How to Glue Down Plywood Underlayment

1. 3/4 inch plywood underlayment

2. 15 lb (or higher) felt paper or rosin paper

3. Wood screws

4. Saw

5. Drill

6. Measuring tape

7. Level

8. Carpenter's pencil

9. Utility knife

10. Adhesive or nails

Step 1: Preparing the subfloor

Make sure the subfloor is clean and dry. Remove any nails, screws, or other objects sticking out of the subfloor. Verify the subfloor is level. If not, you may need to level using a self-leveling compound.

Step 2: Cut underlayment pieces to size

Measure and cut the plywood underlayment to the desired size. Each piece should cover the entire subfloor, with at least 3/4 inch of overlap on all sides.

Step 3: Install the felt paper

Install 15# felt paper or rosin paper over the subfloor. Felt paper will help to provide a moisture barrier and sound deadening between the subfloor and underlayment. Overlap the felt paper at least 3 inches and tape the joints together.

Step 4: Apply the adhesive

Apply adhesive to the back of the plywood underlayment. Use a trowel to spread the adhesive evenly and follow the manufacturer's instructions for proper application.

Step 5: Lay underlayment sheets

Place the underlayment sheets over the adhesive ensuring a minimum 3/4-inch overlap between each sheet. Press down firmly to ensure good adhesion.

Step 6: Secure with screws

Drill pilot holes and secure the underlayment sheets to the subfloor using nails or screws 8-10 inches apart along the edges and a row of screws down the middle.

Step 7: Check for level again

Double check the finished underlayment is still level. If not, use a leveler or sander to make adjustments.