Replacing chipboard floor for tiling advise

[Waluigi]

I’ve experienced it many times, Boggs.

In fact, I have taken up many a bedroom carpet to install timber between the joists so that I can take the whole floor up. Amazing how many builders ignore using a double joist under a stud wall in preference of no joist at all.

I still don’t see using ply/chipboard and then over-boarding as wrong necessarily but I do take 3falls point and shall be looking into this method further.

 

[Dumbo]

Using 6mm Hardie over new chipboard is what I would usually do, never had a problem but we all do things differently.

When I do a job I take into consideration how and what damage it might cause when it has to be removed.
22mm t&g No More Ply screwed directly to the joists is a great idea in theory but what damage might it do to joists when it has to be ripped up?
Floors are easy to replace, joists not so.

Joists under walls is a point I make from experience, if everyone cuts back the floors to the nearest 15mm without a joist under to support it the wall may well start to drop with the weight of tiles etc on it. It’s better to cut to the nearest joist inside the bathroom.

I worry more about floor sagging with no support next to walls . Also I don't make jobs to come apart .