Originally Posted by Just Bill
Rosin paper is to isolate the layers and reduce squeaks. You could probably go right over the original subfloor, but if I were doing it, I would add a layer of 4-ply 1/2 CDX, glued and screwed. I hate callbacks.
I'm not worried about squeaks (the rest of the house is beautiful original birch hardwood, and squeaks like a pig!). To have one room sans-squeak would simply be out of character
. I'm more worried about misaligned planks, but i'll go over the joints with a palm sander.
Seriously though, i'm going to go around with 1.5" flooring screws and screw all the planks down, then test for squeaks. I already have 15# asphalt paper so I will use that instead of rosin. Hoping that will be sufficient for a good end-product.
If any squeaks arise after the fact, I'll fix them from below (unfinished)