Hi guys,

I'm working on my first DIY project for installing engineered hardwood flooring on my house. I ran across the following issue: As per the below images, there's an elevation which prevents the board from being laid out flat. The elevation is such that the board will drop towards either way, depending on its position.
This elevation is at the junction of two plywood boards, perpendicular to the boards I'm installing and I'm assuming there's a joist right underneath this junction.

Has anyone tackled this before? I've tried hammering some ring shank nails along the junction but no good... I'm thinking about removing the nails and using a planer to shave off some of the plywood. I'm only concerned with the thickness of the plywood.

Below are a couple pictures I took... Any comments or suggestions are much appreciated!

Thanks, Rick

https://ibb.co/hWAuJc
https://ibb.co/mE9X4H

Go to Home Depot or similar tool place and rent an subfloor edger. You need to sand that bad boy down, don't worry about plywood thickness, the flatness is far more important. They should provide or sell you the right discs for the job.

You probably have more than one seam that's high, so you might as well check everywhere with a 6ft or greater straightedge and then hit them all while you've got the rental. Save yourself a lot of headache after the fact.