Pass the IICRC Restoration WRT Questions and answers with CertsForce

The IICRC WRT body of knowledge provides initial LGR dehumidification recommendations based oncubic footage and class of water. ForClass 3 water intrusions, a commonly taught starting guideline is approximatelyone LGR dehumidifier (≈100–150 PPD) per 3,000 cubic feetof affected space.

In this scenario, the drying chamber volume is 7,500 cubic feet. Dividing 7,500 by 3,000 yields 2.5 units. Because dehumidifiers cannot be fractionally deployed and WRT guidance supports roundingupto ensure adequate moisture removal, the initial recommendation isthree LGR dehumidifiers.

The WRT manual emphasizes that this is an initial placement subject to adjustment after monitoring confirms drying progress. Insufficient dehumidification can increase ambient humidity, slow drying, and elevate secondary damage risk—particularly in Class 3 losses where evaporation rates are high.

Placing three units provides adequate capacity to manage evaporated moisture while allowing later downsizing as drying goals are achieved.

The IICRC WRT body of knowledge states thatdesiccant dehumidifiersare the most effective option when ambient temperatures fall below approximately50°F. Refrigerant-based dehumidifiers rely on condensation at cold coils and become inefficient or inoperative at lower temperatures due to coil icing and reduced moisture removal capacity.

Desiccant systems remove moisture throughadsorption, a chemical bonding process that is not dependent on air temperature. This allows desiccants to perform effectively in cold environments where refrigerant units fail.

The WRT manual highlights desiccants as the preferred solution for cold structures, unheated buildings, winter losses, and Class 4 drying scenarios. Gas bypass and LGR units extend the operating range of refrigerants but still have temperature limitations.

Selecting the correct dehumidifier type based on ambient conditions is a core competency under the WRT standard and ensures efficient, defensible drying.

The IICRC WRT body of knowledge explains thatsheet vinyl flooring acts as a vapor barrier, significantly restricting moisture vapor movement from the subfloor beneath it. Because evaporation is inhibited, subflooring beneath vinyl cannot be effectively dried while the covering remains intact.

As a result, the WRT manual states that the most effective and reliable method is toremove and discard the vinyl flooringto allow direct access for drying. This enables airflow, temperature control, and dehumidification to act directly on the wet subfloor.

Perforating vinyl is unreliable and may cause additional damage without ensuring adequate vapor release. Placing an air mover at an edge does not overcome the vapor barrier effect. Simply adding equipment without removing the barrier does not resolve the drying limitation.

Removing vinyl aligns with the WRT principle that vapor barriers must be addressed to achieve effective drying and prevent hidden moisture from causing secondary damage.

The IICRC WRT body of knowledge states that moisture detection instruments allow restorers to evaluate and documentpsychrometric conditions and moisture content or moisture level readings. These measurements form the foundation of drying verification and defensible documentation.

Moisture meters measure moisture within materials, while thermo-hygrometers capture air temperature and relative humidity, enabling calculation of dew point, humidity ratio, and vapor pressure. Together, these tools allow restorers to assess drying effectiveness, establish drying goals, and demonstrate progress over time.

Thermal imaging provides indirect information and must be verified, while manometers and particulate counters serve specialized purposes outside routine moisture documentation.

The WRT manual emphasizes consistent measurement, proper instrument selection, and clear documentation as essential components of professional restoration practice and project closeout.

The IICRC WRT body of knowledge clearly states that a restorer must inspectall potentially affected areasin a water-damaged structure. Water migration is often hidden and does not always follow visible or obvious paths. Gravity, capillary action, air movement, and building assemblies can allow water to spread far beyond the area initially identified by occupants.

The WRT manual emphasizes that relying solely on visible water, odors, or customer statements is insufficient and can result in missed moisture, incomplete drying, and secondary damage. Hidden moisture may exist behind walls, under flooring, inside cabinets, beneath insulation, or in adjacent rooms not immediately associated with the loss.

A comprehensive inspection includes visual assessment, moisture detection instruments, infrared imaging (verified with meters), and evaluation of building construction features that may facilitate water movement. This approach ensures accurate scoping, proper classification, and effective drying system design.

Inspecting all potentially affected areas aligns with the ANSI/IICRC S500 Standard’s requirement for thorough evaluation and defensible documentation, reducing the risk of undiscovered moisture and future claims.

The IICRC WRT body of knowledge stresses thatdocumentation is a critical component of professional water damage restoration, and restorers are expected to obtain and maintain documents that validate drying progress and project completion. These records demonstrate that drying goals were properly established, monitored, and achieved in accordance with the ANSI/IICRC S500 Standard.

Drying documentation typically includes moisture content or moisture level readings, moisture maps, psychrometric data (temperature, relative humidity, humidity ratio, and dew point), equipment placement records, and daily monitoring logs. Together, these documents form a defensible record that shows the restorer followed an appropriate standard of care.

The WRT manual explains that such documentation is necessary not only for communication with materially interested parties (owners, occupants, insurers) but also for dispute resolution, quality assurance, and potential legal proceedings. Without validated drying documentation, it is difficult to prove that materials were returned to a dry standard or that secondary damage was prevented.

AHAM certificates may be useful for understanding equipment performance, but they are not required project documents. Law enforcement permission and historical restoration records are unrelated to the drying verification process. Therefore, obtaining documents that validate drying and completion is the correct and required practice under WRT guidance.

The IICRC WRT body of knowledge identifieshygroscopic materialsas the most susceptible to secondary damage caused by elevated humidity. Hygroscopic materials readily absorb and release moisture from the surrounding air until they reach equilibrium with ambient relative humidity. Common examples include wood, paper, drywall, textiles, and many composite building materials.

The WRT manual explains that when relative humidity rises—particularly above safe thresholds—hygroscopic materials absorb moisture even without direct water contact. This can lead to swelling, warping, loss of structural integrity, finish failure, corrosion of fasteners, and increased microbial risk. This process is known assecondary damage, because it occurs after the initial water intrusion and is driven by uncontrolled environmental conditions.

Unabsorbent, hydrophobic, and non-porous materials resist moisture absorption and are far less affected by high humidity alone. While condensation may occur on these surfaces, they do not readily absorb moisture into their structure.

Because of this behavior, the WRT curriculum emphasizes aggressive humidity control during drying—not only to dry wet materials but also to protect unaffected hygroscopic materials within the drying chamber. Monitoring relative humidity and vapor pressure is therefore essential to prevent secondary damage.

The IICRC WRT body of knowledge requires that restorersrecord and monitor drying measurements at least daily. Daily monitoring ensures that drying systems are functioning properly, drying goals are being approached, and adjustments can be made promptly if progress stalls.

Measurements typically include air temperature, relative humidity, humidity ratio, dew point, and moisture content or moisture levels of affected materials. The WRT manual emphasizes trend analysis—comparing daily readings to confirm consistent moisture reduction.

Infrequent monitoring increases the risk of unnoticed equipment failure, elevated humidity, condensation, or secondary damage. Weekly or bi-weekly monitoring does not meet the professional standard of care outlined in the ANSI/IICRC S500 Standard.

Daily documentation also supports defensibility by demonstrating continuous oversight and proactive management of the drying process. It provides transparency to materially interested parties and ensures accountability throughout the project lifecycle.

The IICRC WRT body of knowledge identifiesrelative humidity at or above approximately 70%as presenting the greatest risk for structural and microbial damage to hygroscopic materials. At this level, many materials readily absorb moisture from the air, increasing moisture content even without direct liquid water contact.

The WRT manual explains that hygroscopic materials such as wood, paper, drywall, and textiles reach higher equilibrium moisture contents as RH increases. When RH exceeds safe thresholds, these materials may swell, deform, lose structural integrity, or support microbial growth.

Microbial amplification risk also increases significantly at higher RH levels. While mold growth depends on multiple factors, sustained RH above approximately 60–70% greatly increases the likelihood of microbial activity on organic materials.

This is why restorers are trained to aggressively control humidity during drying and to monitor RH as part of daily documentation. Maintaining RH well below damaging thresholds protects unaffected materials and limits secondary damage during the restoration process.

The IICRC WRT body of knowledge states thatcarpet cushion (pad, underlay) must be removed and discarded when affected by Category 2 or Category 3 water. Carpet cushion is a porous material that readily absorbs and retains contaminants, making effective cleaning and decontamination impractical under these conditions.

The WRT manual explains that even if the overlying carpet may be cleanable in some situations, cushion acts like a sponge and can harbor microorganisms, nutrients, and moisture deep within its structure. Attempting to dry or disinfect contaminated cushion poses a health risk and increases the likelihood of secondary damage or odor problems.

While certain cushion types (such as synthetic felt or cushions with skins) influence restorability in Category 1 losses, contamination level takes precedence. The presence of Category 2 or 3 water alone is sufficient to require removal, regardless of cushion construction or subfloor type.

This guidance reflects the WRT emphasis on protecting occupant health and preventing hidden contamination. Removing and discarding contaminated cushion is considered the appropriate and defensible standard of care.