Four Degrees of Water Damage

You may have had a small roof or plumbing leak.  A bath tub overflow.  A ruptured water heater.  Or major storm flooding.

The amount of water is only part of the water-damage equation.  The potential for deterioration and the extent of drying measures also depend on the rate of soak-in, the duration of exposure, and the rate of evaporation.  And those in turn depend on the area and type of materials affected.

When moisture lingers for more than a day carpet, furniture, and building surfaces typically develop mold.  Soon drywall swells and crumbles, wood swells, warps, and splits.  Metals corrode.  And given time even concrete weakens.  So damage can range from minor discoloration all the way to structural problems.  With Christian Brothers the emphasis is on prevention and mitigation.  Problems can become significant within 24-72 hours, so our focus is on getting things significantly dryer if not completely dry within that time frame.

IICRC Classes of Water Damage

The ANSI/IICRC S500 Standard and Reference Guide for Professional Water Damage Restoration ( is the gold-standard for the cleaning and restoration industry.  It presents practical guidelines and procedures based on science and extensive experience.  We talked about their categories of health hazards and the needs for surface cleaning and disinfecting before.  Let’s now cover the degrees of leaks, spills, and water intrusions and their potential for damage.  The IICRC divides them into four “classes.”  It doesn’t giving any specific amounts of water as many other variables go into determining the proper water restoration measures.

Class 1

This class involves the least amount of water.  It’s defined as affecting only part of a single room, with minimal wet carpet and affecting only low-permeable materials such as plywood and concrete sub-flooring.  Resulting from things such a roof leak and rowdy kids in the bath tub, there’s minimal absorption and little moisture remaining after bulk water removal.  So after mopping and blotting a natural slow rate of evaporation may be acceptable.  Lifting carpet speeds drying and lets you determine if the sub-floor is excessively damp.

Class 2

Here there’s more water, and more gets absorbed by building materials.  It’s defined as affecting an entire room or resulting in large areas of wet carpet, with water wicking upwards in walls at least 1 foot (but less than 2 feet) and moisture reaching structural materials.  Class 2 water intrusions require bulk water removal, surface water extraction, and dehumidification for faster evaporation.

Class 3

With the most water and greatest absorption involved, Class 3 water restoration requires the fastest evaporation to head off deterioration.  It’s defined as having flooring, sub-flooring, walls, and insulation saturated.  With a source above the ceiling, that may be saturated as well.  Advanced drying and dehumification methods via specialized equipment are critical.

Class 4

This last class is a special situation, typically the result of heavy natural flooding.  There’s been enough water and time to saturate materials such as stone, concrete, brick, and hardwood.  Highly aggressive methods to maintain very low specific humidity for longer periods than usual are required.  Or the affected rooms may be considered a total loss if the structure has been severely compromised.

Professional Water Damage Restoration

Homeowners, business owners, and commercial carpet cleaning services can often take care of cleaning and restoration for Class 1 situations.  But if there’s any doubt, call in a professional water damage restoration company for an evaluation.  You just might avoid the need for mold remediation, or worse.

Otherwise the risks range from odors to major structural damage.  For Class 2 and beyond it’s common to discard carpet and padding, mattresses and box springs, pillows, and particle board.  But wood baseboards and hardwood floors can usually be rescued.

The IICRC’s water damage restoration training ( emphasizes the importance of locating and removing trapped moisture hidden inside building cavities using leak and moisture detection meters to make sure nothing gets overlooked.

Technicians with various cleaning and restoration certifications carefully evaluate damp and wet materials then plan out the appropriate measures. They’re also well aware of electrical hazards, health risks, and safety hazards. Beyond visible water removal, they’ll quickly lower indoor humidity and rescue floors, walls, and ceilings with surface water extraction before moving on to further dehumidification for a complete structural dry out.  That involves an arsenal of advanced equipment, including specialized air movers, HEPA air scrubbers, refrigerant dehumidifiers, and odor-neutralizing equipment.  There’s also specialty drying systems for hardwood floors, sub-floors, and wall interiors.