1. Introduction
The price of timber engineered flooring is largely affected by the lamella wood species and thickness. People tend to focus on the wood species with the best colour and texture from the perspective of aesthetic and economic efficiency when selecting engineered flooring while ignoring the thickness of the top layer lamella. In fact, compared to general engineered flooring, ultra-thick lamella engineered flooring has many irreplaceable advantages, one of which is that the ultra-thick top layer lamella can provide a more comfortable touch. This touch is difficult to quantify with physical parameters, but it is important to consider when choosing flooring.
2. What is the Flooring Touch?
In contrast to a concrete or tiled floor, timber engineered flooring deforms slightly and bounces back quickly when we step on it. This slight cushioning absorbs the kinetic impact, making it intuitively more comfortable to walk on. This is what we call “foot comfort”.
From physical parameters, this feeling is related to the hardness and stiffness of the flooring. The stiffness of the floor is mainly influenced by installation, i.e. the boundary conditions in material mechanics. At the same time, the hardness of the flooring is influenced by many other factors.
3. How Can I Get a Comfortable Touch?
3.1 Lamella Wood Species
Different top-layer lamella wood species provide timber engineered flooring with various hardness. There are many ways to characterize the hardness of wood, the most commonly used of which is Janka Hardness. This is obtained by measuring the maximum force of a fixed-diameter steel ball pressed into the wood. The Janka Hardness of the common wood species for flooring is shown in the table below:
| Wood Species | Gravity at 12% MC / (g/cm3) | Janka Hardness / N |
| Jatoba | 0.91 | 11950 |
| Bubinga | 0.89 | 10720 |
| Acacia | 0.84 | 10230 |
| Merbau | 0.82 | 7620 |
| Ash | 0.68 | 6580 |
| White Oak | 0.75 | 5990 |
| Teak | 0.66 | 4740 |
| Black walnut | 0.61 | 4490 |
| Tigerwood | 0.54 | 4180 |
| Birch | 0.62 | 4140 |
A lower hardness wood species as flooring top layer can bring the engineered flooring more foot comfort. However, a proper wood species is only a minor factor in the flooring’s foot comfort.
3.2 Lamella Thickness
For the flooring with the same wood species lamella, the flexible space of the thin top layer is relatively small, and the foot feeling is still hard and less comfortable. Flooring with ultra-thick lamella has enough elastic strain space in thickness, making each step have enough buffer. This can be interpreted figuratively as a mattress of the same material but a different thickness used for making a bed. A very thin mattress will make you feel much closer to a hard board when lying on it. In comparison, you can hardly feel the hard board when the mattress is thick enough.
However, it is not the case that the thicker the lamella is, the better the foot comfort it provides. When the thickness of the top layer reaches a certain degree, the elastic deformation produced on the footrest no longer propagates to a greater thickness. Generally speaking, the maximum lamella thickness is around 6 mm, and a thicker top lamella may cause several problems.
3.3 Installation Method
A layer of elastic backing material stuck on the back can effectively provide the flooring impact cushioning. In addition, another kind of installation is setting grids on the subfloor and then nailing the flooring on the grids. This method is commonly used in sports venues and dance studios, which can provide sufficient flexibility to the flooring.
4. Why Can’t I Measure and Assess this Touch?
Now that we know that the foot feel of the flooring is actually based on the physical parameters of hardness and stiffness, why is there no method to measure and assess it to help us select flooring?
In the current standard system, there are methods of measuring finish hardness and wood hardness. The finish hardness is an assessment of the ability of a painted surface to resist scratches from sharp objects. The wood hardness implies the ability of the surface of sufficiently thick wood to bear positive pressure. Neither can fully represent the ability to rebound from minor deformation when stepping on the flooring.
In the laboratory, it is difficult to quantify and assess the hardness and stiffness of different flooring in terms of measurement methods and usage environment stimulation. However, it does not mean there is no way to choose flooring with better foot comfort. By choosing the flooring with an ultra-thick lamella, the foot comfort of the engineered flooring will be much closer to that of the solid wood. Therefore, the thickness of the top layer lamella is the most important factor in the engineered flooring foot comfort.
5. Other Reasons for Choosing an Ultra-Thick Lamella
Here are two other reasons for choosing an ultra-thick lamella:
1. Engineered flooring with ultra-thick lamella can be refinished multiple times. For example, it takes about a 2mm-thick sanding allowance in each refinishing. Thus, the flooring with 6mm-thick lamella can be refinished twice. This engineered flooring is quite popular in Australia and Europe since it aligns with the current environmental protection concept of resource conservation.
2. A large bevel is feasible on ultra-thick lamella. Many customers prefer flooring with a larger bevel, which looks more stereoscopic and more pronounced. While the top layer below 2mm thick cannot make a large bevel on it. Ultra-thick lamella provides more bevel options.
