The first step to drying a structure is extraction, which may include removal of wet materials, and then evaporation. The extraction phase removes most of the liquid water and then evaporation removes the remaining liquid water and “draws” the moisture out of wet materials (drywall, plywood, framing lumber, etc).
The water removal process is optimized by first doing a good extraction to remove as much of the liquid water as possible and then using Psychrometry to set up a drying system that maximizes drying efficiency.
Water Removal Process
The water removal process which involves assessment, documentation, controlled drying and selective replacement is the procedure used to recover from many forms of water damage. Due to the large number of factors that influence the drying process, a water damage restoration technician will have to frequently review and modify the tools, systems and science needed for restorative drying.
All materials that are determined to be restorable are inspected further, and the amount of moisture absorbed by the material is measured and documented. Knowing how wet a material is will influence the number and types of equipment used. This is necessary in order to determine if drying progress is being made and is noted during daily monitoring visits. If materials are making significant progress after the initial 24 hours of drying, then drying will continue with no major changes occurring to the process.
The restorer continues to observe progress until drying is complete. If the drying process is not working, a water damage restoration technician will modify the drying environment by adding or subtracting equipment or possibly removing wet, non-salvageable materials.
Water Moisture And Structural Drying
Water affects materials indirectly. Excessive moisture leads to elevated humidity. Many building materials will absorb excess water vapor and suffer damage, especially when the air in the structure is allowed to remain above 60% relative humidity.
Once the damage has been established as Category 1, structural drying can proceed. No substantial departure from standard procedures for addressing contamination is needed.
It is possible to effectively restore the structure to a pre-loss condition by thoroughly and rapidly drying materials, and by replacing only materials with permanent structural or aesthetic damage.
In-Place Drying System
While there are many methods for drying structural components and contents, the “in-place” drying system has been taught in the industry and used by drying contractors since the early ’80s.
In those days, this method of drying components, without significant removal of furnishings or fixtures, was somewhat restricted, due to limitations imposed by extraction, evaporation and dehumidification equipment.
In recent years, however, drying technology (extraction, evaporation, dehumidification), along with better understanding of Psychrometry, has advanced in major ways so that in-place drying has, in some cases, become far more safe and practical.
Natural Ventilation And Dehumidification
Allowing natural ventilation and evaporation to work is better for the building than using heated forced-air or air conditioning systems. The rapid drying out of a historic building using hot air power drying systems can cause irreparable harm to significant features of the building.
Dehumidification is set-up within the water damaged area(s) depending upon power availability and the type of drying equipment available. A supplemental electrical power source may be necessary in some buildings.
Natural And Controlled Drying
Efforts to promote natural and controlled drying out of the building should start at the attic. If the insulation is wet, remove it and dispose of properly.
After being wet, most insulation is ineffective, but it will continue to hold moisture for a long time and will create high moisture conditions which will damage metal, masonry, and wood.
Remember that air circulation is the key to completely drying out a structure. Heaters or air conditioners should not force the drying process. If you force your building to dry too quickly, additional damage to the building elements will occur.
Controlling Moisture Intrusion
The source of water intrusion must be stopped and any further moisture intrusion controlled in order for the restorative drying effort to return the structure and contents to an acceptable condition. The technician will determine whether any building materials in the affected areas could suffer potentially secondary damage.
Following the Initial Loss Assessment, daily records of moisture levels in the structure will assist in communicating the importance of each consecutive step in the water removal process.
Restorative drying is a dynamic process in which a number of variables are constantly influencing the restorer’s intended result: returning the structure to a clean, dry and safe living environment.
The nature of these variables demands that drying environments be closely monitored to ensure that the intended results are realized. This requires a thorough initial inspection to identify items that will influence the restorer’s end goal, followed by frequent monitoring to ensure that expected progress is being made.
Once a building has been exposed to a large volume of Water, either floodwater or rainwater, steps must be taken to dry the building out, assess damage, and plan for restoration. Flooding may be quick, but drying out a building is a time consuming effort.