remediating Moisture and Mold Problems

The content on this web page is based on the publication Mold Remediation in Schools and Commercial Buildings[EPA 402-K-01-001, Reprinted September 2008]. Updates have been made to some resources and links.  

Investigating, Evaluating and Remediating Moisture and Mold Problems

• Mold Remediation - Key Steps
• Plan the Remediation Before Starting Work
• Heating, Ventilation, and Air-Conditioning (HVAC) System
• Hidden Mold
• Remediation
• Table 1: Water Damage Cleanup and Mold Prevention
• Table 2: Mold Remediation Guidelines
• Cleanup Methods
• Personal Protective Equipment (PPE)
• Containment
• Equipment
• Sampling
• How Do You Know When You Have Finished Remediation/Cleanup?
• Footnotes

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Mold Remediation - Key Steps

• Consult health professional as appropriate throughout process
• Select remediation manager
• Assess size of mold problem and note type of mold-damaged materials
• Communicate with building occupants throughout process as appropriate to situation
• Identify source or cause of water or moisture problem
• Plan remediation, adapt guidelines to fit situation, see Table 1 Table 2
• Select personal protective equipment (PPE)
• Select containment equipment
• Select remediation personnel or team
• Choose between outside expertise or in-house expertise
• Remediate
• Fix water or moisture problem
• Clean and dry moldy materials See Table 2
• Discard moldy items that can't be cleaned
• Dry non-moldy items within 48 hours See Table 1
• Check for return of moisture and mold problem
• If hidden mold is discovered, reevaluate plan

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Plan the Remediation Before Starting the Work

Remediation Plan

Assess the size of the mold and/or moisture problem and the type of damaged materials before planning the remediation work. Select a remediation manager for medium or large jobs (or small jobs requiring more than one person). The remediation plan should include steps to fix the water or moisture problem, or the problem may reoccur. The plan should cover the use of appropriate Personal Protective Equipment (PPE) and include steps to carefully contain and remove moldy building materials to avoid spreading the mold.⁽²⁾ A remediation plan may vary greatly depending on the size and complexity of the job, and may require revision if circumstances change or new facts are discovered.

The remediation manager's highest priority must be to protect the health and safety of the building occupants and remediators. It is also important to communicate with building occupants when mold problems are identified.⁽³⁾ In some cases, especially those involving large areas of contamination, the remediation plan may include temporary relocation of some or all of the building occupants.

The decision to relocate occupants should consider:

• The size and type of the area affected by mold growth
• The type and extent of health effects reported by the occupants
• The potential health risks that could be associated with debris
• The amount of disruption likely to be caused by remediation activities

If possible, remediation activities should be scheduled during off-hours when building occupants are less likely to be affected.

Remediators, particularly those with health-related concerns, may wish to check with their doctors or health care professionals before working on mold remediation or investigating potentially moldy areas. If you have any doubts or questions, you should consult a health professional before beginning a remediation project.

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Heating, Ventilation, and Air-Conditioning (HVAC) System

Do not run the HVAC system if you know or suspect that it is contaminated with mold. If you suspect that it may be contaminated (it is part of an identified moisture problem, for instance, or there is mold growth near the intake to the system), consult,

• EPA's guide Should You Have the Air Ducts in Your Home Cleaned? ⁽⁴⁾
• Resources List in this Guide

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Hidden Mold

In some cases, indoor mold growth may not be obvious. It is possible that mold may be growing on hidden surfaces, such as:

• The back side of dry wall
• Wallpaper
• Paneling
• The top of ceiling tiles
• The underside of carpets and pads

Possible locations of hidden mold can include:

• Pipe chases and utility tunnels (with leaking or condensing pipes)
• Walls behind furniture (where condensation forms)
• Condensate drain pans inside air handling units
• Porous thermal or acoustic liners inside ductwork
• Roof materials above ceiling tiles (due to roof leaks or insufficient insulation)

Some building materials, such as dry wall with vinyl wallpaper over it or wood paneling, may act as vapor barriers, ⁽⁵⁾ trapping moisture underneath their surfaces and thereby providing a moist environment where mold can grow. You may suspect hidden mold if a building smells moldy, but you cannot see the source, or if you know there has been water damage and building occupants are reporting health problems. Investigating hidden mold problems may be difficult and will require caution when the investigation involves disturbing potential sites of mold growth—make sure to use personal protective equipment (PPE). For example, removal of wallpaper can lead to a massive release of spores from mold growing on the underside of the paper. If you believe that you may have a hidden mold problem, you may want to consider hiring an experienced professional. If you discover hidden mold, you should revise your remediation plan to account for the total area affected by mold growth.

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Remediation

1. Fix the water or humidity problem. Complete and carry out repair plan if appropriate. Revise and/or carry out maintenance plan if necessary. Revise remediation plan as necessary, if more damage is discovered during remediation. For additional information see:
   • Mold Remediation - Key Steps
   • Resources List
2. Continue to communicate with building occupants, as appropriate to the situation. Be sure to address all concerns.
3. Completely clean up mold and dry water-damaged areas. Select appropriate cleaning and drying methods for damaged/contaminated materials. Carefully contain and remove moldy building materials. Use appropriate Personal Protective Equipment (PPE). Arrange for outside professional support if necessary.

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Table 1: Water Damage Cleanup and Mold Prevention ⁽⁶⁾

Table 1 presents strategies to respond to water damage within 24-48 hours. These guidelines are designed to help avoid the need for remediation of mold growth by taking quick action before growth starts. If mold growth is found on the materials listed in Table 1, refer to Table 2 for guidance on remediation. Depending on the size of the area involved and resources available, professional assistance may be needed to dry an area quickly and thoroughly. See:

• Table 1
• Table 2

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Table 2: Mold Remediation Guidelines ⁽⁷⁾

Table 2 presents remediation guidelines for building materials that have or are likely to have mold growth. The guidelines in Table 2 are designed to protect the health of occupants and cleanup personnel during remediation. These guidelines are based on the area and type of material affected by water damage and/or mold growth. Please note that these are guidelines; some professionals may prefer other cleaning methods. See Table 2

If you are considering cleaning your ducts as part of your remediation plan, you should consult EPA's publication entitled, "Should You Have the Air Ducts In Your Home Cleaned?" ⁽⁸⁾. If possible, remediation activities should be scheduled during off-hours when building occupants are less likely to be affected. See:

• Should You Have the Air Ducts In Your Home Cleaned?
• Resources List

Although the level of personal protection suggested in these guidelines is based on the total surface area contaminated and the potential for remediator and/or occupant exposure, professional judgment should always play a part in remediation decisions. These remediation guidelines are based on the size of the affected area to make it easier for remediators to select appropriate techniques, not on the basis of health effects or research showing there is a specific method appropriate at a certain number of square feet. The guidelines have been designed to help construct a remediation plan. The remediation manager will then use professional judgment and experience to adapt the guidelines to particular situations. When in doubt, caution is advised. Consult an experienced mold remediator for more information.

A more cautious or conservative approach to remediation is indicated in cases in which:

• A particularly toxic mold species has been identified or is suspected
• When extensive hidden mold is expected (such as behind vinyl wallpaper or in the HVAC system)
• When the chances of the mold becoming airborne are estimated to be high
• Sensitive individuals (e.g., those with severe allergies or asthma) are present

Always make sure to protect remediators and building occupants from exposure to mold.

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Cleanup Methods

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Personal Protective Equipment (PPE)

If the remediation job disturbs mold and mold spores become airborne, then the risk of respiratory exposure goes up. Actions that are likely to stir up mold include:

• Breakup of moldy porous materials such as wallboard
• Invasive procedures used to examine or remediate mold growth in a wall cavity
• Actively stripping or peeling wallpaper to remove it
• Using fans to dry items

The primary function of Personal Protective Equipment (PPE) is to avoid inhaling mold and mold spores and to avoid mold contact with the skin or eyes. The following sections discuss the different types of PPE that can be used during remediation activities. Please note that all individuals using certain PPE equipment, such as half-face or full-face respirators, must be trained, must have medical clearance and must be fit-tested by a trained professional. In addition, the use of respirators must follow a complete respiratory protection program as specified by the Occupational Safety and Health Administration. For more information see Resources List.

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Containment

The purpose of containment during remediation activities is to limit release of mold into the air and surroundings, in order to minimize the exposure of remediators and building occupants to mold. Mold and moldy debris should not be allowed to spread to areas in the building beyond the contaminated site.

The two types of containment recommended in Table 2 are limited and full. The larger the area of moldy material, the greater the possibility of human exposure and the greater the need for containment. In general, the size of the area helps determine the level of containment. However, a heavy growth of mold in a relatively small area could release more spores than a lighter growth of mold in a relatively large area. Choice of containment should be based on professional judgment.⁽¹⁰⁾ The primary object of containment should be to prevent occupant and remediator exposure to mold. See Table 2

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Equipment

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Sampling

Is sampling for mold needed? In most cases, if visible mold growth is present, sampling is unnecessary. You may consider sampling as part of your site evaluation in specific instances, such as:

• Cases where litigation is involved
• The source(s) of the mold contamination is unclear
• Health concerns are a problem

Surface sampling may also be useful in order to determine if an area has been adequately cleaned or remediated. Sampling should be done only after developing a sampling plan that includes a confirmable theory regarding suspected mold sources and routes of exposure. Figure out what you think is happening and how to prove or disprove it before you sample.

If you do not have extensive experience and/or are in doubt about sampling, consult an experienced professional. This individual can help you decide if sampling for mold is useful and/or needed, and will be able to carry out any necessary sampling. It is important to remember that the results of sampling may have limited use or application. Sampling may help locate the source of mold contamination, identify some of the mold species present and differentiate between mold and soot or dirt. Pre- and post-remediation sampling may also be useful in determining whether remediation efforts have been effective. After remediation, the types and concentrations of mold in indoor air samples should be similar to what is found in the local outdoor air. Since no EPA or other Federal threshold limits have been set for mold or mold spores, sampling cannot be used to check a building's compliance with Federal mold standards.

Sampling for mold should be conducted by professionals with specific experience in designing mold sampling protocols, sampling methods and interpretation of results. Sample analysis should follow analytical methods recommended by the American Industrial Hygiene Association (AIHA), the American Conference of Governmental Industrial Hygienists (ACGIH), or other professional guidelines (see Resources List). Types of samples include:

• Air samples
• Surface samples
• Bulk samples (chunks of carpet, insulation, wall board, etc.)
• Water samples from condensate drain pans or cooling towers

A number of pitfalls may be encountered when inexperienced personnel conduct sampling:

• They may take an inadequate number of samples
• There may be inconsistency in sampling protocols
• The samples may become contaminated
• Outdoor control samples may be omitted
• You may incur costs for unneeded or inappropriate samples

Budget constraints will often be a consideration when sampling; professional advice may be necessary to determine if it is possible to take sufficient samples to characterize a problem on a given budget. If it is not possible to sample properly, with a sufficient number of samples to answer the question(s) posed, it would be preferable not to sample. Inadequate sample plans may generate misleading, confusing and useless results.

Keep in mind that air sampling for mold provides information only for the moment in time in which the sampling occurred, much like a snapshot. Air sampling will reveal, when properly done, what was in the air at the moment when the sample was taken. For someone without experience, sampling results will be difficult to interpret. Experience in interpretation of results is essential.

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Footnotes:

_{2. Molds are known allergens and may be toxic. You may wish to use Personal Protective Equipment (PPE) while investigating a mold problem, as well as during remediation/clean-up situations. The minimum PPE includes an N-95 respirator, gloves, and eye protection.}

_{3. See Appendix C.}

_{4. Although this document has a residential focus, it is applicable to other building types.}

_{5. Resources List has more information on vapor barriers and building construction. It is important that building materials be able to dry; moisture should not be trapped between two vapor barriers or mold may result. See Resources List}

_{6. Please note that Table 1 and Table 2 contain general guidelines. Their purpose is to provide basic information for remediation managers to first assess the extent of the damage and then to determine whether the remediation should be managed by in-house personnel or outside professionals. The remediation manager can then use the guidelines to help design a remediation plan or to assess a plan submitted by outside professionals. See:}

• _{Table 1}
• _{Table 2}

_{7. Please note that Table 1 and Table 2 contain general guidelines. Their purpose is to provide basic information for remediation managers to first assess the extent of the damage and then to determine whether the remediation should be managed by in-house personnel or outside professionals. The remediation manager can then use the guidelines to help design a remediation plan or to assess a plan submitted by outside professionals. See:}

• _{Table 1}
• _{Table 2}

_{8. Although this document has a residential focus, it is applicable to other building types.}

_{9. If you are unsure what to do, or if the item is expensive or of sentimental value, you may wish to consult a specialist. Specialists commonly listed in phone books include:}

• _{Furniture repair/restoration}
• _Painting
• _{Art restoration and conservation}
• _{Carpet and rug cleaning}
• _{Water damage}
• _{Fire/water restoration}

_{Be sure to ask for and check references; look for affiliation with professional organizations. See Resources List.}

_{10. For example, a remediator may decide that a small area that is extensively contaminated and has the potential to distribute mold to occupied areas during cleanup should have full containment, whereas a large wall surface that is lightly contaminated and easily cleaned would require only limited containment.}

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