AUBURN, Ala. – Flooding can cause major damage to buildings and homes. After severe weather, homeowners begin the task of drying out after the floodwaters recede. Before entering any building, make sure it is structurally sound. The following are steps for drying out after a flood.
Drying Out the House
To begin, remove as much water as possible, using pumps, wet-dry vacuums, squeegees, etc. Empty only one-third of the water in a flooded basement per day. Rapid water removal may cause the basement walls to collapse. Mechanically remove as much water as possible. This is easier than drying by evaporation. Remove mud silt. If flooding involved polluted water, additional cleaning and sanitizing will be necessary. A wet building needs to dry out once you remove all water. The contents will need to dry or be throne away. If electricity is available, fans greatly increase the evaporation rate if the air the fan is moving is dry.
Fans must be combined with a method of removing moisture from the air, such as some type of dehumidification or ventilation air exchange pulling in warm, dry exterior air and exhausting damp inside air. Electric space heaters can provide heat, but large heaters will warm the air enough to efficiently dry. Fuel-fired heaters produce large amounts of moisture, so they are of limited value unless the heaters are vented to the outdoors. Burning a gallon of kerosene produces about a gallon of moisture. Professional equipment includes refrigerant equipment desiccant dryers.
Walls must be completely dry before you can rebuild. Mold grows in wet walls that are closed up before they dry. Sometimes wet plaster can be recovered if it has not separated from the lath. Usually, wall board or plaster is torn out to the flood line in increments of 2 feet, and replaced by half or whole sheets of drywall. If future flooding is a possibility, consider using paperless drywall. Discard wet insulation. Clean wall cavities if they are moldy. Allow walls to dry before closing them up. Mold is a hazard and you must remove it before living in the house.
Know What You Are Dealing With
There are three types of floodwaters–clean water, gray water and black water.
Water is clean and poses no threat to human health. This is from a roof leak or broken water pipe. This type is also called Category 1.
Water contains significant chemical, biological or physical contamination. This water can cause discomfort or sickness in humans. This type is also called Category 2.
Water contains biological agents coming from sewage or other sources that are likely to cause discomfort or illness. All seawater, ground surface water, or water rising from rivers or streams fall into this category. This type is also called Category 3. This water will have silt in it and perhaps other foreign matter and is considered very unsanitary.
Both gray and black water need special measures for cleanup and sanitizing. Professionals with specialized training are best to work in areas with such contamination. If you must enter, be sure to wear gloves, boots, goggles, a suitable respirator and protective clothing. This contamination poses significant health threats. Use cleaners to wash all flooded surface, then sanitize using a solution of 1 cup of chlorine bleach to 1 gallon of water. The surface should stay moist for 10 to 15 minutes for the sanitizing to occur.
The Alabama Cooperative Extension System has an iBook to help families, businesses and communities prepare for storms and clean up after they pass. The Emergency Handbook is a comprehensive resource for emergency planning, preparation and storm recovery. It is available as a free download from iBooks.