Stabilization in Water Damage Claims


When a new water damage prospect calls a contractor for assistance, most restorers understand the necessity to respond quickly. It is not uncommon for them to drop everything they are doing and be at the jobsite in less than an hour! Such urgency is expected in order to keep the damages to a minimum.

Once the prospect is signed up with a legal agreement, the contractor is very inspired to immediately do what they know needs to be done on the property. This is especially true if the water intrusion is contaminated water (Category 2 and / or Category 3). In fact, the vast majority of water damage projects are not Category 1 “fresh water” escapes as they have usually degraded to a contaminated condition. The resulting scope of work usually requires the physical removal of materials installed in the structure; gypsum wallboard (yes, gypsum wallboard with absorbed Category 2 water is non-restorable), carpet cushion and/or carpet, insulation, cabinetry, countertops, finishing trims, etc.

But wait… if the customer intends on filing an insurance claim, there are rules in the policy and due diligence required to preserve the integrity of the insurance claim! Consider the contractor’s liability if the insurance claim was denied due to their hasty actions.


Insurance Policies and Standards of Care

Insurance policies usually include language describing a post-loss stipulation requiring the insured to allow the insurer the opportunity to inspect the damaged property “as often as [the insurer] reasonably require[s].” If the contractor starts deconstructing the structure immediately, the insurer is denied this opportunity to inspect and can deny the claim.

This has happened to more than one policy holder paired with an ambitious contractor.

So, what is the claimant and contractor to do in this situation? The insurer has been notified of the claim and they inform the policy holder that a representative will be calling them soon. This anticipated communication from a qualified adjuster extends into days… weeks… even months in some cases. Why, in Florida, insurers have ninety (90) days to determine coverage for a property insurance claim! Insurers seem very uninspired to get to water damage insurance claims quickly, yet that doesn’t change the rules they set in the policy agreement. The trick is not to be blamed for the consequences of adhering to their rules.

To accommodate the language of the policy, if the water is not a category 1 (uncontaminated), the structure must remain wet and unaddressed as everyone waits for the insurer to either conduct their inspection or waive their right to inspect the damages. Surely, every reader of this article is concerned over the microbial and physical damages that such a delay can produce. What is a contractor to do?!

The industry standard S500-2015 Standard and Reference Guide for Professional Water Damage Restoration has a passage that speaks to this subject. Please note §13.3.5 Humidity Control in Contaminated Structures (12.3.5 in the S500-2021):

The priority for restorers is to complete remediation activities before restorative drying. However, the restorer should control the humidity in contaminated buildings to minimize moisture migration, potential secondary damage, and microbial amplification. Restorers should maintain negative pressure in relation to uncontaminated areas. Maintaining negative pressure in an affected area can increase the dehumidification capacity needed to maintain desired psychrometric conditions. This may be implemented before, during, or after decontamination. Restorers should limit the velocity of airflow across surfaces to limit aerosolization of contaminants. Restorers should complete the drying process after the remediation has been completed

Why are so few restorative drying contractors exercising this practice identified as being an element of “the standard of care to be followed?”

Those who follow the industry Standards refer to this phase of mitigation as “Stabilization,” and it has nothing to do with a drying strategy. Stabilization has no intention of drying ANY of these structural materials, although, given enough time, the structure will eventually release its excess moisture… very slowly. And yes, it is frequently a biological nightmare after being wet due to the mandatory delays.

What is a contractor supposed to do?

  • The contractor shouldn’t jeopardize the customer’s insurance claim by denying the insurer of their right and obligation to inspect damages as outlined within their policy.
  • If a structure is or is at risk of becoming a non-Category 1 / non-Condition 1, contaminated project, the structural HVAC System should be isolated from the affected areas (S520-2015 §13.2). Surely, we all understand the risks of enclosing and isolating a wet area with atmospheric controls fully disabled!
  • The contractor shouldn’t initiate a drying strategy until the structure is verified to be in a sanitary condition and this delay can result in a microbial condition that might be excluded or limited in coverage.

As John Travolta said in his movie, Face Off: “What a predicament!”


Stabilization is NOT “Drying”

Delays are common in mitigation. There might be a delay in the mitigation as asbestos testing results are being prepared. Perhaps an engineer is required on the property, and he needs a few days. Some insurance companies have strict policies that deconstruction activities require advance notice and permission from the insurance claim representative(s). Failure to honor these internal corporate rule(s) (it’s not in the insurance policy) are met with harsh responses from claim representative and even payment denial after the work is completed.

Most contractors install a variety of restoration equipment during this delay and refer to it as “Stabilization,” – while failing to understand the unique objectives and method.

Should the contractor simply use the dehumidifier and air mover formulas referenced in past versions of the S500 Standard?

No! These formulas… are NOT appropriate for a stabilization strategy!

The equipment formulas mentioned in the S500 are strictly for the initial period encountered at the start of a drying strategy for the sole purpose of controlling the anticipated spike in humidity once the air movers have been turned on. (S500-2015; page 201, Controlling Humidity & S500-2021; Appendix B)

But air movers are NOT to be used on a contaminated environment, right? (§12.3.5) These IICRC air mover and initial dehumidifier formulae are likely to be incorrect for a competent stabilization strategy.

Regardless of equipment choice or method, all drying strategies are a manipulation of two vapor pressures: atmospheric and internal hygroscopic material, and is called “vapor pressure differential” or, “delta vapor pressure (ΔVP)” with the objective of drying materials to an acceptable moisture content and function, and this is completely different from that of a stabilization strategy.


Stabilization Objectives

In reference to §13.3.5 quoted earlier, stabilization has the sole objective of producing an atmospheric condition that reduces the chances of secondary damage. As a reminder, secondary damage is:

“The wetting or impairment of the appearance or function of a material from prolonged indirect exposure to water or indirect exposure to contamination carried by or resulting from the current water intrusion, which is reversible or permanent.” (Underline added) S500-2015 & 2021; §10.6.5

If the humidity or airborne particulate exceeds acceptable levels, secondary damage – to unaffected materials – can occur. But the wet materials – can – and frequently DO go very biological in a stabilization strategy, the causation of which is the entity who mandated the mitigation limitation.

But what are the stabilization thresholds considered responsible and competent?


Drying Equipment Usage

Stabilization Thresholds

The industry standards define neither drying nor stabilization thresholds, yet we know the stabilization objectives intended: control the risk of damage due to excess humidity and/or the spread of contaminant to unaffected materials.

According to the CDC, the following temperature and humidity thresholds are reported by authoritative government agencies:

“Assuming slow air movement (less than 40 feet per minute) [<0.5 mph] and 50% indoor relative humidity, the operative temperatures recommended by ASHRAE range from 68.5oF to 75oF in the winter, and from 75oF to 80.5oF in the summer. The difference in temperature ranges between the seasons is largely due to clothing selection. ASHRAE also recommends that indoor relative humidity be maintained at or below 65% [ANSI/ASHRAE 2013b]. The EPA recommends maintaining indoor relative humidity between 30 and 60% to reduce mold growth [EPA 2012].”         

We remember from our prior formal education in water damage the learning objective: To control the risk of causing secondary damage, the restorer should keep their relative humidity below… 60%. This threshold has been revised in recent exams to keep the relative humidity below 70% based upon a quote from the IICRC R520 definition of humidity:

“humidity: the measure of moisture in the atmosphere. From an air quality standpoint, humidity in a built environment should be maintained between 30 and 50%, according to the CPSC. Excessive humidity is encountered above 60% relative humidity, with humidity above 70% creating an atmosphere that is conducive to rapid microorganism growth.”

“For these dry-tolerant (or xerophilic) molds, aw of 0.66-0.70 (66%-70% ERH) is sufficient to promote growth.”

S500-2015 page 94 and S500-2021 §2.2 Microbial Amplification

“If water damage events are not mitigated in a timely manner, fungal contaminants will grow and amplify, quickly posing an allergic, toxic, and infectious disease health risk to both occupants and restoration personnel.”

S500-2021 §3.3 Secondary Fungal Contamination

From this information, it can be reasonably stated that a competent stabilization strategy sets a comfortable temperature of 65°F (18°C) to 80°F (27°C) with a Not-To-Exceed threshold of 65% relative humidity.

Therefore, a typical ambient condition during a competent stabilization phase would be 72°F @ 50% relative humidity.

A typical and competent stabilization condition of approximately 72°F @ 50% RH is a lousy drying chamber… but an ideal stabilization condition. [CALL-OUT BOX]


Dust and Particulate Control

But what about dust and particulate that can manifest during the stabilization phase and potentially become airborne? How are thresholds set to justify the use of air filtration devices (AFD)?

“12.3.2 Engineering Controls: Containment and Managed Airflow

Restorers should prevent the spread of contaminants into areas known or believed to be uncontaminated. The procedures in this subsection (12.3.2) may be scaled back as appropriate for less contaminated environments. Contaminants can be spread in many ways:

  • solid and liquid contaminants can be: tracked on feet, spread on wheels or bases of equipment, carried on contents, bulk materials, or debris during manipulation or removal; and
  • airborne contaminants can be spread by natural circulation, an installed mechanical system, or by using air moving equipment. When drawing moist air out of potentially contaminated cavities using negative pressure, an in-line HEPA filter should be used to remove contamination before exhausting the air into the room.”

The value of AFDs in a stabilization strategy can be effectively proven with a quality laser particle counter.

  1. Prior to conducting any restoration activity on the property, collect and photograph a 6-channel laser particle count in the affected area.
  2. Following the protection of contents, water extraction, erection of containment equipped with negative HEPA air filtration per S500-2015 13.3.5 (12.3.5 in the 2021 version), demonstrate the AFD’s value by collecting and photographing another 6-channel particle count in the chamber. Compare to data collected in step 1 to prove the necessity and efficacy of the AFD(s). (Pay particular attention to the PM 2.5µ particle size.)


Stabilization Does / Doesn’t:

The subject of Stabilization is poorly understood by non-restorers (e.g.: claims representatives). Since drying cannot be initiated until after the structure is verified to be sanitary / Category 1,

  • Stabilization strategies are not engineered to dry materials effectively.
  • Air movers are usually not a part of a stabilization strategy.
  • Stabilization strategies should be employed if the chambers are unlikely to remain lower than safe stabilization thresholds of 65F to 80F @ 45% to 60% RH with the objective of preventing secondary damage in unaffected materials. Stabilization does NOT have the objective of preventing further damage in materials affected by the liquid water (primary damaged materials). Pro Tip: Use equipment outfitted with thermostats and humidistats.
  • Stabilization strategies are engineered to prevent microbial growth in UNAFFECTED materials, NOT the wet materials. The wet materials are likely to go “biological” in short order unless addressed quickly – so it is very important to prove the biological condition was caused by delays of others – not the contractor’s. (Document delay details DAILY! Some prudent restorers even collect a few atmospheric mold samples on day 1 to prove there were no mold issues on the first day of the water intrusion. Causation of the mold… matters!)
  • Since stabilization is not a part of a drying strategy, the criteria for drying documentation are not applicable during this phase. (However, this doesn’t mean the stabilization phase is exempt from supportive documentation. Compelling documentation includes periodic tests to show what happens to the atmosphere when the equipment is paused for a period of time.)
  • Pro Tip: Include language in the Agreement that in the event that mitigation requires a stabilization phase, the atmospheric thresholds are defined in the contract as not-to-exceed values and that two scopes of work and two invoices will segregate the mitigation into a stabilization phase and a drying phase. Stabilization are ALL activities (including deconstruction and decontamination) to the point that the structure is tested to be sanitary so that drying can begin. You will find that ¾ of the mitigation services fall into the stabilization phase with only a small portion of the mitigation costs being the drying costs. This segregation of mitigation phases results in many disputes about “drying costs” being quickly dismissed.

The vast majority of water damage projects are NOT Category 1 – unchanged from its “fresh water” source, therefore a stabilization strategy is a standard part of most water damage restoration projects. Yet, the stabilization phase remains poorly understood and frequently omitted much to the demise of all involved.

Segregate your mitigation into two distinct phases – Stabilization and Drying – with two scopes of work and two invoices. You won’t believe how many unreasonable disputes will be a thing of the past.

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Ken Larsen, CR

Ken Larsen
Ken Larsen, CR, WLS, FLS, CLS, CMP, CSDS has been in the restoration industry since 1978. Recipient of the 32nd RIA Martin L. King Award for his many contributions and sincere dedication to the Restoration Industry, and author of one of the industry’s leading technical resource book on the subject of structural restorative drying – Leadership in Restorative Drying. He is currently an IICRC Approved instructor of WRT, ASD and CDS certificate courses. Larsen is also an RIA instructor of the restoration industry’s advanced certification credentials: Water Loss Specialist (WLS), Fire Loss Specialist (FLS) and Certified Restorer (CR). He is also a Registered Third Party Evaluator® (RTPE). Ken lives in Florida and can be contacted at

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