Levelling chipboard

[Neber]

Anyone know what I should use to level a 10mm dip in chipboard, it's about 500mmx2000mm in area gradually increasing to 10mm from edges (the length of the dip is at a right angle to the future wood flooring). I am about to glue down the solid wood floor onto it. Adhesive instructions say it can go onto a levelling compound resistant against plasticizer migration (whatever that means).

 

[Neber]

Please help

Now realised there are a couple of areas of chipboard that have drooped about 10mm along the length of a joist, to fix it properly I'm starting to think I should lift the floor and fix the joist but as it is T & G chipboard (and would be scrapped if lifted) I would then have to replace it all and might as well do it properly with Ply which would cost £350.
Is there a simpler way to level a wooden subfloor that would still alow gluing the solid wood? Or should I pay the money and replace with ply and secret nail?

Any help much appreciated

 

[big-all]

is the dip between or accross the joists!!!!!!

if your shure the floor is ok and your top flooring is at least 18mm thick i would just pack out abouve the joists to bring the floor to the correct height assuming the joists are around 16"

if its 9mm flooring go for 9mm ply taperd at the edges and make shure its unsuported for no more than 3"

 

[Neber]

Thanks big-all

It is along the length of the joist (not between) as if a couple of the the joists sag in the middle. the joists are 16" or less.

So do I just cut the T and G chipboard along the centre of the joist with a circular saw pack it with ply (glued down) add a couple of noggins at the board joints, then screw down the boards?

Sorry don't understand:
"if its 9mm flooring go for 9mm ply taperd at the edges and make shure its unsuported for no more than 3"

The floor is 18mm Chipboard the flooring is 18mm solid Oak, do you mean I should lay 9mm ply across the whole floor, if so should it be nailed down and flooring glued on top? Why do I need the ply if the joist is levelled?

Many thanks

 

[big-all]

your options are

gain accsess to the joists[by removing a section big enough to get under the floor]then
pack out/lift the joists to level the floor then reinstate the floor

or build up the present floor till level for the new floor to sit on[my suggestion above]this is the option i was suggesting above if your new flooring is structural [18mm plus]

Sorry don't understand:
"if its 9mm flooring go for 9mm ply taperd at the edges and make shure its unsuported for no more than 3"

if the new flooring your laying on top is 9mm laminate it needs more support thus the suggestion of sheet material

you could of course just lay strips 3" apart to support