I installed an engineered wood floor, glue together tongue and groove, I leveled the sub base but missed a few spots. Primarily a spot that we replaced the 3/4 inch sub floor with 22/32inch I thought the slight difference wouldn't matter, but it does.

This creates a little bouncy area where you can feel the floating floor flex from level to touching the subfloor then back to level.

I have access to the sub floor below (laundry room unfinished).

The thought is to drill a small hole from the bottom (or multiple) and inject something, glue, sand, silly putty? something. to level out the sub floor in the areas I need.


Anyone done this or have any advice?

it possible.. I haven't heard of that practice in the professional space, but you need to be careful it doesn't cause a hump in the floor and if it works, then that's all that matters.

Might just need to live with it. This is why I don't like engineered wood floors, some thicker kinds (3/4 ") are good/better but that 1/4 inch kind, is the worst!