Hello,

I have a 3/4 T&G subfloor on a webtruss crawl space. I have put down full moisture barrier in crawl space (Vaporblock 10). I have reinforced the subfloor with 2.5" screws on every panel. I will put down a 5/8 CDX plywood underlayment. My big question is about the fasteners recommended/preferred to secure the underlayment to the subfloor. I will secure the IndusParqet engineered hardwood to the underlayment with 18g 1.5" 1/4" narrow crown staples

Some installers recommended using 16g 1.5" adhesive coated staples to secure underlayment to subfloor, every 4-6" in the field and 3" on edges. Some others swear by 1.5" decking screws. The National Engineered wood association guide recommends ring shank nails. Now, I'm thoroughly confused

What is the best method to secure the underlayment to the subfloor? I will be putting down another layer of the same VaporBlock moisture barrier under the hardwood planks.

Thanks in advance
kd

Screws are great, staples are faster.