help with leveling a dip in bathroom floor

[jnjw]

hello,
I have a 5x5 ft bathroom covered in sheet linoleum and i am trying to lay floating rigid core vinyl plank over it.
I have a 2 foot wide by 3 foot long dip in the floor that tapers down to 1/4 inch deep in the center and the sub floor is like particle board material.
it starts at the toilet flange and extends 8 inches to to the edge of the wall and 2 ft from the flange in the opposite direction.
any ideas on how to level this before laying the plank flooring down?
thanks for any help with this!

 

[Incognito]

I would just patch right over the vinyl with Ardex Feather Finish. Generally I can trowel it flat. If needed I'll use a screed to pull across the high spots and fill the lows. Let that set like you would fresh concrete and trowel it smooth as it sets hard. You can always 2nd coat like you would patch drywall seams.

 

[jnjw]

o.k, sounds like a plan.
thanks for the help i appreciate it!