Tiling bathroom floor first, install shower tray, then tile walls

[curium]

I know the normal method of work is top down so people would normally tile the walls (up) and then do the floor.

I'm considering tiling the floor first purely because I wanted the tiles (porcelain) to continue under the shower tray so any leaks (fingers crossed) are contained within the bathroom rather than soaking into the ply and the joists.

I know the shower tray (2 up stands) has to be in before the wall tiles so I would need to tile and grout the floor first if i insist on the tiles continuing under the shower tray.

Is the only down side to this method of work that I would have to get some protection in for the floor once it is done before I tackle the rest of the bathroom?

Thanks

 

[PrenticeBoyofDerry]

You batten the wall above the last wall tile cut, then tile wall upwards from there, leaving the last row of tiles at floor level off (below batten).
Then you can do the floor tiling, insert tray and complete last row of wall tiles.