New frame noise when walking on floor

[315RLTSinPA]

Please correct me if I am wrong. Aren’t all Grand Design model floor constructed out of plywood? Irrespective of bumper or 5th wheel type.
I know all GD roof sheathing is OSB.

Thanks

No. All the travel trailers and 150 series 5th wheels use the laminated foam and lauan floors. They are about 3 inches thick.