Herald JournalHoward Lake-Waverly Herald, July 8, 2002

Tips on mold/mildew clean-up for damaged homes

By Lynda Jensen

The hot and dreary job of cleaning up is in progress for many who are counting their losses local basements June 25.

The following is information from the Minnesota Department of Health about how to clean up and remove mold from flood-damaged homes.

What is mold?

Molds are fungi. Molds grow throughout the natural and built environment. Tiny particles of mold are present in indoor and outdoor air.

In nature, molds help break down dead materials and can be found growing on soil, foods, plant matter, and other items.

Molds produce microscopic cells called "spores" which are very tiny and spread easily through the air. Live spores act like seeds, forming new mold growths (colonies) when they find the right conditions.

Mold cleanup, removal  

The golden rule of cleanup is "when in doubt, throw it out." Also, wash hands thoroughly and often.

To clean up and remove indoor mold growth, follow steps as they apply to your home.

First, identify and fix the moisture problem.

This is the most important step in solving a mold problem; to correct the moisture that allowed the growth in the first place.

To keep indoor surfaces as dry as possible, try to maintain the home's relative humidity between 20 and 40 percent in the winter and less than 60 percent the rest of the year. You can purchase devices to measure relative humidity at some home supply stores.

Ventilation, air circulation near cold surfaces, dehumidification, and efforts to minimize the production of moisture in the home are all very important in controlling high humidity that frequently causes mold growth in our cold climate.

Next, begin drying all wet materials as soon as possible. Many flood victims have already done this.

For severe moisture problems, use fans and dehumidifiers and move wet items away from walls and off floors. Check with equipment rental companies or restoration firms to see if you can rent fans and dehumidifiers.

Next, remove and dispose of mold contaminated materials ­ items which have absorbed moisture (porous materials) and which have mold growing on them need to be removed, bagged and thrown out. Such materials may include Såheet rock, insulation, plaster, carpet/carpet pad, ceiling tiles, wood products (other than solid wood), and paper products.

Likewise, any such porous materials that have contacted sewage should also be bagged and thrown away. Non­porous materials with surface mold growth may be saved if they are cleaned well and kept dry.

· Take steps to protect yourself ­ the amount of mold particles in air can increase greatly when mold is disturbed. Consider using protective equipment when handling or working around mold contaminated materials. The following equipment can help minimize exposure to mold:

· Rubber gloves

· Eye goggles

· Outer clothing (long sleeves and long pants) that can be easily removed in the work area and laundered or discarded.

· Medium-efficiency or high­efficiency filter dust mask (these can be found at safety equipment suppliers, hardware stores, or some other large stores that sell home repair supplies) ­ at a minimum, use an N-95 or equivalent dust mask.

· Take steps to protect others ­ plan and perform all work to minimize the amount of dust generated. The following actions can help minimize the spread of mold spores:

· Enclose all moldy materials in plastic (bags or sheets) before carrying through the home.

· Hang plastic sheeting to separate the work area from the rest of the home.

· Remove outer layer of work clothing in the work area and wash separately or bag.

· Damp clean the entire work area to pick up settled contaminants in dust.

Clean surfaces ­ surface mold growing on non­porous materials such as hard plastic, concrete, glass, metal, and solid wood can usually be cleaned. Cleaning must remove and capture the mold contamination, because dead spores and mold particles still cause health problems if they are left in place.

· Thoroughly scrub all contaminated surfaces using a stiff brush, hot water and a non­ammonia soap/detergent or commercial cleaner

· Collect excess cleaning liquid with a wet/dry vacuum, mop or sponge

· Rinse area with clean water and collect excess rinse water

Disinfect surfaces (if desired) ­ after cleaning has removed all visible mold and other soiling from contaminated surfaces, a disinfectant may be used to kill mold missed by the cleaning. In the case of sewage contamination, disinfection must be performed. Contact the Minnesota Department of Health for appropriate advice.

· Mix 1/4 to 1/2 cup bleach per gallon of water and apply to surfaces where mold growth was visible before cleaning. The solution can be applied with a spray bottle, garden sprayer, it can be sponged on, or applied by other methods.

· Collect any run­off of bleach solution with a wet/ dry vacuum, sponge or mop. However, do not rinse or wipe the bleach solution off the areas being treated ­­ allow it to dry on the surface.

Always handle bleach with caution.Never mix bleach with ammonia - toxic chlorine gas may result. Bleach can irritate the eyes, nose, throat, and skin. Provide fresh air (for example, open a window or door). Protect skin and eyes from contact with bleach. Test solution on a small area before treatment, since bleach is very corrosive and may damage some materials.

Remain on MOLD ALERT ­ Continue looking for signs of moisture problems or return of mold growth. Be particularly alert to moisture in areas of past growth. If mold returns, repeat cleaning steps and consider using a stronger solution to disinfect the area again. Regrowth may signal that the material should be removed or that moisture is not yet controlled.

Can ozone air cleaners remove indoor mold?

Some air cleaners are designed to produce ozone which is a strong oxidizing agent and a known irritant of the lungs and respiratory system.

Studies have shown that ozone, even at high concentrations, is not effective at killing airborne mold or surface mold contamination.

Even if mold was killed by ozone, the health threats would not be reduced until mold contaminants are removed through cleaning.

Health experts, including the Minnesota Department of Health, do not recommend the use of ozone to address mold or any other indoor air problems.

How do I tell if I have a mold problem?

Investigate, don't test.

The most practical way to find a mold problem is by using your eyes to look for mold growth and by using your nose to locate the source of a suspicious odor. If you see mold or if there is an earthy or musty smell, you should assume a mold problem exists.

Other clues are signs of excess moisture or the worsening of allergy-like symptoms.

· Look for visible mold growth (may appear cottony, velvety, granular, or leathery and have varied colors of white, gray, brown, black, yellow, green). Mold often appears as discoloration, staining, or fuzzy growth on the surface of building materials or furnishings. When mold is visible, testing is not recommended.

· Search areas with noticeable mold odors.

· Look for signs of excess moisture or water damage. Look for water leaks, standing water, water stains, condensation problems. For example, do you see any watermarks or discoloration on walls, ceilings, carpet, woodwork or other building materials?

· Search behind and underneath materials (carpet and pad, wallpaper, vinyl flooring, sink cabinets), furniture, or stored items (especially things placed near outside walls or on cold floors). Sometimes destructive techniques may be needed to inspect and clean enclosed spaces where mold and moisture are hidden; for example, opening up a wall cavity.

Cleaning up after a flood

If your business has been involved in a flood, you'll need to observe a few simple precautions as you begin the cleanup process.

This brochure explains how to get up and running again, without jeopardizing your own health ­ or the health of your customers.

Food and beverages

Not all food or beverage items can be saved after a flood. You must discard any items in soft packaging or screw­top glass bottles that may have been in contact with flood water. In some cases, you may be able to save commercially canned goods in metal cans or rigid plastic containers. The condition of the container is crucially important.

To salvage canned goods (in metal cans)

· Remove labels.

· Wash in warm water and detergent.

· Sanitize with a solution of one tablespoon of bleach in a gallon of water.

When relabeling, be sure to include:

· The common or usual name of the product.

· The net contents of the container.

· The name, address, and zip code of the "distributor" (i.e., the firm that relabeled the product). Any label codes from the original label.

· Any other required labeling information.


Only the owner ­ or a licensed salvage professional (known as a "salver") can legally recondition food products.

For more information, call the Minnesota Department of Agriculture at 651/296­2627.

Discard canned goods

· If the surface is rutted or pitted.

· If the can is swollen or leaking.

· If the can is badly creased or dented at the rims or seams.

Salvage items in rigid plastic containers:

· Only if they have not been submerged in flood water or other liquids.

· Only if the product is not contaminated.

· Only if all traces of soil can be removed, and there is no soil on the cap or closure.

· Only if there is no evidence of rusting or pitting on the cap or closure, and the seal is completely intact.

· Only if the cap or crown is not dented in any way that affects the rim seal.

· Only if the container is not defective in any other obvious way.

Salvaging beverage items

· You can salvage corked wine bottles sealed with foil or wax.

· You cannot salvage beverage containers with twist or screw tops.


Thoroughly clean and sanitize all salvageable equipment. Use a detergent and a sanitizing solution made with one tablespoon of bleach in a gallon of water.

You can generally save equipment if. . .

· It is made of stainless steel or other nonabsorbent materials.

· It contains only non­absorbent, closed cell polyurethane insulation. (This material is used in newer refrigerators and freezers. It may require cleaning ­ check with the manufacturer.)

Assume there's mold if . . .

If any materials are still wet or moist after 24 to 48 hours, you should assume they have mold growing on them.

You can disinfect floors or wood surfaces using a solution of 1/4 cup of bleach in a gallon of water (1­1/4 cups bleach to 5 gallons of water). If mold has already begun to grow, use a stronger solution, for example, 1-3/4 cups of bleach to a gallon of water (half gallon (8 cups) of bleach to four and a half gallons of water). It is safer to add the bleach to the water than vice versa.


Some furnishings and fixtures will need to be discarded if they have been in contact with flood water. Some examples are:

· All upholstered furniture, including chairs, bar stools, benches, booth seats, and bar arm rests.

· Any tables or booths that cannot be effectively cleaned and sanitized.


In cleaning up a building:

· Remove stainless steel wall panels and set them aside for later re­installation.

· Open, clean, decontaminate, and dry out cavities in walls, floors, and ceilings. To prevent mold and mildew growth, try to do this job within 24 to 48 hours after the flood waters recede.

· Discard plaster, wallboard, wall paper, paneling or insulation, if it has been in contact with flood water.

· Remove any linoleum or asbestos tile that been flooded, so you can clean and dry the subflooring.

· Linoleum or vinyl asbestos tile can be saved and reused if it can be cleaned and sanitized.

· Thoroughly scrub floors and woodwork within 24 to 48 hours after flood waters recede, using a stiff brush, water, detergent, and sanitizer.

· Discard any ceiling tile or other absorbent materials that have been contaminated by flood water.

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