Flooring advice

Quorden

After some advice regarding regarding prepping a floor ahead of laying new vinyl or laminate planks in my lads new house (new to him at least).

I've removed the vinyl flooring that was in place, in the kitchen this was laid on 12mm ply, (still in situ though looks a little murky) which in turn looks like it was fixed directly onto old tiles, suspect I'll need to use the multi-tool to remove the old fixing bolts as they're as solid as can be. In the adjoining bathroom this flooring was laid directly onto tiles.

After much googling, my thinking is that once everything is cleaned up, repaired where necessary, and all the old ply is removed that I lay a vapour barrier then lay new ply throughout, possibly WBP ply, and attach it with concrete screws to through the old tiles into the concrete below.

Any advice gratefully received.

Kitchen

Bathroom

NoMore

I think you want the DIY section!

sheenas

The plywood is there to make the floor level, so I would not remove it unless there is a good reason. Removing the tile floor will make quite a mess and you would also have to use something like a self levelling compound to make the floor level again. This would also provide a water proofing barrier. 

ButterCheese

No real need to replace the plywood unless it's rotting or rotten.  In the kitchen, you could also lay directly on to the tiles if they are flat and in good condition, but you'll need to fill the gaps between the tiles otherwsie they'll show through the Lino.  I did that with silicone in my kitchen and it is fine.

For the bathroom, I would also consider the waterproof tile backing.  It's more expensive but very easy to work with and cut, and provides a nice cusioned surface to walk on in bare feet.  It's not marketed as flooring, but I used it in our shower room and it's great.

Albermarle

A bit late now, but you might have been better just laying the new floor over the old vinyl floor.

Quorden

Thanks all, the current plywood is rotten in places and the portion I removed did have mould on the underside so does need replacing, think it's been down for decades. Think will stick with the idea of vaper barrier and new WBP ply. Do like the idea of waterproof tile backing, have looked at it, but the lad has a tight budget.
Onwards and upwards. 

danrv

If the tiles in the bathroom are solid, you could prime with SBR and use self levelling compound as mentioned. 
Doing the same in my hallway with Mapei Ultraplan 3240.