I am preparing my subfloor for cork plank flooring. After removing carpet and pad I have discovered that the center 10' of the floor for the length of the room is very level and even. But from there to both L and R walls the subfloor drop dramatically. This house is only 2 years old and everywhere else in the house seems to be pretty good. Floor joists are in good shape. Just seems to be shoddy track house construction. I was planning on using a self leveler to smooth and even up the floor. The one farthest out corner drops 1 1/4" from the center of the room.

What do I do?? Should I level it up 1/2 the difference and float it back. What are the downfalls to not haven a perfectly level/even floor??

Thank you for all your answers.

All I can say is uneven wood substrates are harder to fix than concrete.

pull the plywood up from the crowned /high area and plane/cut the joists down..sister a joist to the existing if 2x 8 or less.

reinstall new plywood.

if still out you can than use some SLC.

What if it's an engineered floor joist (I Beam) system? And shouldn't your house still be under warranty for issues like this? I'd call the builder and maybe the licensing board if need be.
Also are you checking "level" or for flatness. Flatness standard for floors is usually 3/16 in 10'.