Redoing floor after 2 years>Advice needed!!!!

[lukeb]

Hi.
I am retiling 16m2 of porcelain tiles after whole floor has lifted up.It was originally tiled 2 years ago by contractor chipboard+12mm ply+flexible adhesive.After this winter all the tiles sound hollow underneath.Lifted one up and all of them come up by hands.Tiles can be reused as very clean but adhesive stuck to ply big time.

What will be the best solution, dont really want to scrape the old adhesive as its sound, I was going to smooth it over and than use Schluter Ditra and tile it again.It looks that all fault was caused by floor movement(as ceiling downstairs cracked and all mastic around skirting was ripped.

Is that a good idea?Please help.
Thanks.

 

[Gazzer]

When you say the floor is moving...in what way? Does it feel bouncy or is it lateral movement ?

 

[lukeb]

It looks like the whole floor moved from side to side as I can not find any deflection on the floor.It looks stable and deflection free.I think that maybe cause by joist shrinkage ???? Cant feel any movement whatsoever>

 

[Gazzer]

Then you could go over the old adhesive with Mapei Renovation screed to level it off the use Ditra or Dural Ci .

 

[lukeb]

Is that renovation screed really necessary?wanted to smoth it over with flexible adhesive up to 2mm in thicknes and with Ditra over top of that.What do you think. And thanks for advice so far.

 

[Gazzer]

No you could use flexible adhesive if you really wanted to.

 

[Gazzer]

I would though be wondering why the floor is moving as its Chipboard and then 12mm ply !!! Is the ply screwed down ? and the ply is not thick enough for tiling according to BS. Should be min 15mm.

 

[widler]

is this a new build ?sounds like the floor/joist have moved,maybe there are no noggins in the floor,if the ceiling has crack AND the skirting moved,i would defo delve a bit deeper before tiling again mate

 

[lukeb]

house is new build 12mm ply was installed in all floor tiling aplications (42 bathrooms aprox.7m2 each)and 1 kitchen was onto chipboard which has been faulty maybe because the area size 16m2????? i personaly think that is joist shrinkage to be blame.
i think i will go over existing adhesive (as its stuck like s...t to the shovel) with wet thin coat of flex and then ditra. hope it will work:smilewinkgrin:

 

[jay]

Think you need to find the problem first (movement) before moving on

 

[lukeb]

Thanks for all reply.All I can do is to guess what could be the cause of the movement.I dont think neither developer or house owner would agree to take the ceiling down to inspect what might go wrong.Ripping the ply NO OPTION as hi-quality kitchen witch granit worktops installed.So Try to get opinion what would be the best course of action.Before I start(Tomorrow) will let the developer that if they can find out what caused floor to move(at the end of the day is down to the manager or carpenter ,i dint know who else)to put it right and then get a tiler in to sort it out.

 

[lukeb]

Thanks guys!!!

 

[Alan M]

drill a hole(or few) in the ceiling with the largest hole saw you have or can get. have a look around and work out the problem. fix . screw back up the piece the hole saw cut

 

[kilty55]

luke im a bit confused...are you the house owner or tiler?

the ceiling has cracked? but you said the kitchen has high end install on it with granite so you cant rip the ply? is this a kitchen floor on ground level we are discussing? or an upper level?

 

[Gazzer]

Yeah bit confused as I thought this was a 1st floor install ? I assumed that the ceiling beneath the problem floor had cracked ?