I'm doing a bathroom job, and need to install marble floors. Tore out the old, saw significant water damage to the sub floor. Tore it all out, going to put new 23/32" ply for subfloor, quarter inch hardibacker cement board, then flexbond and the marble. Problem is with this subfloor, the bathroom is a 5 x 4 powder room, and the sub that was in there was part of sub from the hallway also. I'm not very experienced installing new sub, but I do know that I need this floor to be very sturdy so as to not have cracks or strain in the marble down the line. Now what I have here is like 4 joists to work on, and on the side with the doorway, I don't have a joist. I can't attach to it either, there is a duct in the way, would be difficult to move. As it is right now, if I installed the sub, the first 10 inches or so would have no support from a joist. Can I bridge a little side off the closest joist? Ideal would be to hook up to the joist under the hallway floor, but vent is in the way.
And if I were to do that (move vent, hook up 2x4 or something to the under hallway joist), do I just nail those boards in, or notch out the 2x10 joists spaces for the 2x4. I want to do this right, its for a close friend.
And if I were to do that (move vent, hook up 2x4 or something to the under hallway joist), do I just nail those boards in, or notch out the 2x10 joists spaces for the 2x4. I want to do this right, its for a close friend.