New(ish) building bathroom floor construction

[jonny5]

I am trying to replace a portion of the floor in my bathroom as the seal round the bath has leaked and rotted the floor. It's a fairly new property (12 years) and the floor seems to be constructed as follows:

Top layer = chipboard
Below this appears to be some type of plasterboard / light concrete panel - I think this is for sound proofing.
Below that is a thin layer of insulation.
Finally there is a layer of wood panelling.

My problem is this: I can't seem to find any joists that the chipboard is sitting on. I want to cut the old chipboard back to a joist for a secure joint for the new panel. As fas as I can make out the joist are underneath the wood panelling I mentioned above.

Do I just lay a new chipboard panel on top of the plasterboard material? This doesn't sound right to me - surely the chipboard should sit on some joists?. The plasterboard material has cracked, should it be replaced? What exactly is this material?

Any help is much appreciated.

Cheers

Jon

 

[masona]

Is the bathroom on the ground floor, if so, it maybe a floating floor construction.

Can you see any nails or screws in the chipboards?

Does it look like this?

 

[jonny5]

The room is on the top floor. No, I can't see any nails or screws in the chipboards, it seems to be just resting on the plasterboard stuff.

I really can't see the detail in that picture to say if it's the same. All I an say is that the insulation (it's like glass fibre loft insulation rather than styrofoam if that makes any difference), plasterboard and chipboard don't appear to be held together in any way. They look like they are individual layers rather than a sandwich of layers glued together.

Hope that helps explain things a bit.

I forgot to mention that the joins of the plasterboard and chipboard are offset which would indicate they are individual layers.

Cheers for the help.

Jon


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[masona]

I think the only way is to cut out a section and put a thin flat bar under the ex-flooring with countersunk nut/bolt then use Gripfill to glue you new chipboard. I don't think your chipboard is fixed to the joists, only the joints is glued acting as a floating floor.