advice required please

[thegwads]

pulling up a tiled floor in en suite that has been laid with what looks like tubbed flexi tile on wooden floor adhesive. there has been a leak, and on pulling up the tiles it is ripping chunks out of the chip board. 1st floor flat in big london posh appartment, so under chipboard is polystyrene insulation then concrete floor. chipboard is 25mm i would say, and 18mm of poly insulation.
i need to put a new floor in, what is your advice.
i thought, rip out all bad stuff,, i.e all the chipboard, then grip fill some 3 x 2 cls stud timber to the concrete base, at 150mm or 300mm intervals, and lay 15mm ply or 18mm or whatever it takes to get back to the original level.
does this sound a plan, or does someone else have a quicker idea which will save time?
cheers

[doug boardley]

I'd say the insulation is more acoustic than thermal,ie stilettoes will make a helluva lot of noise to apt below, so I would leave insulation down,make up with 18 mm ply(exterior grade) or thicker to get to required height, if possible put in an uncoupling membrane. Oh and make sure leaks been fixed

[thegwads]

top work, no one lives below, garages i think. will batten out the floor and have 18mm ply ready to go on which will be screwed every damn inch!!!

[silver]

Is it a leak thats caused it or is it continual water soaking through from stepping out from a bath or shower ? or someone not bothering to use the shower door or curtain.......with a bit of imagination...."I have got a wet room" ! LOL
Either way if it was me, like Doug and you have said I would get all the chipboard out, leave the sound proofing and reboard to the right level with ext ply screwfixed to baton at every 150mm.
If its a small floor, I would tank the floor too, its not a big cost and will safeguard any water ingress.....if its a big floor (posh London flat) ? it will do no harm to tank a good area around the shower or bath exit points.
....its what I would do in my own house....extra time I know and I know you want to save time but.... I think its worth it.

How is the current chipboard fixed in you havent mentioned it ?...is it floating on the poly ? you dont mention there are any previous batons... if there has been bounce in the floor .....?

[thegwads]

floating on the poly, and linked throughout all the rooms. no pipes under, just concrete. water has got in from above. no battens down, so will grip fill and screw and plug to concrete all over the floor so we will have no flex. will leave poly in. have got the old rip saw out to cut out the floor in sections, once the tiles are up, which is proving very very hard!!!!
cheers for help and advice

[Dave]

That wil be your best way really.....you need to remove all deflection in that floating floor......