ICS Magazine

Choosing the Most Effective Drying Technique

March 10, 2008

Drying science has advanced to the point where nearly any material item in a structure can be dried. There are many tools and techniques to achieve drying goals, and a true professional will have all of these tools at their disposal. Since everything can be dried, the critical question in restorative drying is “Should it be dried?”

Factors to Consider

One of the first steps in a water loss is determining “What is wet?” in the structure. Then it must be determined which wet items will be dried, and which will be replaced. When determining if a wet material or item should be dried, restorers consider three factors:
  • Contamination
  • Damage
  • Cost
Contamination must always be the first consideration when determining if a material should be dried. Porous items that are affected by Category 3 water, for example, must be removed.

Damage is also an important consideration when choosing a drying method. If a material or item is damaged beyond economical repair, it is removed from the structure. For example, fallen ceilings, insulation that is packed down, and particleboard furniture that is beyond repair are all discarded.

Cost is the final consideration in choosing a drying method. It must cost less to dry an item than to replace it. For example, a base cabinet installation that is affected by water may cost $1,500 to replace. Therefore, drying the cabinet must cost less than $1,500 in order to be practical. Costs evaluated must include replacement and historical value, additional wiring and business interruption.

Many restorers aim for a drying cost of at least 50 percent less than replacement. When estimated costs for drying exceed the 50 percent threshold, the restorer communicates openly with all parties to ensure the customer is involved in the decision-making process. Restorers must thoroughly document the outcome of this communication and the final decision.

“Should it be dried?” is the primary question. If restoration has been ruled out after evaluating the level of contamination, damage and costs, then the items are removed. On the other hand, if restoration is supported, the item is dried.

Two Options

After making the decision of whether or not to dry a material, restorers begin evaluating how to begin the restoration work. There are many methods available – each applying a different combination of humidity control, temperature, airflow and physical manipulation of the material (e.g. removing finish materials, injection of airflow, perforation, etc.).

Restorers use the information obtained during evaluation of materials to help select the best drying method for the job. Generally, there are two primary methods to promote drying of affected structures: disruptive methods and aggressive methods.

Disruptive methods involve removing wet items, injecting air to speed drying, or perforating surfaces (“RIP”) to allow water to evaporate. The term disruptive is used because repairs will be required once the structure has been dried. Use disruptive methods when contamination, damage, cost or customer concerns require removal or manipulation of the affected material. Examples of disruptive drying include:
  • Disposing carpet underlay after Category 2 water intrusion
  • Discarding damaged baseboard
  • Removing vinyl flooring to promote drying of underlayment
  • Perforating vinyl wallpaper
  • Drilling holes in order to inject air into wall cavities with an inter-air drying system
  • Cutting out wallboard to remove wet blown-in insulation
  • Disposing damaged particleboard furniture
As mentioned earlier, whenever these methods are employed it is important to evaluate the cost of replacement and repair. The greater the value of the item, the more likely the owner will want it to be dried.

Aggressive or “in place” drying methods involve leaving wet items in the structure and drying them in place using warm, dry direct airflow. Aggressive methods are used when contamination and damage are not concerns, and when it is cost effective to dry an item instead of replacing it.

Restorers may use aggressive drying methods when all the following are true:
  • The water intrusion came from a sanitary source
  • The structure has been wet for less than 72 hours
  • Drying carpet and underlay in place will not cause damage to hardwood below the carpet
  • Adequate dehumidification is available and usable on site
  • Deep extraction tools are available
When aggressive drying is used, the water intrusion will be classified as a Class 2 or Class 3 because of the additional moisture being left in the environment.

So Which Method is "Correct"?

A great amount of restorers’ energy has been spent debating which method of drying is the correct way to dry a structure – disruptive vs. aggressive (in-place)? In fact, both methods are viable ways to reach the desired goal, which is to return a structure to pre-loss condition. Furthermore, in nearly every structural drying project, both methods are used. In other words, even in an in-place drying scenario, some items may be removed. Each restorative drying job requires an appropriate balance of disruptive and aggressive methods. Where each job ends up on the disruptive or aggressive scale depends upon the amount of contamination and damage present, and the cost-effectiveness of drying wet items. The ultimate goal is to implement the most cost-effective combination of each method, uniquely balanced on a case-by-case basis.

Adjust drying procedures daily. A good general practice during the initial inspection process is to assume an aggressive structural drying approach. Restorers diligently search for any obstacles to this aggressive approach, and modify the aggressive process accordingly. Wherever obstacles are absent, the aggressive approach remains the method of choice.

After a thorough initial inspection, extraction and demolition, restorers install equipment. They then inspect every affected material and document the amount of moisture.

After 24 hours (or less) of drying, all affected materials are re-inspected to determine if significant drying progress was made. As each material’s progress is documented, equipment and processes are adjusted as follows:
  • Material Is Drying – If the material is drying, continue with the current drying approach. It is working properly.
  • Material Has Dried – If the material has achieved its drying goal, reposition equipment to focus on other areas, or remove unneeded equipment from the structure.
  • Material Is Not Drying – If the material is not making progress, modify the drying approach. It is not working. Modification may be made to the equipment or the material, depending upon which is most efficient.
What if materials are not drying? The absolute constant in a wet structure is change. For the restorer, the task is to direct this change in the desired direction: toward the drying goals. If the desired change is not evident (e.g., significant drying progress), it is necessary to re-evaluate the drying method:
  • Contamination – Now that it has been wet for another 24 hours, is there a concern for contamination? Can this contamination, if present, be treated properly? Should the material be removed to ensure complete removal of the contaminant, if present?
  • Damage – Now that the material has been wet for another 24 hours, has permanent secondary damage become evident, such as warping, swelling, splitting or staining? Can the damage be restored, cost-effectively?
  • Cost – The current approach is not working and must be changed. What will result in the lowest cost – removal and replacement or more aggressive drying (e.g., more equipment)?

Using this approach of assessment and ongoing re-evaluation ensures that the structure is being thoroughly and properly dried for the lowest possible cost. Restoration (and profit) will be maximized, reducing the amount of time necessary for repairs and reconstruction. Customers will regain access and normal occupancy of their structure as soon as possible. Insurers will close their claim files quickly. The documentation that results from thorough, daily monitoring will also ensure that the file remains closed and that "come back" claims will not haunt the restorer, the customer or the insurer.

Another benefit to this approach is the minimal labor necessary during the emergency response. Labor rates are typically much higher during the initial response, which is often performed during non-business hours. Because materials are only removed if it is obvious that they will be difficult to restore in place, labor costs can be minimized.

Additionally, when materials are removed, the reason for removal is very apparent and can be thoroughly documented. Materials are removed only when damage or contamination dictates, when cost limitations are obvious, when customers mandate, or when drying progress is not evident in the first 24 hours.