How to Install Underlayment for Hardwood Floors

Underlayment is the silent partner of every great hardwood floor. It acts as a moisture barrier, a sound dampener, and a critical leveling agent that keeps your planks from feeling hollow or clicking underfoot. Without it, you are essentially asking your finish floor to survive the structural shifts of your subfloor unsupported. Installing this layer is the most satisfying step in a flooring project because it is fast, quiet, and instantly makes your subfloor look finished. The goal here is a seamless, flat surface that covers every inch of the room without bunching or overlapping. When you do this right, the installation of your hardwood goes twice as fast.

1. Clear Every Speck First. Clear the room of all debris, staples, and protruding nails. Vacuum the entire surface thoroughly to ensure no grit remains, as any trapped debris will create ticking sounds under your new floor.
2. Position Your Starting Strip. Start in the corner farthest from your exit. Lay the first strip of underlayment parallel to the wall you plan to start your flooring installation against.
3. Unroll Tight and Flat. Unroll the underlayment across the room, keeping it flat and taut. Ensure the edges meet perfectly without overlapping, unless your specific product requires an overlap seam.
4. Sharp Blade, Perfect Gaps. Use a sharp utility knife to trim the underlayment along the walls. Leave a consistent gap of about 1/4 inch to account for house movement.
5. Seal Every Seam Tight. Apply a high-quality flooring tape over every seam where the underlayment strips meet. Ensure there are no gaps, as this prevents moisture from rising from the subfloor into your wood.
6. Verify a Perfect Finish. Walk over the entire surface to check for air bubbles or loose areas. Re-tape any sections that have lifted and ensure the material is pinned flat.