Applied Structural Drying (ASD)
Advanced IICRC certification for efficient, science-based drying of water-damaged buildings and contents.
What is Applied Structural Drying?
Applied Structural Drying (ASD) is an advanced methodology and IICRC certification focused on the efficient, effective, and timely drying of water-damaged buildings and contents.
It builds on basic water restoration principles by emphasizing scientific, psychrometry-based techniques to minimize demolition, reduce drying time, and prevent secondary damage like mold growth.
ASD shifts the approach from "rip-out and replace" to "dry in place" where possible, using science to accelerate evaporation while controlling humidity—ideal for complex losses and North Bay homes facing floods or leaks.
The IICRC ASD Certification
The Applied Structural Drying Technician (ASD) certification from the IICRC is an intermediate/advanced credential for water damage restorers.
Prerequisites
Must hold the Water Damage Restoration Technician (WRT) certification first. WRT knowledge of psychrometry and basic drying is essential.
Course Structure
Typically 3 days (21 hours) of instruction, plus exam time. Combines classroom theory with extensive hands-on training—often in a "flood house" where students set up equipment, monitor drying, and apply techniques.
Exam Details
Multiple-choice test (~110-160 questions, passing ~75%). Fee: ~$80 paid to IICRC. Retakes available.
Maintenance
14 Continuing Education Credits (CECs) every 4 years; small annual renewal fee.
Key Topics Covered
- Advanced Psychrometry: Calculating evaporation rates and dehumidification needs
- Specialized Equipment: Injectidry systems, TES drying, mat systems
- Hard-to-Reach Drying: Walls, cavities, hardwood floors, subfloors
- Safety & Documentation: Health considerations and proper record-keeping
- Decision-Making: In-place vs. disruptive drying strategies
Core ASD Techniques
Psychrometry-Driven Planning
Use psychrometric charts/calculators to balance temperature, humidity, and airflow for optimal evaporation. Goal: Create an environment where air can absorb moisture rapidly from materials.
Aggressive Water Extraction
Thorough initial extraction (truck-mounts, portable extractors) to remove free water before drying begins.
Directed Airflow & Heat
High-velocity air movers create turbulence to disrupt boundary layers on wet surfaces. Heaters raise temperature to increase evaporation potential.
Advanced Dehumidification
Refrigerant, desiccant, or LGR (low-grain refrigerant) dehumidifiers remove moisture from air. Balanced systems prevent over-drying or secondary humidity spikes.
Class 4 Losses: Where ASD Training Proves Its Worth
Under the ANSI/IICRC S500 standard, a Class 4 water intrusion involves deeply held or bound water in low-permeance materials — hardwood flooring, plaster, concrete, masonry, and other dense assemblies that release moisture slowly. These losses cannot be dried with air movers and standard dehumidification alone; they require longer drying times, specialty equipment, and precise psychrometric control to create the vapor pressure differentials that pull bound moisture out of dense materials.
ASD-certified technicians are trained to calculate drying goals from a dry standard, select between refrigerant, LGR, and desiccant dehumidification for the conditions at hand, and document daily readings until goals are verified. In the North Bay this expertise matters for older plaster homes in Petaluma and Napa, hardwood floors throughout Santa Rosa, and concrete slab construction across Marin — exactly the materials where guesswork leads to cupped floors, delamination, and hidden mold.
Specialized In-Place Drying Methods
Injected Drying
Systems like Injectidry force air into wall cavities, under cabinets, or hardwood floors.
TES (Thermal Energy Systems)
Controlled heat + ventilation for rapid drying of structures.
Mat Systems
Specialized drying for glued-down carpet or vinyl flooring.
Floor Drying
Venting or drilling techniques for subfloor moisture removal.
Why Pursue ASD?
- Required for Master Water Restorer designation
- Enhances credibility with insurance companies
- Qualifies for advanced restoration jobs
- Proves proficiency per ANSI/IICRC S500 standard
ASD Benefits
- Reduces demolition costs
- Speeds occupancy return
- Minimizes disruption
- Prevents mold growth