Hi,
I'm doing my FIRST time flooring.
I don't have any experience.

So I have couple questions :


Icomming data:
- existing subfloor is OSB ( medium condition )
creak in some places. dry. almost flat.

- I bought PLYWOOD 3x8 (12.5 mm = 1/2 Inch ) shits to lay
it ower existing OSB floor.

- I have Maple fsc Portland 3 1/4 x 3/4 HardWood floor.

What I'm going to do:
( please correct me if I'm wrong )
1) screw down existing OSB floor to joint with floor screews 2" (to not have a creaks).
2) lay down PLYWOOD over OSB. Screew is down to OSB floor with floor screes 2".
3) put over a working paper don't remember (the brand)
4) put my HARDWOOD floor into the room for 72 hours to PRE ACCLIMATE.
5) Nail-down them by 18GA nails ? ( have doubt about this ). I have only 18 GA nail gun.
6) Finish and drink a beer over new floor.

Thanks

1- Sounds like a good plan. Keep it consistent.
2- Still sounds good. Hit the floor joists too, but I think that's what you're alluding to with 2" screws.
3- #15 felt or the popular aquabarB
4- It's not a time thing. It needs balanced moisture levels throughout the home, including the basement below.
5- Invest or rent a real hardwood stapler or cleat nailer
6- Just one beer?

Solid Maple? Spooky

OSB and 3/8" ply? Hard to tell w/o being there. Most OSB will be fine with 3/8" over it.