Ply lining over tile mortar?

[iaingray741]

Hi all,

I'm currently renovating my bathroom and have just removed some heavy duty floor tiles. They've left a load of nasty grey mortar that i'm struggling to take off without removing chunks of floorboard with it!!!! The floorboards aren't in great shape below and are flaking up when i get the chisel on the the mortar.

Im trying to keep the cost down, so I was considering just lining the floor with plywood over the tile mortar. Is that an acceptable practice?

Would 5.5mm exterior ply be suitable for this? The tiles i removed were about 8mm thick, and i'm just planning on a vinyl floor so height shouldn't be an issue.

I was planning on screwing it to the existing boards and leaving 1 access hatch for services.

Any other advice?


Cheers
Iain

 

[vinn]

OP,
Why not post pics of the floor and the room?
The tiles were stuck to T&G floorboards?
There are a number of threads on these issues in the tile forum - I'll ask the mods to transfer you.

 

[iaingray741]

No problem...i'll get some photos.

Yes, the tiles were pretty hard to get off. Got them off...and now i'm left with the mortar!

 

[iaingray741]

Floor without the tiles

 

[iaingray741]

Chunks coming up from the t&g boards

 

[vinn]

You have a choice:
1. Hire a floor tile grinder - it will clear that floor in no time. Then use 12mm ply.
2. Knock down the highest spots and prime and spread a very thin coat - merely a filler - of SLC to give a flat floor over the whole room. Then use 12mm ply.
3. Using ply straight over what you have might risk crunching sounds in traffic areas, & possibly eventual loosening of the ply.

Consider the rad supplies, the wastes from fixtures and all pipework below the floor before fixing ply.

 

[iaingray741]

Cheers mate...I'm going to hire the tile grinder (£18 for the day), so I'll see how that goes.

Would you out ply over the whole floor? Even under the bath?

Cheers

 

[vinn]

Best practice is for the bathroom to be an empty shell for first fixing etc.
But if the bath tub is fixed and staying then as a DIY'er just run the ply or whatever up to the bath. - not under it.
But run ply and finish floor under the WC & ped basin or vanity.

Depending on the size of the room, its best to do an "easy-fit" template and, using the template, cut the ply in one piece and drop it in place

Remember that the screws must not penetrate below the sub-floor T&G boards.