Hardwood Flooring

By Kenn Garder, Corporate Accounts Manager, NPI/GPI Corporate Office

Empty RoomHardwood flooring has been used for years; the flooring, if properly maintained, can last the lifetime of the building.  The most common issues with hardwood flooring stem from moisture.  Wood is a natural product and is considered hygroscopic; It gains and loses moisture as the relative humidity and temperature of the air around it changes.

To minimize moisture issues the hardwood floor manufacturer usually dries the lumber so it has a moisture content of 6 to 9 percent before milling into the flooring.  The flooring should not be installed in rooms that are exposed to high moisture.  It is recommended that the flooring be delivered to the site of installation and allowed to acclimate for up to 4 days in an area that has been climate controlled for at least 48 hours and the sub floor is dry.  Following these recommendations is important to help minimize the amount of movement, but it’s not a guarantee that there won’t be issues caused by the changes in relative humidity.

Months and sometimes years after the floor has been installed and finished, moisture can still cause some visible issues.

Cracks and separation:  When the room is heated in the winter the relative humidity decreases, shrinking the wood. This can cause the wood to separate resulting in cracks.  To minimize these cracks moisture can be added to the air during the heating months.

Cupping:  Wood flooring can cup or curl at the edges leaving the center lower, resulting in an uneven surface. The wood expands when the relative humidity is higher or if water is spilled on the wood’s surface and absorbed.  As the wood expands, compression can result as the boards are crushed together deforming the edge of the boards. Humidity control will help the floor dry out and improve over time.


Crowning:  This is the opposite of Cupping. The center of the board is higher than the edges.  Crowning can occur if the wood is left exposed to high humidity or water for an extended period of time.  Another cause is sanding a cupping floor before it is dry; as the cupped wood continues to dry the edges will shrink more than the center of the board.


Buckling:   Because of excessive moisture, the flooring pulls up from the sub floor, lifting several inches from the sub floor.  When the floor is flooded with water for an extended period of time, buckling can occur.  A floor that has buckled will probably require more than drying out, typically, after drying out sections of the floor will need to be evaluated to determine if repairs can be made.


When these conditions are present in a hard wood floor, determine the water or moisture source and control or stop the moisture exposure to the wood.  In hot humid weather using air conditioning and possibly a dehumidifier to control the relative humidity will help to reduce the movement in the floor.


Garder PhotoWith 10 years of experience in his current position, Kenn Garder is the central point of contact for NPI/GPI’s national accounts. He also provides technical support to our franchise owners/inspectors and teaches the commercial segment of our training program.

To find an NPI or GPI inspector in your area, click one of the links below:



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What You Should Know About Water Damage Restoration and Mold Remediation

Submitted by Dale and Tiffany Senkow, GPI Franchise Owners, Prince Albert, Saskatchewan

Mold-FloorWall_shutterstock_177235112Q. Who do you recommend when there’s a flood in part of my home, and do they have any rules to follow?

A. To answer this question, we turn to the Institute of Inspection Cleaning and Restoration Certification, or IICRC. Think of ANSI/IICRC S500 and BSR-IICRC S520 as the most important professional water damage restoration and mold remediation standards for the industry, respectively.

S500 and S520 set the standards within water damage restoration and mold remediation. When water is discovered in a basement and noticeable water is present, you want a water restoration technician (WRT) as a contractor. A WRT is a trained professional who must practice continuing education and has proper training for just these types of scenarios. Water must be dried and cleaned up as soon as possible to prevent water loss to the structure and building materials.

IICRC Categories of Water Damage
Water loss is categorized into four stages of damage, which are basically determined by the amount of water, and anything that may have absorbed the water is also taken into consideration.

Category 1
This is water that has originated from a source that does not pose substantial harmful to humans. It is also known as “clear water.”

Category 2
This is best described as water containing a significant amount of chemical, biological and/or physical contamination. There is a risk of causing potential harm and discomfort. It can also cause sickness if consumed by or exposed to humans. It is referred to as “grey water.”

Category 3
This is grossly unsanitary water, containing pathogenic agents arising from sewage, or other contaminated water sources. It has the likelihood of causing discomfort and/or sickness if consumed by or exposed to humans. It is also referred to as “black water.”

Category 4 or Special Situations
These are situations that require other professionals, such as for the following:

  • Arsenic
  • Asbestos
  • Caustic chemicals
  • Fuels
  • Fertilizer
  • Glycol
  • Lead
  • Mercury
  • Mold
  • Pesticides
  • Polychlorinated biphenyls (PCBs)
  • Radiological residues and solvents

IICRC Classes of Water Loss
Senkow1In the photograph at the right, we can see an interior weeping tile system (often found on the exterior) that a contractor has installed. Along with waterproofing the exterior, this is a great method to capture water that has made its way underneath the wall, above the footing and into the building.

The S500 offers descriptions of four classes of water loss that designate environments by the relative degree of saturation, which is then used to determine the initial dehumidification equipment required to create an effective drying system.

Class 1 water loss is defined as the least amount of area, water absorption and evaporation. These water losses only affect a small part of the area or room containing materials that have absorbed minimal moisture. There is little or no carpet and/or cushion present.

Class 2 water loss is described as a large amount of water, absorption and evaporation. These water losses affect at least an entire room of carpet and cushion. Water has wicked up the walls less than 24 inches, which means you can physically see water saturation and the drywall. This class of water loss also sees moisture remaining in structure materials.

Senkow2Class 3 water loss is the greatest amount of water, saturation and absorption. The water may have come from overhead. The ceilings, walls, insulation, carpet, cushion and subfloor in the entire area are saturated.

Class 4 water loss is best described as a specialty drying situation. These are situations that consist of wet materials with very low permeation/porosity, such as brick, concrete, plaster, hardwood and ground soil. There are deep pockets of saturation that require a very low humidity ratio. These require longer drying times and special methods. For the WRT, this means high-temperature/high-performance devices — and more money. A very low vapor differential makes the area harder to dry.

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