When considering the type of wood flooring you want to use, the specific application may dictate your options to some degree. However, if engineered flooring is among your options, the installation location possibilities are greater.
For example, solid wood flooring is not recommended for use in “below grade” applications, but engineered wood flooring can often be successfully used below grade. Below grade means the floor surface is below the level of the ground outside, such as in a basement. Solid wood flooring is not generally recommended for use below grade because the typically higher moisture levels may cause problems with excessive expansion of the floor boards. Basically, the flooring may swell too much after installation and therefore not lay flat. When wood flooring expands (or wood in general – boards, wood siding, etc), it expands more in width than in length, so the result of solid wood flooring installed below grade can be buckling – sometimes enough that it can push some flooring boards right up off the floor!
Engineered flooring often can be successfully used below grade because it is considerably more stable than solid wood flooring thanks to its multi-ply substrate. It still should not be used in a very high moisture situation (no wood flooring product should be), but it definitely gives you additional installation location possibilities that you might not have with solid wood flooring.
Additional installation location possibilities offered by the use of engineered wood flooring are any location where there are very large swings in humidity. Think about a home in Northern climates that heats with a wood stove in the winter, creating a very dry environment in the home, then in the summer has the doors and windows open during a period of warm, humid, muggy weather. This is an ideal application for engineered wood flooring because the seasonal changes in humidity (severe in this example) would be problematic for solid wood flooring, but tolerated far better by engineered wood flooring, thanks to its superior dimensional stability.
Engineered flooring, due to the way it is manufactured, offers superior dimensional stability. It is more stable than its traditional counterpart, “solid” wood flooring. If you are unfamiliar with the construction of engineered wood flooring, it is essentially manufactured in a manner similar to plywood. The plywood base, or “substrate,” is made of thin layers of wood which are oriented with their grain in an alternating arrangement (90 degrees for each subsequent layer, or “ply”), and glued under heat and pressure. This creates a very stable wood flooring product, less susceptible to movement that could present itself as gaps between flooring boards, cupping, or crowning.
This highly stable base, when bonded to the top layer, or “wear layer” (what you walk on and see after installation), is what makes engineered wood flooring more resistant to the normal movement that occurs in wood flooring during changes in the relative humidity within the structure.
Many homes and commercial buildings undergo significant seasonal variations in relative humidity. In some parts of the United States the relative humidity within a building could range from 10% in the winter to 90% in the summer, depending on whether humidification is used during the heating months, and whether air conditioning (which dehumidifies the air) is used in the summer months.
All wood “moves” to a certain degree with these changes in relative humidity, and engineered wood flooring simply moves less than solid wood flooring because of the superior dimensional stability of the multi-ply substrate. Today there are a myriad of choices in engineered flooring in both exotic and domestic species, in both prefinished as well as unfinished engineered wood flooring. For many installation scenarios the superior dimensional stability of engineered wood flooring is worth considering.
There are three primary types of veneers, also known as “wear layers,” that are used in the construction of engineered flooring. These are:
1. Sawn veneers.
2. Peeled veneers.
3. Sliced veneers.
Each veneer type has its benefits and drawbacks that are important to consider when choosing material for your engineered floor.
Peeled veneers are made by first boiling and steaming a log. The log is then rotated against a blade that peels a layer off the log, which becomes the peeled veneer. Peeled veneers are typically the poorest quality of veneers.
Sliced veneers are considered to be superior to peeled veneers, though both process begin by boiling and steaming the log. Whereas the peeling method rotates the whole log against a blade, sliced veneers are made by slicing a quartersawn log either perpendicularly to the grain or radially by rotating the quartersawn log.
Sawn veneers are the oldest style of veneer, and are produced by cutting the log with a band saw. They are typically less dimensionally stable than sawn and sliced veneers, as they are more structurally similar to the actual log itself than the other two veneers. As a result, you can expect more swelling and contraction in an engineered floor with sawn veneers than one with sliced and sawn veneers.
Typically the thicker veneer types, usually sliced and sawn, will last longer as they can be refinished more often than thinner types. Thickness and method of construction are all important considerations for an engineered floor.