Shower tray installation problem

[tireetim]

About 3 months ago I installed a shower tray (Pearlstone resin) onto a concrete floor. It was laid on a 5:1 mortar mix (About 10-15mm) and levelled. It was then left without the surround fitted for 3 months as the walls were not ready for tiling. It is in a corner and has been sealed with silicone against the wall as per the instructions. Today I have gone back to it and found the it has lifted by about 5mm on the edge that is away from the wall (it's an offset quadrant 1200x900). It's as though the tray has warped. It flexes back if you put weight on it but obviously is not stuck to the mortar although it feels well supported if you do stand on it and bend it back. The edges against the wall seem fine but I guess the silicon is holding those in place. Can anyone please advise what I should do.
My thoughts are :
1. Leave it and tile / install the shower surround and hope the weight of the surround holds it down properly.
2. Try to stick down the lifting side with a grip fill type of product and weigh it down until dry.
3. Lift it right out and dig out the mortar bed and try again from scratch risking the same thing happening.

Thanks if you can help me.
Tim.

 

[tireetim]

Anybody? Somebody must have experienced this before.

 

[muggles]

Take it out and start again, trying to bodge it will never be satisfactory

 

[longdogs]

The weight of the surround will not be enough to hold it down and I doubt if grip fill will work either. Unfortunately you need to remove it and start again. the 5mm out of square you could probably get away with but not the movement.

 

[tireetim]

Thanks muggles and squeaky.

I couldn't face pulling it all out and starting again so I have lifted it as much as it would go and put a whole tube of grip fill underneath. It's now sat with 5 full rhino buckets of water holding it down over night and I'll see how it looks in the morning. Got this sneaky feeling you are both going to be right and it will need to be re-done but had to give it a try.

 

[longdogs]

Worth a try I suppose. Lets hope it works for you.