Types of Hardwood Flooring Construction

Solid Hardwood

Solid hardwood is ¾” thick and is made of the selected species of wood throughout the thickness of the board. The only installation method acceptable for solid hardwood is to nail it to the subfloor which means it can only be installed over plywood or OSB subfloors. It can’t be installed below grade or over concrete subfloors. Solid hardwood has the advantage of being able to be refinished multiple times if needed.

Engineered Hardwood

Engineered hardwood is composed of several layers of wood that are glued together to give it stability and rigidity in a thinner profile than solid hardwood. This stability gives it the advantage of not being required to nail it to the subfloor for installation. Instead, it can be glued or floated over a variety subfloors including concrete, so it can be installed below grade. Usually, only the top layer of engineered hardwood is the selected species of wood. Engineered hardwood can’t be refinished as many times as solid hardwood can, if at all.

Hardwood Widths

Hardwood flooring widths fall into two categories. Strip flooring comes in widths ranging from 1 ½ inches wide to 3 inches. Plank flooring, on the other hand, comes in widths of at least 3 inches in width.

Hardwood Species

Hardwood flooring comes in a wide array of different species. Each species of wood has its own characteristics. Among the most significant characteristics are hardness, color, color stability, and grain pattern. Hardness is measured by means of the Janka hardness test. The test measures the amount of force necessary to embed an 11.28 mm steel ball into a given species of wood to half of the steel ball's diameter. The following chart shows the hardness values of a variety of wood species as determined by the Janka hardness test.


Janka Hardness Scale for Hardwood Floors