Panelization and Sidebonding

Sidebonding typically occurs when certain waterborne finishes or sealers flow between the sides of boards and glues them together. When several boards are bonded together they form into one large slab or “panel” of wood. This is referred to as panelization.

Panelization has been seen with several types of finishes, but is most prominent with waterbornes. Their high strength causes these products to act as particularly strong glue. These products also have very low viscosities, making it easier for them to flow into and through cracks.

As the humidity of the environment fluctuates, the wood will expand and contract in response to changes in its moisture content. Humidity fluctuations of 15% or more can cause substantial movement in the gymnasium floor. Normally, this movement is distributed over hundreds of cracks between individual boards. However, when several boards are panelized together, they leave larger-than-normal cracks at random spaces across the floor. The bond between boards is so strong that movement of the wood might cause a split right down the center of the board, rather than on the edges. Typically this occurs on gymnasium floors.  The floor itself can also be glued to the concrete subfloor, making movement impossible.

To minimize damage to your wood floor from panelization, be sure to:

  • Control Temperature & Humidity
    Often overlooked, controlling humidity fluctuations is undoubtedly the most direct way to control panelization by minimizing wood movement. All year long, humidity inside a facility should be maintained between 40% – 60%., and temperature should be kept between 65°F – 75°F.
  • Select the Proper Coating System
    With increasingly stringent VOC regulations, contractors are more frequently using waterborne finishes. Until recently, the use of waterborne sealers was not recommended for new floor installations.  The risk of panelization was just too great.

PoloPlaz has now developed NSB waterborne sealer which was specifically designed to eliminate damage to the wood floor as a result of panelization.  When used properly, NSB can be successfully applied on new floors and then top coated with a high-strength waterborne finish.

If a total waterborne system is necessary (including a waterborne sealer), the owner should be warned about the possibility of panelization, and how to combat it by controlling humidity.

Dry vs. Cure

Drying occurs when solvents evaporate from the surface of the film, leaving it tack free. There are four important elements of proper drying: temperature, humidity, film thickness and airflow. Temperature affects viscosity, which contributes to film thickness. Humidity affects the evaporation rate of the solvents. The amount of airflow determines how much oxygen will crosslink with the finish to initiate curing. High temperatures, low humidity, thin film thickness and adequate airflow will all expedite dry time and cure time. If these elements are not maintained properly, the finish could dry too quickly.

Curing occurs when residual solvents leave the film and it begins crosslinking with oxygen in the air to develop strength, toughness, abrasion resistance and chemical resistance. Although most finishes reach 90% cure in seven days, full cure takes up to thirty days.

Gym Maintenance

Temperature and Humidity

Temperature should be kept between 55°F-75°F. Humidity level should be kept between 35%-50% to ensure minimal wood movement.

Routine Cleaning

Dry mop the floor daily to eliminate dust buildup. As needed, tack floor with PoloPlaz Hardwood Floor Cleaner to remove perspiration, oils, spills and residue from foot traffic. Do not use dust mop treatments or floor cleaners that contain wax, paraffin, silicone and mineral oil. Do not use pre-treated dust mops. Use of these products can cause adhesion problems when recoating the floor. Dirt, sand and grit will dull and accelerate the wear of the finish. Place floor mats or rugs at all entryways, bathroom exits or other high traffic areas to remove excessive dirt or moisture. Spills or liquids on the floor should be wiped up immediately.

Power Scrubbers

Never use power scrubbers or automatic floor cleaning machines that disperse water on the floor (especially water under pressure). The use of scrubber machines will void the warranty on your floor. Power scrubbers were designed for other surfaces, such as terrazzo and vinyl floors. Even the softest brushes will scratch and dull the finish. The chemicals typically used in these machines are too aggressive for wood and finishes. The machine’s liquid and scrubbing action can cup the floor, and pull paint and finish from the wood.

Floor Covers and Mats

Gym floor covers should never be used on a freshly finished floor until at least three weeks after the last coat of finish has been applied. For complete curing, the finish surface must be exposed to oxygen in the ambient air. Covering the floor during this process would deny the oxygen needed to complete this reaction, potentially resulting in a partially cured coating with poor physical properties. Also, it is imperative that the floor be cleaned before the cover is laid. Otherwise, any grit or dust on the floor will mar the floor when the cover is walked on or when any loads are moved on the floor. Covers should not be taped to the floors. The adhesive in most tapes will attack the finish and result in delamination.