More in Floors
The floor needs to be as smooth and clean as possible to prep for the underlayment. Pull up every staple.
Lay out full sheets of underlayment. Use the underlayment with a pre-marked stapling schedule so you get the recommended number of staples.
Mark the areas that need cutouts and use a jigsaw to make the cuts.
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.
Secure the underlayment with a pneumatic stapler, using 1-3/8" 1/4" crown staples to penetrate into subfloor by at least an inch.
Pound down the staples with a hammer.
Note: Protruding staples will show through the vinyl flooring.
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.