Tips for Installing Plywood Underlayment and New Flooring Over an Existing Floor

September 24th, 2014

Before beginning any new flooring project, you must check the existing floor or subfloor to ensure it is a sound, level, clean and solid structure before putting down a new floor. If you are having trouble determining the condition of the existing floor, you should hire a professional flooring contractor. A flooring contractor can test the flooring system to ensure that a new floor can be installed on top of the existing one.

In preparation for putting down plywood underlayment and a new floor, the following steps can be performed by any Do-It-Yourselfer (DIY):

Remove all furniture from the room or rooms where you plan to install new plywood underlayment and flooring.

  • Make sure all background noise is limited.
  • Slowly walk the floor, applying pressure by stepping down with force in various areas. Be sure to cover the entire room. Closely watch the floor where pressure is being applied, looking for any movement in the flooring system. If any movement is noticed, it could be an unsound subfloor or a floor joist that has worked loose over time. These problems must be investigated further and repaired before continuing.
  • Listen intently where pressure is being applied. You’ll want to listen for squeaks or crunching noises. If you hear either of these, you must investigate further and repair these areas before continuing.
  • Thoroughly clean the existing floor, making sure there is no debris or sticky spots on the surface. If you are installing plywood underlayment over existing sheet vinyl or vinyl tile, make sure there is no wax build-up on the vinyl. Wax build-up can trap dirt or debris and may prohibit a tight fit between the plywood underlayment and the subfloor. You can purchase a wax remover from your local home improvement store; be sure to follow the manufacturer’s directions on the package. You can also use a mixture of equal parts water and ammonia to remove any build-up.

Once these steps have been completed and you have determined that your existing floor is sound, level, and clean, you can proceed with the installation of the plywood underlayment. Check out our SurePly® Installation Video at

To learn more about the Patriot Timber family of panel products and our line of plywood underlayment panels, visit

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