Mould Remediation

Chart outlines basic procedures to follow

"Take it one step at a time."

 

The summer 1999 issue of this magazine (Volume 10, Number 2) included a detailed article on the recognition, assessment, and control of mould in buildings and other structures.

The chart that follows summarizes mould control procedures recommended by the Environmental Protection Agency in the United States.

For various kinds of material, the chart indicates how mould growth can be prevented within 24-48 hours of water damage and also provides general advice on remediation. This information is intended only as a summary of basic procedures and is not intended, nor should it be used, as a detailed guide to mould remediation.

 

Although the chart may look complicated, it becomes clear and useful when taken one step, or one ring, at a time.

1. Start at the centre.
2. In the first ring, identify the material you are concerned about.
3. In the next ring, find out what actions to take within the first 24-48 hours of CLEAN water damage. Actions are numbered 1, 2, 3, 4, and so on. Each is spelled out under the Action within 24- 48 hrs column outside the chart.
4. Proceed to the next ring if mould growth is apparent and more than 48 hours have elapsed since water damage. Determine whether the contaminated area is less than 10 square feet, between 10 and 100 square feet, or greater than 100 square feet.
5. Proceed to the next ring and follow the clean-up method indicated for the size of the contaminated area. Methods are lettered A, B, C, and D. Each is spelled out under the Clean-up Methods column.
6. In the next ring, determine the level of personal protective equipment required. This is indicated by M, L, or F under the PPE column.
7. Finally, in the outermost ring, determine whether containment is necessary and, if so, whether it must be L (limited) or F (full). These requirements are explained in the Containment column.

Action within 24-48 hrs.

Actions are for damage caused by clean water. If you know or suspect that water is contaminated by sewage or chemical or biological pollutants, consult a professional. Do not use fans unless the water is clean or sanitary. If mould has grown or materials have been wet for more than 48 hours, consult Clean-up Method in chart.

1. Discard non-valuable items.
2. Photocopy valuable items, then discard.
3. Freeze (in frost-free freezer or meat locker) or freeze-dry.
4. Remove water with water-extraction vacuum.
5. Reduce humidity levels with dehumidifiers.
6. Accelerate drying process with fans and/or heaters - Don't use heat to dry carpet - Use caution applying heat to hardwood floors.
7. Discard and replace.
8. May be dried in place, if there is no swelling and the seams are intact. If not, then discard and replace.
9. Ventilate wall cavity.
10. For all treated or finished woods, porous (linoleum, ceramic tile, vinyl) and non-porous (metal, plastic) hard surfaces, vacuum or damp-wipe with water or water and mild detergent and allow to dry; scrub if necessary.
11. For porous flooring and carpets, make sure that subfloor is dry. If necessary clean and dry subfloor material according to chart.
12. Wet paneling should be pried away from walls for drying.

Clean-up Methods

Methods are for damage caused by clean water. If you know or suspect that water is contaminated by sewage or chemical or biological pollutants, consult a professional. These are guidelines only. Other cleaning methods may be preferred by some professionals. Consult Action within 24-48 hrs in the chart if materials have been wet for less than 48 hours and mould growth is not apparent. If mould growth is not addressed promptly, some items may be damaged beyond repair. If necessary, consult a restoration specialist.

1. Wet-vacuum the material. (In porous material, some mould spores/fragments will remain but will not grow if material is completely dried.) Steam cleaning may be an alternative for carpets and some upholstered furniture.
2. Damp-wipe surfaces with water or with water and detergent solution (except wood - use wood floor cleaner); scrub as needed.
3. Use a high-efficiency particulate air (HEPA) vacuum once the material has been thoroughly dried. Dispose of HEPA-vacuum contents in well-sealed plastic bags.
4. Remove water-damaged materials and seal in plastic bags inside containment area, if there is one. Dispose of as normal waste. HEPA-vacuum area once it is dried.

PPE (Personal Protective Equipment)

Use professional judgment to determine PPE for each situation, particularly as the size of the remediation site, and the potential for exposure and health effects, increase. Be prepared to raise PPE requirements if contamination is more extensive than expected.

M - Minimum - Gloves, N-95 respirator, goggles/eye protection.

L - Limited - Gloves, N-95 respirator or half-face respirator with HEPA filter, disposable overalls, goggles/eye protection.

F - Full - Gloves, disposable full-body clothing, head gear, foot coverings, full-face respirator with HEPA filter.

Containment

Use professional judgment to determine containment for each situation, particularly as the size of the remediation site, and the potential for exposure and health effects, increase.

NR - None Required

L - Limited ­ From floor to ceiling, enclose affected area in polyethylene sheeting with slit entry and covering flap. Maintain area under negative pressure with HEPA-filtered fan. Block supply and return air vents in containment area.

F - Full - Use two layers of fire-retardant polyethylene sheeting with one airlock chamber. Maintain area under negative pressure with HEPA-filtered fan exhausted outside of building. Block supply and return air vents in containment area.

Notes

1. Upholstery may be difficult to dry within 48 hours. For items with monetary or sentimental value, consult a restoration specialist.
2. Follow manufacturer's laundering instructions.

 

With grateful acknowledgment, based on Mold Remediation in Schools and Commercial Buildings, published by the United States Environmental Protection Agency, March 2001.