Wood flooring is any product manufactured from timber that is designed for use as flooring, either structural or aesthetic. Bamboo flooring is often considered a form of wood flooring, although it is made from a grass (bamboo) rather than a timber.
Solid hardwood floors are made of planks milled from a single piece of timber. Solid hardwood floors were originally used for structural purposes, being installed perpendicular to the wooden support beams of a building known as joists or bearers. With the increased use of concrete as a subfloor in some parts of the world engineered wood flooring has gained some popularity however in areas where homes traditionally have full basements solid wood floors are still common. Solid wood floors have a thicker wear surface and can be sanded and finished more times than an engineered wood floor. It is not uncommon for homes in New England, Eastern Canada and Europe which are several hundred years old to have the original solid wood floor still in use today.
Solid wood manufacturing
Solid wood flooring is milled from a single piece of timber that is kiln or air dried before sawing. Depending on the desired look of the floor, the timber can be cut in three ways: flat-sawn, quarter-sawn, and rift-sawn. The timber is cut to the desired dimensions and either packed unfinished for a site-finished installation or finished at the factory. The moisture content at time of manufacturing is carefully controlled to ensure the product doesn't warp during transport and storage.
There are a number of proprietary features for solid wood floors that are available. Many solid woods come with grooves cut into the back of the wood that run the length of each plank, often called 'absorption strips,' that are intended to reduce cupping. Solid wood floors are mostly manufactured 3/4" thick with a tongue-and-groove for installation.
Other wood manufacturing styles
This process involves treating the wood by boiling the log in water at a certain temperature for a certain amount of time. After preparation, the wood is peeled by a blade starting from the outside of the log and working toward the center, thus creating a wood veneer. The veneer is then pressed flat with high pressure. This style of manufacturing tends to have problems with the wood cupping or curling back to its original shape. Rotary-peeled engineered hardwoods tend to have a plywood appearance in the grain.
This process begins with the same treatment process that the rotary peel method uses. However, instead of being sliced in a rotary fashion, with this technique the wood is sliced from the end of a log, resulting in disc shaped veneers. The veneers then go through the same manufacturing process as rotary peeled veneers. Engineered hardwood produced this way tends to have fewer problems with "face checking", and also does not have the same plywood appearance in the grain. However, the planks can tend to have edge splintering and cracking due to the fact the veneers have been submersed in water and then pressed flat
Engineered wood flooring is composed of two or more layers of wood in the form of a plank. The top layer (lamella) is the wood that is visible when the flooring is installed and is adhered to the core. The increased stability of engineered wood is achieved by running each layer at a 90° angle to the layer above. This stability makes it a universal product that can be installed over all types of subfloors above, below or on grade. Engineered wood is the most common type of wood flooring used globally.
There are several different categories of engineered wood flooring:
All timber wood floors are made from sawn wood and are the most common category of engineered wood flooring. They do not use rotary peeled veneer, composite wood (such as HDF), or plastic in their construction.
Veneer floors use a thin layer of wood with over a core that is commonly a composite wood product.
Acrylic impregnated wood flooring uses a layer of wood that is impregnated with liquid acrylic then hardened using a proprietary process.
Laminate and vinyl floors are often confused with engineered wood floors, but are not—laminate uses an image of wood on its surface, while vinyl flooring is plastic formed to look like wood.
A bamboo floor is a type of flooring manufactured from the bamboo plant. The majority of today's bamboo flooring products originate in China and other portions of Asia. Moso bamboo is the species most commonly used for flooring.
Bamboo has been used as an alternative for flooring because of its physical similarities to true hardwoods. Bamboo floor manufacturers and sellers promote its strength and durability as well as its resistance to insects and moisture, and they say the material is also "eco friendly". The hardness of traditional bamboo flooring ranges from 1180 (carbonized horizontal) to around 1380 (natural), while newer manufacturing techniques including strand woven bamboo flooring range from 3000 to over 5000 using the Janka hardness test. Other flooring materials have comparable Janka ratings, with a higher number indicating a harder material: red oak (1290); white oak (1360); rock maple (1450); hickory (1820); and Brazilian Cherry / Jatoba (2350).
Different forms of bamboo flooring exist. Each varies in its manufacturing process and differs largely based on economic viability and local preferences.
The most common form, particularly in southeast Asia, uses thin bamboo stems that are cut as flat as possible. They are cut to similar lengths and can be stained, varnished, or simply used as is. They are then nailed down to wooden beams or bigger pieces of bamboo stems. This form results in more space between each bamboo stem; flatness and tightness is not emphasized. This technique is usually used on stilted houses, resulting in better air circulation especially during the warmer summer months.
The manufactured bamboo flooring commonly found in North American markets is very highly processed. A Bamboo flooring is typically made by slicing mature bamboo poles or culms into strips. These culms are crosscut to length and then sliced into strips depending on the width desired. The outer skin and nodes are removed. To remove starch and sugars the strips of bamboo are boiled in a solution of boric acid or lime. The bamboo is then dried and planed. Natural bamboo color is similar to beech wood. If a darker color similar to oak is desired, the bamboo goes through a carbonizing process of steaming under controlled pressure and heat. The carbonizing process can reduce the floor's final hardness significantly compared to non-carbonized bamboo, rendering it softer than some pines and softer than more common red oak.
Most bamboo flooring uses a urea-formaldehyde (UF) adhesive in the lamination process. Though the use of UF resins, which emit volatile organic compounds (VOCs), is harmful to indoor air quality, bamboo flooring uses a relatively small amount compared with other materials, such as particleboards. Bamboo flooring products that avoid formaldehyde use are available, including some listed in the GreenSpec Directory. The panels are then heat pressed to cure the adhesive. The cured boards are then planed, sanded, and milled. Finally an ultraviolet curing lacquer is applied to the boards.
Manufactured bamboo floors are typically made available in planks with either vertical- or horizontal-grain orientation. In vertical bamboo floors, the component pieces are stood vertically on their narrowest edge and then press laminated side to side. The effect is a lined, almost uniform look to the surface of the finished floor plank. In horizontal bamboo floors, the slats are arranged in a horizontal direction, on their widest edge, and then joined side by side with adjacent pieces using a high-pressure laminate system. The characteristic nodes of the bamboo are visible on the finished horizontal surface.
Locking bamboo flooring is the easiest to install. Individual flooring planks have interlocking joints that click precisely into place. By combining plank alignment and color a lot of different styles can be produced.