Use of 5/16 Vs. 3/4 Hard Wood Floors

Application

• The 3/4-inch flooring must be sited over a wooden subfloor, typically constructed of plywood. The 3/4-inch boards are more susceptible to warping from water damage than their 5/16-inch-thick counterpart and should not be used in applications where repeated water exposure is likely, such as bathrooms. The 5/16-inch hardwood floors may be installed over wood or concrete subfloors, which means they can be utilized in applications directly over a concrete slab. Neither 3/4-inch nor 5/16-inch floors should be used for below-grade applications due to moisture concerns.

Installation

• The 3/4-inch hardwood flooring is typically manufactured with a tongue and groove profile. Each plank has one tongue side and one groove side running the length of the board. When two boards are placed against each other, the tongue and the groove align to stabilize the floor and hold the planks together. The 3/4-inch-thick hardwood floors are installed by driving nails at an angle through the tongue and into the subloor. The 5/16-inch flooring has the same tongue and groove profile as 3/4-inch, but it is attached to the subfloor using staples rather than nails.

Cost

• The 5/16-inch hardwood flooring will be less expensive than 3/4-inch flooring simply because less material is being used. Installation costs vary depending on the flooring application, but a 3/4-inch-thick floor will command a higher installation cost with a plywood subfloor than a 5/16-inch floor being installed on a concrete subfloor. The overall lifetime cost of a 3/4-inch floor will be lower than an equivalent 5/16-inch floor because it won’t require full replacement as soon as the 5/16-inch floor.

Wear Layer

• The major advantage of 3/4-inch-thick hardwood floor planks over 5/16-inch-thick planks is the longer lifespan. All hardwood floors have what is known as a “wear” layer. This is the thickness of the wood that can be removed during repeated refinishing processes. Once the wear layer has been consumed through repeated sanding cycles, the floor can no longer be refinished. A 3/4-inch-thick hardwood floor can be refinished repeatedly, and with proper care may last over 100 years. A 5/16-inch floor, on the other hand, is nearly 1/2 inch thinner than a 3/4-inch board and, therefore, will only withstand a few refinishing cycles before needing replacement.