I will be stapling 3/8 Engineered onto a Plywood subfloor on the 2nd floor (1st floor is a livable space (living room, dining room, etc. with climate control, not a basement).

Will a Rosin Paper underlayment good enough? I really don't want to risk using tar paper or roofing asphalt felt due to the kids asthma and allergies.


Thanks.

Some folks still use rosin paper, but it won't satisfy any manufacturer I know of if there's a warranty claim. Never made sense to me anyway when thousands of holes get punched into either one.

Follow the manufacturer specs. Aquabar may work better in your situation and many manufacturers mention it in their specs as an alternative to standard asphalt felt paper.