Hi experts,
I recently purchased at auction what I thought was a good deal on handscraped floating engineered flooring. It's 5 3/4 by 1/2 thick, 3 ply red oak. The problem I discovered after bring this home is the arching of the planks. The lengths are 31 1/2 and 63 inches long. While true along the length, the boards arch by 1/4 inch typically for the shorter lengths and 1/2 for the long lengths. My plan was to float over existing sheet vinyl, which is glued down over 3/4 particle board, which was installed over 3/4 plywood subflooring. The existing vinyl and particle board eliminates the option of glue or nail down for the engineered hardwood. Can this flooring be installed without removing the vinyl and particle board or is the arching too extreme? I can't afford to throw this stuff away and start over! Any advice is appreciated...

Many brands of floating type floors are bowed or arched when they come out of the cartons. It has always made me nervous but the typical response from the manufacturer's has been that it's ok and the floor will settle down after installation. Perhaps attempt to engage the T&G on some boards and tape them together and see how they lay. I'm sure you can't return the stuff so what do you got to lose by trying.

As you start to assemble the floor, things will start to lay flat as stagger from one board and row to the next, as strength to the assembly.