Shower tray subfloor. replace chipboard with plywood or overboard?

[liam2000]

I'm looking to install a Mira Flight Low Quadrant Shower Tray 800mm x 800mm x 40mm. My bathroom currently has 20/22mm chipboard flooring. I'm looking to fit the shower tray and tile the remainder of the floor. My plan is to overboard the chipboard flooring with either 6mm No more ply/ Hardie backer to give a subfloor to tile on but when it comes to fitting the shower tray i'm unsure on the best way to go about this.

Option 1) Cut out a shower tray size section in the chipboard floor, reinforce with extra noggins and replace section with 18mm plywood flooring and then fit the shower tray onto of that plywood (that would allow the shower tray to sit 4mm below the existing chipboard and then another 6mm once i have installed the tile backer. Is there a problem with this method?

Option 2) Lay 6mm no more ply across the whole floor and fit the shower tray on top of the no more ply.


Open to any other ideas.

 

[johnny2007]

No problem with option 1 which is what i would do, in fact, that's what I have done at my place.
You know, age takes over, so less steps is always best.
Option 2 is fine, just tank the floor alongside the walls.
Of course, tank whatever option you go for, even though, many bathrooms i fitted before tanking came up, are still standing and looking good.