put dura mat down on new green style chipboard flooring with flexible adhesive then tiled cermic tiles using flexible grout is crackingflexible adhesive after 2 days

We would need more info. What adhesive, Is the floor solid , What grout did you use ?

hello,do you mean durabase ci matting?

personally i would have overboarded the chipboard with cement boards if the sub floor was solid then tiled direct

did you check the sub floor?
what exactly is cracking also,ta

hi the floor seemed solid i put yellow dura mat down with bal flexible adhesive then tiles with same then grey bal fleible floor grout some grout now is crumbling and coming loose hope i explained properly

Are the tiles loose ?

strangely enough no

So it would be best to assume the grout was the problem ? out of date? mixed incorrectly ?

did you have noggins (dwangs) aplenty between the joists?

In what areas and how much grout is cracking ?

Is it a floating floor ?

The reason why we overlay with cement sheet

it really does sound like a deflection (vertical bounce) issue imo, as Dave asked, is it a floating (ie not securely fixed to sub-floor) floor?

I really do not know why anyone would want to put a crack isolation membrane on a floor like this.Serves no purpose, would be better beefing floor up with cement board,cemented and screwed down. Crack isolation membranes will not compensate for deflection.