Step 1: Smooth and Clean the Floor

The floor needs to be as smooth and clean as possible to prep for the underlayment. Pull up every staple.

Step 2: Lay Out the Underlayment

Lay out full sheets of underlayment. Use the underlayment with a pre-marked stapling schedule so you get the recommended number of staples.

Step 3: Make the Cuts

Mark the areas that need cutouts and use a jigsaw to make the cuts.

Step 4: Undercut the Doorjamb

For a professional look, the underlayment and flooring should fit under the doorjamb. Use a power jamb saw or a Japanese pull saw to undercut the doorjamb.

Step 5: Secure the Underlayment

Secure the underlayment with a pneumatic stapler, using 1-3/8" 1/4" crown staples to penetrate into subfloor by at least an inch.

Step 6: Hammer the Staples

Pound down the staples with a hammer.

Note: Protruding staples will show through the vinyl flooring.

Step 7: Fill the Seams

Fill all the seams with gypsum-based skim coat.

Step 8: Go Over the Seams

After about 15 minutes the gypsum skim coat will be dry. Go over the seams with an orbital sander, smoothing out the high points and feathering the edges.