How Hardwood Flooring is Made

Not all hardwood flooring is created equal. Knowing the differences in how hardwood flooring is made can help you make an informed decision about what flooring will best fit you.

There are three commune types of hardwood flooring:

• Solid
• Engineered
• Acrylic Impregnated

Each type has advantages and disadvantages that should be considered before the installation.

Solid Wood Flooring

Solid wood floors are made of planks constructed from one piece of wood with tongue and groove edges. Planks can be delivered factory pre-finished or unfinished. Manufacture of the flooring starts with the tree itself. Trees are cut into logs and will be used to find out the quality of the tree. Trees marked for flooring are chosen for natural elegance with tight grain and few knots. Furthermore, the logs are cut into rough planks. There are different methods of cutting used. We present you the three most popular:

• Flat or Plain Sawn: are the most frequently used cut and it contains more variations than others.
• Quarter Sawn: cuts a log into quarters before it cuts the strips of wood to make hardwood flooring boards.
• Rift Sawn: cuts a log at a different angle than quarter sawn before it cuts the wood into hardwood flooring boards; even though it is more expensive than the other methods, it is also more stable.

The next step is grading the cut planks. After, the boards are planed on all four sides to smooth saw marks and level the plank.

A machine cuts the tongue and groove edges that make the boards fit together. Tongue and groove construction let’s on the boards to expand and contract, without creating gaps between planks in the installed floor. Smaller shops without a tongue and groove machine use a mounted router to mill the edges.

Now, the planks may go through a distressing process to give them an older, antique look. This may be accomplished by hand (hand scraping or hand sculpting) or by machine (wire brushing).

The final product is either sealed with several coats of protective finish or shipped unfinished to the marketplace. Pre-finished floors offer easier installation, especially for the DIY-er, but floors finished after installation offer a more impenetrable seal to moisture from above and a more uniform look. Solid hardwood flooring can be recycled from wood recovered and refinished from old wood, including sources like siding and floors once used in old factories, houses and barns and even from sunken boats or logs recovered from lakes and rivers. Reclaimed wood is often sawn into the familiar proportions of flooring, re-planed, and finished. Hand scraping to produce an authentic antique look is a popular used method.

The best advantage of choosing solid wood flooring is longevity. Solid wood floors can be restored to their original beauty by sanding and refinishing.

Engineered Wood Flooring

Engineered wood flooring is composed by gluing together a number of wood plies, with a veneer of real hardwood veneer glued on top. The plywood underneath the real hardwood veneer is the core board.

The plywood core board is constructed by stacking the plies one on top of another in opposite directions. After, they are glued together. By crossing the plies the finished planks are much more dimensionally stable than solid wood planks. This means they are much less likely to expand and contract the changes in temperature and humidity. This added dimensional stability means that engineered wood floors can be installed over concrete subfloors, over an in-floor radiant heating system and below grade. The more plies in the plywood, the more dimensionally stable the floor will be. Keep in mind that the more plies, the greater the cost.

Engineered wood floors are also made with core boards made from high density fiberboard, or HDF.

HDF is even more dimensionally stable than a plywood core board.

Three different ways of cutting the real hardwood veneer exist. The cutting method, along with thickness, has an impact on price.

• Dry solid-sawn: involves letting the wood dry out with a low humidity level to keep moisture from inside the wood cells intact, reducing the risk of cupping. It is the most expensive type of engineered flooring.
• Rotary-peel: involves boiling the log for a certain amount of time at a certain temperature to prepare the wood. The wood is scraped from the log with a blade working from the outside in and then pressed flat. It typically has a plywood-like grain and can have issues with cupping and warping to try to revert to its original shape.
• Sliced-peel: involves boiling the log for a certain amount of time at a certain temperature to prepare the wood. After the wood has been prepared, it is sliced from the end and then pressed to create a veneer.

Dry solid-sawn is the lowest yield for the highest cost, but has the best visual appeal, and strongest grain structure due to the sawing process. The grain pattern looks just solid hardwood.

Rotary Peeled provides the highest use of raw materials for the lowest cost, but has the lowest visual appeal and weakest grain structure. The grain pattern resembles plywood.

Sliced-peel provides better yield with medium cost, better visual appeal, and better structural integrity.

The higher the quality of the engineered flooring, the thicker the top veneer usually is. Veneer thicknesses range from 0.6mm to 6mm and can be made from any species of wood. The thicker the veneer the higher the price.

The edges of the layers are milled for tongue and groove construction or for a glueless click-lock system.

You must keep in mind that cheaper adhesives may emit unacceptable levels of formaldehyde. Engineered floors that are either E1 or E0 class or CARB-compliant are formaldehyde safe.

Some engineered planks will go through a distressing process such as hand scraping or wire brushing in order to have an old, antique look.

The product is now sealed with several coats of protective finish. Unfinished engineered wood flooring is also available.

Acrylic Impregnated Wood Flooring

For maximum wear, engineered hardwood flooring can be strengthen by forcing, or impregnating, the wood with stain and a liquid acrylic. This fills the cells and supports the wood structure. This category of flooring is extremely strong, resistant to impact damage. The stain is forced into the wood and the color goes all the way through the top layer. In conclusion, in worn spots will not appear different color, and areas exposed to the sun will not fade.

The wood is first placed in a vacuum to remove all the sugars and sap, leaving the cells dry and empty, resembling the cellular structure of cork. Methylmethacrylate(MMA) is a liquid acrylic, forced into the empty cells to replace the original sap. If the wood is to be stained, it is mixed with the acrylic before the impregnation. After it dries, the veneer is sanded and glued to the core material. The final product is sanded again and finished. This produces a surface up to 300% harder and more durable than natural wood.