Planning new vinyl Plank floor: How perfect does the old floor need to be?

[SidecarBob]

We are most of the way through an extensive kitchen renovation and the last major part is going to be installing a click lock vinyl plank floor. I have determined that the sub floor is close enough to flat but I need to determine whether I can lay the planks over the original 29 year old sheet vinyl. It is substantially intact and not worn through anywhere but has lifted at the seam where the wall bumps out for the bay window and there is a 3/4" hole where the wire for the dishwasher used to come through the floor.
Can I just re-glue the part that has lifted? If there is a small gap do I need to fill it with something?
Do i need to plug the hole? If so, what would be the best way? (I have access to that part of the floor from below)

 

[havasu]

Sounds feasible. You could use rubber cement t seal the edge and find a scrap of same thickness flooring for the hole and lay it. Pay attention to the required staggering.

 

[breckrider]

I need some advice on this too. I'm putting in vinyl plank flooring and have discovered that in my mudroom, there's a point about 3' in that has a drop to the back door of about 2". The red line in the first picture shows where the floor begins to drop. The second picture shows the drop.

My first thought was to lay the tiles as far as the drop then put a threshold. My second thought was to lay it with an edge at the drop, then start new on the other side of the drop, go to the back wall, and maybe put grout or something on the seam.

I hope this makes sense.

 

[SidecarBob]

I'm no expert but I think my first priority would be finding out why the floor drops off like that. There's no point in putting a new floor on top of structural problems.

Sounds feasible. You could use rubber cement t seal the edge and find a scrap of same thickness flooring for the hole and lay it. Pay attention to the required staggering.

As I said, the hole in my floor is where the wire came through the floor to power the dishwasher so I don't think putting some vinyl flooring over it would make any difference. The hole was actually only about 5/8" so I bored ot out with a 3/4" bit to get clean wood and glued a short piece of 3/4" dowel in.

 

[Rusty]

You can always fill small gaps and holes with a cement based floor filler.

 

[breckrider]

"I'm no expert but I think my first priority would be finding out why the floor drops off like that. There's no point in putting a new floor on top of structural problems."

This area was originally a back porch that was later enclosed I believe by the original owner. I have had the corner by the exterior door reinforced but not jacked up. If I'm going to jack it to level then I'll just tear it all off and rebuild it but that's way down the line. I'm going to try my idea and see what happens.