How to level the plywood surface for parquet flooring

[Scoder]

We encountered an issue while changing the parquet flooring. The level is uneven at the base.
Is thin layer of concrete/cement the best way to fix it?

The underneath is plywood and there is a room below it.
In the picture attached -
1. This was the vinyl sheet plus very thin form sheet
2. After taking out these sheets, its plywood and that is uneven. how it is uneven i dont know.

I guess we need to level the whole room before we can install parquet flooring, question what is the best way to level it?

 

[ricebridge]

Well, first of all, you need to find out what the cause of the unevenness is and whether you need to do anything about it. Before doing that, it’s pretty futile to do anything else.

Cement or concrete won’t work, it’ll be too thin. What you need is self-levelling compound/liquid putty (flytspackel). But that’s for after you’ve torn up the floor and examined it thoroughly.

 

[Scoder]

Uneven is few millimeters. For that also we need torn apart underneath floor?
Because it is few millimeters that somebody suggested to use cement.
But i am not sure if it is wise to use cement on top of wood

 

[ricebridge]

Thing is, have the beams underneath rotted, for example?

Happened to me.

 

[arneri68]

The floor joists can be uneven. Looking at your picture there is an interruption between sector 1 and 2. What is between the chipboard in sector 1 and 2?

 

[Scoder]

@arneri68 - there was a wall there. it was taken down so floor has to be redone.
But the level is uneven at another place as well. like in sector 2 itself

 

[Scoder]

The contractor used Byggspackel on top of primer to level up the floor.
Is it safe to use on wood?
is this a common way to level up floors?