About 9 months ago we installed stand-woven bamboo floors throughout our whole house. The floor is a click-lock system (which I would not recommend, but that's another post).

The problem we are currently trying to address is that in certain places the planks...give. I'm not quite sure how to explain it, but there is a certain bounce to the plank, or rather a hollow under the plank that allows the floor to move up and down. I am not talking about side-to-side, expansion movement. This is purely vertical. In some of the more extreme cases, you can even see the plank moving up and down, mostly from the way the light reflects off of the wood.

The problem is not due to expansion or contraction; it is purely due to what seems like an uneven subfloor and the floating, click-lock system combining for a poor floor in general.

The "company" (I use the term loosely) we paid to install the floor also leveled our concrete slab subfloor. We've since called them to address this vertical movement of some of the planks, and their solution is to drill into the wood (in an inconspicuous area, like in the cracks between planks) and inject glue under the plank to fill the hollows. They did one test spot, though I don't think they used enough glue. It's not quite as bad as it was, but it still gives some and squeaks.

My questions:

1. Does injecting glue under a floating floor have any reasonable expectations of success for such a problem? It seems a silly solution to us...

2. What would be a reasonable solution? We were thinking of pulling up the offending and surrounding planks, cutting out the underlayment, having them level out the hollows, and then replacing the underlayment and wood. This might be excessive... or is it?