How to Remove Mold—and Know When to Hire Experts

On Jan. 31, Mayor Bloomberg and the Mayor’s Office of Housing Recovery Operations announced a new public-private initiative to help expand mold treatment assistance in Hurricane Sandy-affected neighborhoods. Using private money raised to assist victims of Hurricane Sandy, the Mayor’s Fund to Advance New York City launched a remediation program to remove mold in approximately 2,000 homes in the hardest hit areas.

     The issue of mold cleanup has been on the forefront of officials’ minds as the rebuilding effort continues after Hurricane Sandy. “Mold is one of the biggest public health challenges to come from Superstorm Sandy,” says Representative Michael Grimm of Staten Island. “If it’s not completely and properly removed, it could lead to a sick house and serious health problems down the road for residents.”

     Mold spores can aggravate existing respiratory problems, particularly asthma—and there was an alarming increase in asthma cases after Hurricane Katrina in New Orleans. “You’re going to see that here in the Northeast,” says Mike Shain of NY Indoor Air Quality Solutions. “Cold helps postpone the growth of mold; humidity is low in wintertime, which gives people a bit of a reprieve. But come May, June, or July, if owners haven’t resolved their issues, mold is going to flourish.”

     Whether a mold problem appears at your building due to a moist environment created by a natural disaster or by faulty plumbing, you need to get rid of the mold as quickly and effectively as possible. Untreated mold conditions can escalate, rotting wood and drywall, and eventually causing structural damage; producing mycotoxins that can cause headaches and serious respiratory problems for tenants; and leading building inspectors to issue either Class B or Class C violations of the Housing Maintenance Code.

     We’ll discuss who should do the mold cleanup work at your building—your employees or an outside expert. And we’ll also discuss recommended methods of mold removal in cases where you or your staff can handle the cleanup.

When to Call in the Mold Cleanup Experts

The guidelines issued by the Department of Health (DOH) in “Guidelines on Assessment and Remediation of Fungi in Indoor Environments” offer recommendations as to when you should hire a professional to deal with a mold problem.

     The guidelines recommend basing the decision on who should handle a mold problem on the amount of square footage affected by mold. The guidelines discussed below apply to most mold problems you’d encounter, but don’t apply to mold found in the HVAC systems of buildings.

     10 square feet of mold or less. If mold is found only in a small area (10 square feet or less)—say, on ceiling tiles or patches of walls—the guidelines say that your employees can take care of the problem. But they suggest that any employees who handle mold problems get special training in proper cleanup methods, personal protection, and potential health hazards.

     10–30 square feet of mold. If mold is found in this amount of space, covering one or two entire wallboard panels, for example, the guidelines say that your employees can take care of the problem. But they should get the same training and protection recommended for cleanups of 10 square feet or less.

     30–100 square feet of mold. If mold is found in this amount of space—say, for example, several entire panels of wallboard are covered with the mold—the guidelines say that while you can try to have your employees fix the problem, it’s smarter to call in the experts. This is especially true if taking care of the problem would most likely generate a lot of dust (for example, if you must knock down plaster walls).

     100 or more square feet of mold. If mold is found in this amount of space—say, the wallboard in an entire room is covered with mold—the guidelines say you should hire a professional mold remediation company to combat the problem. This amount of mold would be too much for your employees to deal with safely.

Recommended Methods of Mold Removal

According to the guidelines, the first thing you should do when faced with a mold problem is to locate and get rid of the source of moisture or humidity that’s causing the problem.

     Then try to get rid of the mold itself. The guidelines caution against painting or caulking over moldy surfaces. The paint is likely to peel. A variety of mold cleanup methods are available. The specific method or group of methods used will depend on the type of material affected.

     Wet vacuum. Wetvacuums are vacuum cleaners designed to collect water. They can be used to remove water from floors, carpets, and hard surfaces where water has accumulated. They should not be used to vacuum porous materials, such as gypsum board. They should be used only when materials are still wet—wet vacuums may spread spores if sufficient liquid isn’t present. The tanks, hoses, and attachments of these vacuums should be thoroughly cleaned and dried after use since mold and mold spores may stick to the surfaces.

     Damp wipe. Whether dead or alive, mold is allergenic, and some molds may be toxic. Mold can generally be removed from nonporous (hard) surfaces by wiping or scrubbing with water, or water and detergent. It’s important to dry these surfaces quickly and thoroughly to discourage further mold growth. Instructions for cleaning surfaces, as listed on product labels, should always be read and followed. Porous materials that are wet and have mold growing on them may have to be discarded. Since molds will infiltrate porous substances and grow on or fill in empty spaces or crevices, the mold can be difficult or impossible to remove completely.

     It’s important to note that dead mold is still allergenic, and some dead molds are potentially toxic. The use of a biocide, such as chlorine bleach, is not recommended as a routine practice during mold remediation, although there may be instances where professional judgment may indicate its use, such as when immune-compromised individuals are present.

     HEPA vacuum. HEPA (High-Efficiency Particulate Air) vacuums are recommended for final cleanup of remediation areas after materials have been thoroughly dried and contaminated materials removed. HEPA vacuums are also recommended for cleanup of dust that may have settled on surfaces outside the remediation area. Care must be taken to assure that the filter is properly seated in the vacuum so that all the air must pass through the filter. The used vacuum filter and contents of the HEPA vacuum must be disposed of in well-sealed plastic bags.

Taking Safety Precautions During Cleanup

The guidelines recommend that you or the professionals you hire take various safety precautions during the cleanup. The precautions needed depend on the amount of square footage affected by the mold. The precautions listed below apply to most mold problems you would encounter, but don’t apply to mold found in the HVAC systems of apartment buildings.

     10 square feet of mold or less. During the mold cleanup, keep the work area unoccupied, the guidelines say. But there’s no need to vacate people from adjacent spaces unless they’re particularly at risk, such as infants or people with serious medical conditions or immune deficiency problems.

     Be sure to place any mold-covered material found in a sealed plastic bag. Building materials and furnishings that are contaminated with mold growth and are not salvageable should be double-bagged using 6-mil. polyethylene sheeting. These materials can then usually be discarded as ordinary construction waste.

     It’s important to package mold-contaminated materials in sealed bags before removal from the containment area to minimize the dispersion of mold spores throughout the building. Large items that have heavy mold growth should be covered with polyethylene sheeting and sealed with duct tape before they’re removed from the containment area.

     And when finished, wipe clean the work areas and any pathways walked on during the cleanup. Also, use proper protection for those doing the work. This includes using N95 disposable respirators (available in most hardware stores), gloves, and goggles.

     10–30 square feet of mold. The recommended precautions are the same as those above, with these additional recommendations:

• Cover the work area with a plastic sheet and seal the sheet with tape to contain the dust before starting the mold cleanup.
• Vacuum the work area and pathways that were walked on during the cleanup with a vacuum containing a HEPA filter.

     30–100 square feet of mold. The recommended procedures to follow are identical to those for 10–30 square feet of mold, with these additional recommendations:

• Use plastic sheeting to seal off ventilation ducts or grills in the work area and to seal off the area immediately adjacent to it; and
• Make sure that not only the work area but the area immediately adjacent to it is unoccupied while the work is being done.