Getting to the core: Flooring Forensics - Feb 2018

By Lew Migliore

The rise of LVT/rigid LVT has, no doubt, put the screws on the laminate category. While laminate’s melamine face is highly scratch- and dent-resistant, the medium- density fiberboard (MDF) and high-density fiberboard (HDF) cores of the product can pose problems if utilized in the wrong setting. Educating yourself on the core board materials is key making sure that you’re choosing the right flooring for an application.

MDF-a product similar but denser than particle board-is used in variety of manufactured products, including furniture, cabinetry, doors and, of course, flooring. Wood fiber waste is mixed with binders and pressed into large sheets under heat. MDF doesn’t warp or swell easily, even under high humidity, making it an ideal core layer material for laminate. However, notice that I said “high humidity,” not water leakage, because water will affect almost anything. Just like particleboard, MDF will soak up liquids and swell. As such, using a product with an MDF core in an area that might be subject to water leakage, such as a kitchen or bathroom, could be problematic. Regardless of whether a manufacturer claims that water won’t affect the flooring, it’s best to err on the side of science here. Remember, it was water that carved the Grand Canyon.

MDF flooring is normally a value-engineered product, meaning it is a less expensive material, as it is made from waste. So you’ll frequently find this product used in multifamily structures where limiting cost plays a significant role.

HDF, also referred to as hardboard, is an engineered wood product. It’s made from wood fiber extracted from chips and pulped wood waste. As one might surmise, HDF is similar but much harder and denser than particleboard or MDF, making it an ideal stabilizing material for laminate floors. But just like MDF, HDF absorbs water. However, oil is sometimes added to the mix; through the high temperature and pressure manufacturing process, the oil becomes a polymer, creating a tempered form of hardboard. This hardens and strengthens the product and also makes it more capable of moisture resistance. It is now ready to be used in construction siding.

A user of either of these products must be aware of what they are capable of in terms of performance and what can compromise their performance. Many, if not all, MDF and HDF flooring types are tongue-and-groove click systems and, therefore, float. As with all floating floor installations, the substrate must be extremely smooth and level so the flooring on it will be as well. The presence of proud edges-the difference in height at the joints of planks-on the boards, often caused by core swelling, means the boards are susceptible to the top layer chipping, and may ultimately lead to replacement.

Often, MDF and HDF products are used in apartments. I was just called in to a project where the top layer of the laminate flooring was lifting and peeling off. Most surprisingly, no occupants were even in the building yet, as it was still under construction! At some point, a statement was made that the material was waterproof, yet when tested via immersion in water, the bottom layer peeled off, the core swelled, cracks formed, the top layer loosened, and the edge-where the tongue and groove are on either side-swelled. Had the building owner had a true grasp of the product being chosen, it’s likely that another selection would have been made. Don’t make the same mistake.

The laminate category is working hard to mediate these challenges via innovative bevel systems and edge technologies aiming to keep water on the top of the laminate floor surface, preventing it from penetrating to the core. In addition, some manufacturers are working on hybrid products that pair the durable face of laminate with the water resistant core of LVT/rigid LVT. As these trends progress, it is important to educate yourself and your customers about what, exactly, is at the core of each product in order to fully grasp the success rate for any particular application.