There are three areas of critical damage done by flood waters
- Damage to porous materials. Wallboard will disintegrate if it stays wet too long; wood can swell, warp, or rot; electrical parts can short out, malfunction, and cause fires or shock.
- The mud, silt, and unknown contaminants in the water is now in your house.
- The moisture encourages the growth of mildew, a mold or fungus that can grow on everything.
Take Action As Quickly As Possible
Lower the Humidity
Everything will dry more quickly and clean more easily if you can reduce the humidity and stop the rot and mildew.
- Open up the house. If the humidity outside is lower than it is indoors, and if the weather permits, open all the doors and windows to exchange the moist indoor air for drier outdoor air. When temperatures drop at night, an open house is warmer and will draw moisture indoors. At night, and at other times when the humidity is higher outdoors, close up the house.
- Open closet and cabinet doors. Remove drawers to let air circulate. Drawers may stick because of swelling. Don’t try to force them. Help them dry by opening up the back of the cabinet so air can get into it.
- Use fans. Fans help to move the air and dry out your home. Do not use central air conditioning or the furnace blower if the ducts were under water. They will blow out dirty air that might contain contaminants. Clean or hose out the ducts first.
- Run dehumidifiers to reduce the moisture, especially in closed-up areas.
- Use desiccants. Desiccants are materials that absorb moisture and can be used in drying closets or other closed areas where air cannot move through. Desiccants like those listed below are usually available at hardware, grocery, or drug stores.
- Chemical dehumidifier packs used for drying boats and damp closets.
- Cat litter made of clay.
The temperature is an important factor in dehumidification
It is nearly impossible to answer the question for the duration of a dehumidification universally. But you can say that, when there are optimal conditions most dehumidifications need at least three to four weeks. You may think that it is a quite long time. But three main factors influence the duration of the drying process:
- The right device dimension
- The temperature in the rooms which need to be dried
- The air circulation and ventilation
The water extraction rate of a dehumidifier varies dramatically as the air temperature and/or relative humidity change. The warmer and more humid the air the more water is collected. As the air cools and the humidity falls the amount of water collected falls too.
For example, at 90°F (32°C) and 80% Relative humidity the unit may collect, say 50 pints per day. If the temperature is only 80°F (27°C) and relative humidity is 60% that same unit will collect only 25 pints.
Is that a 50 pint or a 25 pint dehumidifier? The answer is that in Europe it is a 50 pint and in the USA it is a 25 pint unit.
On the one hand the water absorption of the air increases when the temperature goes up. That means that air with 68°F (20 °C) can absorb almost twice as much water than air with 34°F (10 °C). Of course, that is crucial for the drying process because the more water the air can transport the faster the drying works.
On the other hand the temperature crucially influences the partial water vapor pressure (often just called vapor pressure). That vapor pressure rises when the temperature goes up and that accelerates the drying process. When the temperature rises from 34°F (10 °C) to 68°F (20 °C) twice as much water can be absorbed by the air out of the wall.
For a quick drying process temperatures between 59°F (15 °C) and 77°F (25 °C) are ideal. When it is colder the dehumidification takes much longer. In such a case you can heat up the rooms with electric heaters. I
Temperatures over 77°F (25 °C) are not useful as well because most of the produced heat gets lost through the outer walls and heating just is inefficient. Extremely high temperatures can even harm the building structure.
When heating up for any reason is not possible an alternative to condensation dryers are adsorption dryers because these dryers also work when the temperatures lie under 68°F 10 °C.
Keep The Air Moving
Improving ventilation can cut the time in half. When the air is doesn’t move the drying process slows down extremely. But you can easily avoid that by moving the air with fans. The faster the air is moving the faster walls dry. From experience, the drying duration takes about half as long when fans are used.