Advice re failing bathroom floor

[CalvinHobbes]

In a relatives house, currently dealing with cancer, will get home next week. Turns out her wet room floor has failed. Insurance won't cover. Problem is it's the downstairs bathroom and she is using a walking aid. So I am here now and digging in to see which way joists go. Do they need replaced? 

[Andehh]

Rip up more of the floor, sister all the joists thoroughly, few noggin for good measure. Hardie floor down, with decent amount of gorilla glue then tank properly, and tile?

[marshian]

They don't look sodden but then you've not got to the one near the drain?

 

I was trying to work out if the floor is ply or OSB but either way I would not expect tile grout on wooden floor to be acceptable as a wet room...

[CalvinHobbes]

[CalvinHobbes]

Sorry floor very soft around drain, shocked to see NO plywood under that area. I just need to make sure if she uses loo that there is plywood under tiles in that section. Medic coming out with her for a test run re mobility on Friday, I didn't want either falling through floor. Doesn't appear to be plywood under tiles in front of sink. Holy moly. 

Edited February 5 by CalvinHobbes

[Nickfromwales]

Jesus. That’s shocking.

 

I used to love destroying insurance companies, all you had to do there was say you fell over and the impact broke the floor. Automatically gets the claim through under ‘accidental damage’.   
 

May as well just get stuck into it and rip the lot up, it’s near total loss. 
 

To minimise grief / time, cut around the tiles nearest to the sink and WC and perimeter, on the nearest grout lines, slide more 4x2’s up under the sink and WC to reinforce those point loads with screws and D4 glue, repair all flooring into shower area, and P5 board the lot flush to the edges of the tiles / perimeter you’ve preserved at outer walls and WC / sink. 
Get a mineral floor laid over latex (to get the falls) and that’s a quick way out of this. 

[Nickfromwales]

Oh and yes, defo sister new timbers both sides of every joist, extending as far under the preserved sections and perimeter as you practically can. 
 

Weight will not be a problem at the perimeter and sink, just focus on the shower area and WC. 

[CalvinHobbes]

Much appreciated, builder coming next week and may do a cause of damage report, no point paying for a loss adjuster if the contract means they won't pay. 

Edited February 6 by CalvinHobbes