Question regarding floor construction

[skvsn]

Hello,

I'm replacing my flooring on the ground floor. After lifting up old laminate I discovered that underfloor is made of T&G chipboard which are not fixed to the base by any means. They just float and probably glued together at T&Gs.

The problem is that they are quite uneven (max difference is about 15mm).

The questions for me at the moment are:
1) what type of floor construction is it? (the house was build in 1980s)
2) why it is not recommended to put primer and SLC directly on chipboard without additional layer of plywood? I looked at F-ball 131 primer technical data on the website and it says that it can be used on absorbent surfaces such as plywood and chipboard.

Kind regards,
Sergey

 

[tony1851]

If it's a new(ish) house, it's possible the chipboard is a floating floor laid on top of a thin layer of insulation.
Unfortunately this is about the worst sort of floor - they're known for squeaking and becoming uneven.
(Don't know about the primer).

 

[skvsn]

So am I right to suppose that it is concrete subfloor + some insulation + chipboards laying just on top of insulation? Or there might be some kind of joists/battens suporting the floorboards?

 

[tony1851]

So am I right to suppose that it is concrete subfloor + some insulation + chipboards laying just on top of insulation?

That's usually the case.

 

[skvsn]

what would be the best solution in this case? I plan to put solid or engineered oak on top of it...