How straight should a tile ledger board be and what would you recommend me to use for that ? 2x4s are pretty crooked and it is really difficult to find one that is really straight if it matters, I am working with 24"x24" tiles
This is what I ended up doing Finding a straight and cheap piece of lumber at Home Depot (or any other similar store) is going to be a challenge. So I picked the straightest piece of 1x8x8 pine shelf and I asked them to cut it in half along the long side ...that cut will always be straight on both sides ...their saws are not precision saws but they do cut straight
I do not trouble myself with a temporary ledger board being straight. As long as it is reasonably straight, tile shims will bring the tile to a straight line. In many cases tile needs to be shimmed here and there in order to keep the rows looking good. These shims should be on hand along with a straight edge as a rule when setting tile.