Staples for Underlayment

Question

If I use staples for a Luan underlayment (for Linoleum in a bathroom), what size is best? Also, I thought the underlayment should end up half way through the doorway, but someone just told me only 3/4 inch and the carpet will be laid in the hallway and go through the doorway 4 inches.

Answer

If the underlayment is 1/4" or 3/8" the staples are 1 1/8" long and should extend at least 85% into the sub-floor, but not into the joists. These are chisel point narrow crown staples used with an 18 gauge air nailer. Otherwise use 1 1/4" ring nails. Keep the staples parallel to the grain so they won't splinter and will set themselves below the surface. I always check the floor after stapling with a 12" drywall knife and sliding it along the floor to see if it catches any staple heads that didn't go below the surface. A hammer blow will smarten it up.

The joint of different flooring is made under the door, in the center, so that from either side, when the door is closed, you only see the flooring in that room.

Dave