tiling elevated balcony

Hope someone can help, I am hoping to tile my semi cantilevered verandah,it is 3m deep x 9m wide constructed with concrete sheet 15mm thick on timber joists ( i had this engineered). I have had a couple of tilers quote but they were reluctant to take on job due to fears of tiles cracking as there is little bit of flex towards the edges. any advice on flex tiles,glues etc. also I have layed a waterproof membrane on the ac sheets, it is a rubber sheet rolled out with edges glued/sealed, can i tile straight on top of this and which product would i use
Just one more Q , can you tile directly onto fibro and what glue do you use

Can you get some trimmers along the edge from underneath to take out the flex in the sheet?

Tools

Thanks for the reply, The flex is only towards the edges/perimeter of balcony, and I must admit it is only marginal, I'm just not sure how much flex would cause cracking. There is no flex between sheets. The way it is designed it would be hard now to add further support to the metal beam, I was hoping for a method to fix problem from above, Anyone know anything about pebblecrete with a flexi resin etc ?
Ta

I used the instructions from James Hardie. I used davco ultraflex and Fuller WPM as my materproof membrane.

It now leaks and a few of the tiles have cracked. Not my proudest moment.

What you need to do:
Find out what the waterproofers suggest. You don't want to void their warranty.

Continue joints through the tiles if using direct stick onto the waterproof membrane.

The best way is to lay a reinforced mortar bed 50mm thick on a slip sheet over the tiles, this will be the strongest and least likely to crack tiles.

Cheers
Pulse

Mate try and take as much of the flex out of it as possible can you get bracing underneath it? I recently renovated my bathroom where i also extended it I had to put a section of CFC sheeting down as there was an old laundry chute hole i to cover up and it met with floorboards my bother in law laid the cement bed compacted screeded it off then let it go slightly off before getting a straight edge and goudged a groove the full width of the room where the cfc sheet met with the floorboards this inturn made the slab of sand cement effectively 2 slabs each independant of eachother making sure to tile either side of the joint after the tiles were laid he filled the groove with a flex grout he mixed

Never heard of flexible pebble crete but if you go to your local MCdonalds on the kids playgrounds they use a flexible flooring surface that is actually made out of used car tyres and is soft

I am sure there is heaps of other flexible surface finishes on the market the other that springs to mind is Rhino floor coverings that advertise on the idiot box

I hope I have been some sort of help

thanks tools,pulse, patty for reply's, I will keep thinking and hope something pops up, I didn't really want to lay a sand/cement screed due to the weight, I think I worked out it would be about a ton !

I thought you said you got it engineered?

Did you forget to take tiling into consideration even so if it has been engineered properly the engineer would have more than compensated covering the additional load of floor coverings... especially tiles I am sure you can tile straight over CFC sheeting by glueing the tiles down and grouting over but if you have any flex in the verandah at all you will almost certainly run into strife later on down the track do it once do it right did the tilers even suggest anything to try and take the flex out of the deck? I dont know how thick this rubber membrane you have put down it might take a little bit of the shock factor out but most outside decks i have seen they only waterproof the joins and the wall returns

I'm guessing here, but if the 15mm CFC is flexing could you lay/glue another sheet of CFC on top to stiffen it up?

I just spoke to my builder who is going to take a peek at prob, hopefully some answers soon

we are going to brace the verandah back to the house with a cable system with adjusters to tension and take the wieght