I am replacing my entryway floor and I have removed the old mud bed. I'm left with planks perpendicular to the joists. However the room is defined at a 45 degrees angle from the joists, so the planks and the joists underneath them appear diagonal (it looks like an X).
I plan to install one layer of 3/4 inch plywood over the planks, and a layer of 1/2 inch plywood over the 3/4 inch plywood.
Along which direction should I install the plywood? If I install them along the directions of the room then they will be at a 45 degrees angle with the planks and the joist. I know that usually plywood are installed perpendicular to the joists but what about my case? Would this be ok?
When I screw the 1/2 inch plywood, should the deck screws only penetrate the planks or should they go through the planks and penetrate the joists as well?