Plywood Subfloor Preparation Services

Plywood underlayment is a thin plywood material that is most commonly used under resilient flooring materials, such as vinyl and linoleum sheets and tiles. It can also be used under hardwood, laminate, and carpet, but this is much less common these days because subflooring is typically smooth enough for these materials, many of which are installed with a different type of underlayment or pad.

Plywood underlayment provides a smooth, flat surface, without voids from knots or other surface imperfections common with subflooring.

When to Use Plywood Underlayment

A properly installed plywood subfloor provides a suitable installation surface for most flooring materials, including luxury vinyl planks (LVP), which are thicker than traditional vinyl tiles and can smooth over slight imperfections better. Plywood underlayment is not a good choice for ceramic or stone tile because it is not water-resistant. For floor tile in any room, use cementboard or a similar tile backer instead.

Types of Plywood Underlayment

Most plywood underlayment is about 1/4 inch thick and has square edges and a smooth, knot-free top face. It typically comes in 4 x 8-foot sheets. For many years, the standard option was lauan plywood, also called Philippine mahogany or luan plywood, Today, a much better option is plywood specifically designed as underlayment and made with sustainably forested wood. You can also use AC exterior-grade plywood, which has one smooth face and one rougher face.

Installing Plywood Underlayment

The installation process starts with storing the underlayment panels in the room where they will be installed for at least 72 hours. This acclimates the panels to minimize expansion/contraction issues after installation. Once the subfloor is thoroughly cleaned, the underlayment panels are installed one at a time directly over the subfloor. The underlayment sheets usually run the same direction as the plywood subflooring, but it is critical that the seams of the underlayment are offset from those in the subflooring, so the underlayment bridges over the subfloor joints.