Whenever a homeowner or business owner discovers water damage (regardless of the cause or source), the main basic goal is to get the excess water out of the damaged area, dry everything out, and return humidity levels to normal parameters. Doing this right the first time will prevent a whole host of future problems such as mold. Not doing it right means additional headaches not to mention repair and restoration bills.
The water damage drying process may be accomplished in a number of ways. The Open Drying method involves getting air circulating by opening windows and doors and allowing fresh air into the structure to facilitate drying. This is the most basic of drying methods, and very effective if the weather is fairly warm and dry outside. It also requires the least amount of effort on the part of the property owner as it does away with some or all dehumidifiers since the dry air outside is drying the structure. Air movers or fans will still be required to circulate the air around the water damaged structure. If you live in a cold climate the air could be brought inside and then heated up before circulating it around the building. By nature, cold air is naturally dry since the air cannot hold a lot of water, but heating it is a must in order for it to be able to hold more moisture and prevent condensation. With this method, the indoor air needs to be continually exchanged with the outdoor air to prevent the indoor air from getting too humid which would slow down further drying and could cause secondary damage too.
Sometimes the specific humidity outdoors is considerably higher than the specific humidity indoors which would make an open drying system unfeasible as you would be fighting the outdoor humidity while trying to dry the indoor air. Other factors that could prevent an open drying system would be security, bad weather or air pollution. The Closed Drying method is a bit more involved, making use of a number of high velocity fans, air movers, and other devices to circulate air, moving it across the surface and accelerating evaporation. The more units that can be utilized the better. This is a bit more “hands on” as it requires the units be moved around every few hours in order to ensure complete and thorough drying coverage. Dehumidifiers may also be required to bring down the level of relative humidity to 50% or less. This method is extremely effective; however it does require much more active participation by the property owner.
It is advised to make use of one air moving device per each 10 to 16 linear feet of wall or flooring, making sure the outlet of each air mover points in the same direction. Smaller rooms such as closets or bathrooms may require a unit of their own.
This process of drying through air movement usually tends to aerosolize soils and contaminants. Air filtration devices or scrubbers may be needed to provide additional airflow while removing these soils and contaminants from the room. The Closed Drying method is usually the most closely monitored, keeping track of temp and humidity readings, as well as checking the moisture content of structural wood and other materials with a moisture meter. Monitoring also includes checking on equipment operation, progress of the drying process, and overall indoor environmental quality. Section 12.1.25 of the IICRC S500 Standard states that “If moisture measurements do not confirm satisfactory drying, restorers should adjust drying procedures and equipment placement, or possibly add or change equipment to increase drying capability.”
It is possible to combine the benefits of both the open drying system and closed drying system in one system – this is called the combination drying system. The combination system is exactly what it sounds like, making use of both natural and artificial elements such as dehumidifiers to enhance the drying process, and in many cases it can provide the fastest results. Most water damage restoration companies employ this method and open and close the doors and windows as and when appropriate. It’s not uncommon to arrive at the home to take moisture readings and find the humidity outside is much lower then inside, so the building gets “burped” by opening all the doors and windows and exchanging all the air in the building. Once this is done then the doors and windows get closed again and the already installed dehumidifiers and air movers take over again. Remember, time is of the essence when it comes to water damage; there is only about a 48-72 hour window before long term damage is done, like mold growth, and the clock is ticking.
Of course circumstances may vary widely when it comes to water damage scenarios. The IICRC provides additional information on a number of related subjects involving various classes and categorizations of water.